Oral History Transcript — Dr. Kaj Strand
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Kaj Strand; December 8, 1983
ABSTRACT: Recounts Strandís (b. February 27, 1907) career in astronomy which began with graduate work at the University of Copenhagen (PhD, 1938, astronomy) and included positions at the Geodetic Institute in Copenhagen (1931-3); at the University of Leiden (1933-8) ; at Swarthmore College (1938-46) ; at the University of Chicago (1946-67); at Northwestern as Director of the Dearborn Observatory (1947-58) ; and at the US Naval Observatory as Director of Astrometry and Astrophysics (1958-63) and as Science Director (1963-77). The interview concentrates on Strandís astronomical research at the Naval Observatory on photographic observation of double stars, stellar parallaxes, and orbital motions in double and multiple systems, as well as his administrative activities there. He also recounts his early family life and education in Denmark, and his experiences in the American Army in WWII.
Session I | Session II
DeVorkin:Dr. Strand, could you start out by spelling your entire name for us?
Strand:Kaj Aage (pronounced Auga) Strand.
DeVorkin:Dr. Strand, I know that you were born in the outskirts of Copenhagen in 1907. Could you tell us something about the background of your parents, your fatherís and motherís names, siblings, something about your home life!
Strand:Well, my father was a goldsmith, and had a jewelry store, and my mother was born in Sweden but her parents moved to Copenhagen when she was a very small child. I had two sisters, one seven years older than I and one four year younger than I. We lived in a suburb close to the shore of Orefund — the sound between Sweden and Denmark, and I was reminded of Tycho Brahe — the view that we had of the island Hveen, when walking down to the beach from our home.
DeVorkin:You could see the island?
Strand:The island was in clear view from the shore, a short walk from our house. I went to a public school, in the same sense that we have public schools here; there were, and are very few private schools in Denmark. Fortunately, I went to the school at a time when changes were made in the system. After the fifth grade, the students were divided between those who wanted to go towards higher education and those who would end school after seven years, and then perhaps go into a trade. The four years after the fifth grade were called the middle school. We had four years of special classes in mathematics and in languages, English foremost, then German, and in the last year Latin. After completion of the four years successfully, you had a choice between going to gymnasium for three years, or completing school after an additional year.
DeVorkin:Let me ask you something about your home life. Your father was in a trade?
Strand:He was a goldsmith, and had his own store. He died when I was quite young.
DeVorkin:You said this was a new educational system?
DeVorkin:Was there any question that you might not go on, might follow your fatherís trade?
Strand:No, there was no question about that. I had been very studious ever since I began school, and there were ideas that I certainly would further my education, and become a teacher or something of that kind.
DeVorkin:Your fatherís name?
Strand:Viggo, middle name Peter.
DeVorkin:Your motherís name and maiden name?
Strand:My motherís maiden name was Constance Malmgreen.
DeVorkin:What was her educational level, and your fatherís educational level?
Strand:Well, they were both educated through the seventh grade.
DeVorkin:Thatís through the middle school?
Strand:Middle school did not exist when they went to school. Seven years of school was normal at their time. My mother had had ideas about wanting to go on to become a teacher, but her father didnít approve of that, didnít think that that was a proper thing.
DeVorkin:Was reading a common activity in your family when you were a child?
Strand:Oh yes, we read quite a bit.
DeVorkin:Did you read as a family, or individually?
DeVorkin:What books do you recall reading as a child and what source did you use to get them?
Strand:We got them in the school. We had a very good library in the school. There were books for all grades, so you picked whatever you liked.
DeVorkin:What did you pick?
Strand:Oh, I picked quite a few of the books of that time written for boys on, shall we say, history and adventures of various kinds. I did read some American books in translation. I had also other activities. I was for instance a Boy Scout. I went through to become an Eagle Scout. I did quite a bit of camping and so on.
DeVorkin:Do you recall any popular science books, natural science books, astronomy books that you read early on?
Strand:Well, we had very good textbooks on the subjects we studied in school. In fact, we spent much time on homework throughout school.
DeVorkin:Were these textbooks, class books, provided by the schools, and were they the types of textbooks that are generated through an educational system, such as we have today in the United States?
Strand:They were generated through a national educational system. I think they were very good.
DeVorkin:Were there any recognizable scientists involved in writing these textbooks that you might recall?
Strand:Not that I recall. Later on in gymnasium there were some popular books by Elis Stromgren that we read.
DeVorkin:Do you recall in the gymnasium any particular science courses that you took that had memorable teachers or influenced you in any way?
Strand:Yes. I can mention for instance, our teacher in mathematics became quite close to me, and in fact, later on, after I had graduated from the university, I taught his classes at the last year level of gymnasium.
DeVorkin:What was his name?
Strand:Sigurd Keistensen. The reason for it was that he suddenly was appointed to a position as chairman of a special council in the government, and so I did this as a substitute for him.
DeVorkin:This was your first teaching experience?
Strand:That was my first teaching experience, yes. Now, another teacher I had in the gymnasium was a lecturer in physics, Johannes Braae, who had been at one time observator at the University Observatory. In other words, he had been second in command or somewhat similar to that.
DeVorkin:This is in Copenhagen?
Strand:In Copenhagen. And he left for personal reasons. His position was later taken over by Miss Vinter Hansen. I donít know whether youíve heard of her?
DeVorkin:Julia Vinter Hansen?
Strand:Julia Vinter Hansen, yes. She became the successor to Johannes Braae. He had worked on the origin of comets, and had written a thesis that he expected would be accepted for a Ph.D. degree, but Elis Stromgren refused to let him get the degree. Later, at least part of his thesis was included in a publication by Elis Stromgren himself, with the remark, ďMit wesentlicher unterstutzung von Johannes Braae.Ē
DeVorkin:What does that mean?
Strand:Acknowledged ďwith substantial support from Johannes Braae.Ē
DeVorkin:Was this a typical thing for Stromgren to do or was this an unusual thing to happen?
Strand:Well, I really donít want to comment on that, but the upshot of it was that Braae resigned from the observatory and became a lecturer in the gymnasium system and he was my professor or lecturer in physics and astronomy.
DeVorkin:How was he as a lecturer? Was he talking classical astronomy? Since this was in the twenties, was he saying anything about modern physics and astronomy?
Strand:No. Very little. In fact, itís hard to say what there was in the way of modern astronomy at that particular time in the schools. Of course, there was some, but not a great deal.
DeVorkin:You werenít yourself aware of modern astronomy at that time in the gymnasium?
Strand:Only very little.
Dick:By modern astronomy you mean astrophysics as opposed to classical positional astronomy?
Strand:Thatís right. It was only classical astronomy at that time.
DeVorkin:You entered the University of Copenhagen?
Strand:Yes, I did, in 1926.
DeVorkin:Iím curious, you seem to be the first one of your family to enter the university. Is this true? Did you have any uncles or did your older sister?
Strand:No, they didnít. I was the only one in the family.
DeVorkin:Is this unusual?
Strand:No, that was quite common. I would say that many of my fellow students came from families, where none in the family had university education.
DeVorkin:Was there a particular reason? Did you have a choice, in choosing the University of Copenhagen over any other?
Strand:There was only one university at that time. My mind was more or less set upon becoming a teacher in the gymnasium system.
DeVorkin:Was this a teacher of a specific subject, math, physics?
Strand:Well, when you entered university you could go various lines, but the one in the natural sciences and mathematics was combined, in the sense that you have to study astronomy, mathematics, physics and chemistry. These were the four main subjects. And you had a very intense study of these subjects for the first part toward your final degree.
DeVorkin:What was the first degree called?
Strand:No, it did not have a name, because it did not mean that you had qualified yourself for anything special, but it was the general study of these four subjects. At that time, there was quite a large number of students going to the university. I think part of it was because the economic situation of Denmark wasnít very good at that time. Jobs for young people were scarce. And so we had quite a large number of students going into this particular field. But the examination at the end was very strict.
DeVorkin:Was this after three years?
Strand:No, normally after two years. I took it after three years, because of the strictness of the examination and I wanted a high score. I also had extracurricular activities and interests.
DeVorkin:Oh, like what?
Strand:I was in the academic Rifle Corps, which corresponds somewhat to the ROTC here. I was quite active. So I took the exam after three years. We were 23 who took the exam, and only seven passed.
DeVorkin:Once you took the exam — if one didnít pass it, did you get another chance at it?
Strand:You could try again a second time. But few did that.
DeVorkin:I take it you passed?
Strand:Yes, I passed.
DeVorkin:Do you know what your ranking was?
Strand:No. This was all rather personal and not published. But I had a sufficiently high grade that I could later go on to a more advanced degree.
DeVorkin:Which was your intention.
Strand:No, not at that time.
DeVorkin:This first degree would have allowed you to teach?
Strand:No, it wouldnít. It was only the first part of it. Then you went into your specialty. But first you had to take a year in which you more or less prepared yourself for subjects that might come up in your teaching in the gymnasium, and it was, at that time on a personal basis with the professors, because we were a small group. Previously, you rarely knew your professor. For instance, I had Harald Bohr, the brother of Niels Bohr, as my professor of mathematics, whom I only saw at the examination.
DeVorkin:For your astronomy, who did you have?
Strand:I had Elis Stromgren.
DeVorkin:What are you recollections of Elis Stromgren?
Strand:Well, in some ways he was somewhat of a difficult man to deal with.
DeVorkin:Was he the one who convinced you to change to astronomy? Because somewhere in this time you did change.
Strand:Yes, I changed.
DeVorkin:Iíd like to know if you can recall when and why.
Strand:When and why I changed from mathematics to astronomy? Well, it happened during my first three years.
DeVorkin:So it could have been after you took your first exam?
Strand:Yes, by the time I passed my first exam, I had already made up my mind that I had two choices. I wanted to study mathematics. But I looked at mathematics as a tool, rather than a science in itself, a philosophy, and therefore I thought Iíd either go into astronomy or into actuarial sciences, i.e. insurance.
DeVorkin:Why did you choose astronomy?
Strand:I decided that astronomy would perhaps be a good subject for me. I had already previously been interested in astronomy, in a sort of way as a Boy Scout. For instance — I knew how to orient myself with respect to the stars, on night tours, so I had to know the constellations. This is one of the reasons, I would say, that perhaps I was inclined to going towards astronomy.
DeVorkin:Certainly there would be the economic question too. Did you know that you could get in astronomy at the time, or did it influence you?
Strand:No, that didnít affect me, because regardless of what I took as my major, I was qualified to teach the other subjects, physics, chemistry and mathematics, because I had had sufficient training in those fields.
DeVorkin:I see, so that was always a fallback position?
Strand:Yes. Because the subject of astronomy was a very small subject within the school system. In fact, it was part of physics, and the textbook was very elementary.
DeVorkin:Still you mentioned actuarial work and Iím curious to know if you had any pressure or influence from your parents or anyone else?
Strand:At that time my mother was my only parent, and she let me choose what I wanted. As long as I did well, she felt this was fine.
DeVorkin:What kinds of courses did you take in astronomy, what kinds of studies did you have under Stromgren and did you have other teachers as well?
Strand:No, the only teacher was Elis Stromgren. The courses I took with Stromgren were mostly reading assignments. He taught very little. He taught a few subjects on celestial mechanics, and on the restricted three body problem, which were the subjects that he was interested in. I did some observational work, which was part of the requirements and that was to observe minor planets with Miss Vinter Hansen, or the assistant.
Dick:What instruments did you observe with?
Strand:With a 36-cm aperture refractor. Observations were made with the old eye and ear method, the same way as used by Bessel. You counted the seconds between the passages of the reference star and the minor planet over the micrometer wire.
DeVorkin:Does this account for your first few publications on asteroid orbits and asteroid observations?
Strand:That became part of my requirements towards my Masterís degree, yes, and followed after the year we had courses to acquaint us with what should be taught in the gymnasium.
DeVorkin:Did Stromgren dictate what asteroids you would study? Was there a specific program that he had control over?
Strand:Well, there had been suggested a number of asteroids to the observatory in need of new orbits.
DeVorkin:Assigned by whom?
Strand:They were obtained from the Rechen Institut, then in Berlin. And so, I was given the choice of which ones I wanted to work on, and I selected four.
DeVorkin:There were three papers, probably therefore at least three orbits.
Strand:There were four orbits.
DeVorkin:And these were all on the restricted three-body problem?
Strand:No, these were all on orbits of minor planets.
DeVorkin:So it was two body?
Strand:Well, three body in the sense that you had to include the perturbations by Jupiter.
DeVorkin:Thatís not the restricted three-body solution?
Strand:No. The restricted three-body problem is the one where you have two equal masses moving in circular orbits, and with a third body of infinitesimal mass moving with respect to them. That was Stromgrenís special field.
DeVorkin:I didnít realize that the two masses had to be equal.
Strand:Yes. So then during this study, I decided that rather than just get a Candidate Magister degree, I also wanted to get the Masterís degree at the same time, so I got a double degree when I graduated in 1931.
Strand:A Magister (Masterís) and a Candidate Magister.
DeVorkin:What is the distinction between the two?
Strand:The distinction between the two is that the Candidate Magister is the degree required for teaching in the gymnasium.
DeVorkin:The Candidate Magister?
Strand:Yes. Whereas the Masterís (Magister) degree is meant for those who want to make their profession in the sciences.
DeVorkin:In your last year, 1931, as you worked finishing up your Masterís thesis, you must have been looking for a position or job or thinking of going on for a Ph.D.?
Strand:No, I wasnít thinking of going on for a Ph.D. at that time.
DeVorkin:Then what were the options open to you?
Strand:Well, either teach or find a position for which my degree made me qualified.
DeVorkin:Now, you did teach during this time for a year?
Strand:No, that was later. Right after I got my degree, I was approached by Professor Norlund.
DeVorkin:Whatís his first name?
Strand:Niels Erik Norlund, who was director of the Geodetic Institute.
DeVorkin:How did he hear of you? Through Stromgren?
Strand:Well, he was also a professor at the university in mathematics, and was an astronomer himself, who at one time studied at the Observatory. A requirement towards a Masterís degree was to give a public lecture, and when he apparently knew about it. So he offered me a position at the Geodetic Institute.
Dick:What was the public lecture on?
Strand:The Hertzprung-Russell Diagram.
DeVorkin:Here youíre doing all this positioned and orbital work — you must then have done broader reading?
Strand:Oh, yes. In positional astronomy I had read J. Bauschinger ďDie Bahnbestimmung der Himmelskorper, G. Strucke ďBahnbestimming, Die Planeten und Kometen,Ē and F.R. Moulton ďAn Introduction to Celestial Mechanics.Ē I read quite a bit during those years.
DeVorkin:Had you read by this time works in English? Had you read Eddingtonís INTERNAL CONSTITUTION OF THE STARS?
Strand:I had read part of it. I had my own copy.
DeVorkin:Russell, Dugan, and Stewartís ASTRONOMY?
Strand:I had also read part of it. My textbooks were Newcombe Engelmann, ďPopulare Astronomie,Ē Muller-Pouillet, a more modem text. (I lost the book and do not remember the title).
DeVorkin:What journals were you reading by this time?
Strand:Well, we had in the observatory the Astrophysical Journal, the Astronomical Journal, and others and I did read articles in which I was interested.
DeVorkin:Had you been developing an interest in astrophysics?
Strand:No, not really. Not really as such. But I was fascinated about the origin of the stars.
Dick:Did Norlund attend this public lecture, then? It was after this that he approached you?
Strand:Well, it was practically the next day that I got a letter from him.
Dick:Was he at the lecture, do you know?
Strand:I canít recall. I donít think so. He was a pretty busy man.
DeVorkin:How did you happen to choose to talk about the H-R Diagram?
Strand:Well, I thought it was a subject that other people who were invited to come to the lecture could fairly well follow, rather than talking about a subject in celestial mechanics.
DeVorkin:Is there any possibility that you have your lecture notes, or remember what you talked about?
Strand:I donít think I have those notes any more. I didnít collect my notes at that time.
DeVorkin:The reason Iím fascinated, other than the typical reason that it would be a great document, is that just at that time, of course, the whole question of the evolution of stars was thrown open again. Russellís theory of evolution was no longer believed, yet people didnít know what to do. Could you give me your recollection of the state of evolution in your mind at that point? Could you reconstruct at all what you said to the public?
Strand:No. I think Iíd rather not. That would be really difficult to do. I was also, by that time, a little fed up with the celestial mechanics that I had crammed for Stromgren. When I told him that I was prepared to take the final examinations, which were all very long written exams, Stromgren said, ďWell, I notice one thing, you have not done any work using logarithms. I want you to compute an orbit in the restricted three-body problem. During that time you will not be allowed to use the computers at the observatory.Ē
DeVorkin:Computers being people or machines?
Strand:No, the computing machine at the observatory.
DeVorkin:They were hand-cranked?
Strand:Oh no, electric. We had electric calculators in Ď26, Ď27, and in Ď29 when I first started computing, we had an electric calculator there. I think they had only one.
DeVorkin:What was the size?
Strand:It was electric in the sense of electric mechanical.
DeVorkin:Was it American, Dutch, Danish?
Strand:Iíve forgotten which one it was. Iím sure it was not Danish. But at any rate, after he gave me this problem, I got quite upset about it, because this would set me back some months. So I decided to rent a calculator.
DeVorkin:Sneaky. So it didnít take you months?
Strand:I remember that machine, it was a Madas machine, Swiss made. I took it home and computed the orbit. I got the instructions not from Stromgren himself but from his assistant, Axel v. Nielsen.
DeVorkin:The same one who wrote the biography of Hertzsprung?
Strand:Yes. It was to be a periodic orbit, so you started with a given position, selected a velocity, and computed the orbit by numerical integration. If it crossed an axis under 30 degrees it was a periodic orbit. So I had to do quite a few computations, varying the initial velocities. I had to do it by trial and error, and of course, with a calculator it was a lot easier than doing it with logarithms. It didnít take me very long, about six weeks and I turned it over to Axel V. Nielsen, and Nielsen reported to Stromgren that I had completed the orbit, and that was fine with him.
Strand:I did have some computations with logarithms, in case Stromgren wanted to see any of the computations.
DeVorkin:That is really incredible. Let me just ask one more thing in this area. You went to work at the Geodetic Institute?
DeVorkin:Before you did that, about the same time, Bengt must have taken his Ph.D. It was in 1929 when he took his public defense?
Strand:Yes, it was.
Dick:This is Bengt Stromgren. That was the first Ph.D. to come out of the University of Copenhagen in this century, I believe?
Strand:In astronomy in this century, yes.
DeVorkin:Did you attend that defense?
Strand:Yes, I did.
DeVorkin:Iíd love to have your recollections of it, and also, why were there so few Ph.D.ís in astronomy in the early 20th century from Copenhagen?
Strand:Well, Iím told that Elis Stromgren simply didnít want to have anybody else get a Ph.D. degree. He apparently wanted to leave the field open to his son. I believe Bengt was not more than 12 years old when he got his desk in his fatherís office, to begin his studies in astronomy. Bengt is a very brilliant person and a very nice person. I like him very much, and have been friends ever since I was a student.
DeVorkin:Do you have recollections of Bengt Stromgrenís doctoral defense?
Strand:Yes, I do. I read his thesis, and I used his system for my computations for the asteroid orbits.
DeVorkin:But he immediately went into theoretical astrophysics?
Strand:Yes, he changed to that, and had very close connections with Bohrís institute.
DeVorkin:Which was also in Copenhagen?
Strand:Yes. I had attended lectures and seminars there also.
DeVorkin:But you did not develop an interest in theoretical astrophysics?
Strand:No. I just followed some of the lectures.
DeVorkin:Did modern astrophysics, the kind of thing Bengt Stromgren was going into — the problems with opacities, understanding what the hydrogen content of the stars could be, especially after 1929 and Russellís papers, did this sort of stuff seem to be too unsettled to get into, or was there something else that kept you away from it?
Strand:Yes, I stayed away from it because I preferred to be a practical astronomer, an observational astronomer, and in this sense I think I had many things in common with Hertzsprung.
DeVorkin:Did you know, when you gave your Masterís public lecture on the Hertzsprung-Russell Diagram, that it was called the Russell Diagram at that time?
Strand:It was called the Russell Diagram at that time, right. I called it the Russell Diagram.
DeVorkin:You called it the Russell Diagram?
DeVorkin:Thatís fine, because I was going to ask you more questions about that later, but was there any sense of national pride or personal pride, that made you wonder why it wasnít the Hertzsprung-Russell Diagram at that time?
Strand:Well, to tell you the truth, Hertzsprungís name was not mentioned in astronomical circles at the observatory in Copenhagen.
DeVorkin:Is there a reason for that?
Strand:I think there has been some animosity between Stromgren and Hertzsprung, and so the whole staff did not mention Hertzsprung. In fact, I wasnít aware that Hertzsprung was a Dane, at that time. I had seen his papers. Iíd read some of his papers, but they were in German, and so was his name.
DeVorkin:Thatís very interesting.
Dick:Do you know what the origin of the animosity was between Stromgren and Hertzsprung?
Strand:Well, they were two entirely different personalities.
DeVorkin:Weíre talking about Elis Stromgren in this case?
Strand:Yes, not Bengt. Bengt and I have always been very good friends, and we are always on very friendly terms with each other.
DeVorkin:Letís move on to your move to the Geodetic Institute, unless thereís something else you feel we should cover about your training in Copenhagen.
Strand:No, letís move on to the Geodetic Institute. At the Geodetic Institute, I was told that astronomical observations of longitude and latitude were needed at first order geodetic stations. Some stations for which observations were needed were those in the southern part of Jutland, that had been returned to Denmark after the First World War in 1920, and so I selected a number of stations there for a summer campaign. Each station was furnished with a pier to support a portable transit instrument. Portable in a sense that it was quite a large instrument. A Repsold reversible.
DeVorkin:Three inch? Two inch?
Strand:A three inch aperture. With the instrument mounted on the pier; there was a portable shelter to protect it. We stayed usually two weeks at each station to get sufficient observations. During the first part of the night, I did the transits, and during the second part, I did the latitude observations.
Dick:They were done separately?
Dick:Same instruments, but were the observations in right ascension and declination made separately?
Strand:Well, we made only right ascension observations during the first part of the night.
Dick:It was not a transit circle then?
Strand:No, it was not a transit circle as such, but had a circle for setting altitude. We did the latitude by the Horrebow method, where we observed differentially with the micrometer, the positions between one star north and one south of the celestial pole.
Dick:Were these observations a one man situation?
Strand:I did the observations, and I had three soldiers with me.
Dick:What did they do?
Strand:One was the driver, and one was recorder, and the third one did sort of odd things.
Strand:No, nobody cooked. Denmark still had the system that the government could assign military to private homes, and since this was out in the country we stayed on farms. You paid a nominal charge for your food, but otherwise, the lodging they had to provide.
Dick:You say these were first order stations. What does that mean?
Strand:Well, this is the primary triangulation net that starts with very large triangles.
Dick:These were involved with the very large triangles.
Strand:Yes, these were large triangles, with sides of 40 to 50 km.
Dick:How many of these two week periods did you do? How many stations were you involved with?
Strand:Oh, I was there from — April, May, June, July and August — so I had about ten stations?
Dick:This was 1932?
Strand:Yes, 1932. Not all stations were in Jutland. Some were in other parts of Denmark, mostly in the southern part of Denmark. And of course we traveled with this truck with the whole observatory and set it up at each new station.
DeVorkin:With all of this travel during the summer, how was your personal life developing?
Strand:I was busy!
DeVorkin:Yes, I can imagine. But you were 25 years old — were you thinking of getting married or having a family at that time?
Strand:I was sort of engaged. But this was really something that we had not really quite decided on. Then along came the end of August and I suddenly got this invitation to come to my old school, to take over for my former professor there.
DeVorkin:End of August, Ď32?
Dick:Before we go on to that, can you give us a better idea of the nature and the size of the Geodetic Institute?
Strand:The Geodetic Institute at that time?
Strand:Well, it was a fairly large institute. We had not only to do triangulation. The one who had been doing this work before me was stationed in Greenland, doing the same kind of work in Greenland.
Dick:What was the size of the staff?
Strand:Well, itís hard for me to say because we had several divisions. And we had quite a few military. The military were all officers who were there on either temporary or permanent basis.
Dick:Which division were you in?
Strand:I was in the division that did the astronomical work.
Dick:Do you remember the name of the division?
Strand:Well, — really, it doesnít matter, I donít think it had a name. A member of the same division later became the successor to Norlund, and he did primarily gravity measurements.
Dick:Did you have any direct contact with Norlund during your time there?
Strand:Oh yes. He was very much interested in the astronomical observations.
DeVorkin:Was there any pure research done at the Geodetic Institute?
Strand:No. Not as such. But when it came to finally reducing my observations, I realized that the catalogues that were used didnít have the same positions for the stars. So I got involved with this, and tried to figure out their systematic differences, and reported that to Norlund. Norlund at that time I think was already too much involved with other things. He didnít quite understand what I was trying to tell him.
Dick:Which catalogue had you been using at that time?
Strand:Well, we used the Boss Catalogue, and then of course we had also the catalogues of the Berliner Jahrbuch at that time. These were all bright stars, the fundamental stars.
Dick:So you did not only the observations, you also did the reductions?
Strand:I did also the reductions. For longitude observations we got the time by means of radio, from the Shortt clock in a station just outside of Copenhagen. And so I called in when I wanted to observe, and so they would start to transmit the signals.
DeVorkin:The Shortt clock had the electrical connection?
Strand:Yes, it had electrical connections.
DeVorkin:You mentioned in your autobiographical notes that your first contact with Hertzsprung came when he visited during Christmas of Ď31?
Strand:Thatís right. The reason that he came to visit me was that he was a very good friend of Norlund. In fact, when Hertzsprung got the appointment as professor in Germany, he became automatically a German citizen. And when he then came to Holland, he wanted to get his Danish citizenship back. The Dutch didnít care what kind of citizenship he had, but Hertzsprung was very nationalistic, very proud of being a Dane, and I think it was his grandfather who had come from Germany, but he felt that he was a Dane. So he wanted to get his Danish citizenship back, but since he didnít live in Denmark, which was required by law, it was Norlund who interceded with the Danish king and got him his Danish citizenship back. Norlund was a very influential man in Denmark.
DeVorkin:Was this because of his position with the Geodetic Survey or were there other reasons?
Strand:Well, I think it was his position with the Geodetic Institute, and also the way he impressed people.
DeVorkin:What was your first impression of Hertzsprung when you met him? I take it you met him at a party at his sisterís?
Strand:Well, the first time I met him was in my own house. He came to our home and introduced himself. He asked me what I had done in my studies, and what my future interests were, and I said, I was now involved in this new position at the Geodetic Institute which seemed very interesting to me. And so he invited me to come to a party at his sisterís home, where also Bengt Stromgren was, with his bride.
DeVorkin:Now, at this time you recall that you discussed with him various types of research?
Strand:No, that came later.
DeVorkin:But were you developing an interest to broaden your research base?
Strand:Yes, I was interested in that, but of course I had a problem, in the sense that this job at the Geodetic Institute, when I was out traveling kept me busy all the time, because if we didnít observe, then we measured the tapes that we had for the time passages and there was always a backlog. I did not complete them by the time I took leave to go to the gymnasium. So, I arranged to spend certain afternoons working on the observations that we had made the previous summer, while I was at the gymnasium. But during that summer, I met Hertzsprung again, and he said to me, ďWell, if you have some time to think about doing something else than what you are doing now, letís talk about the possibility of your spending some time in Leiden.Ē
Dick:Hertzsprung was the director of the observatory at that time?
Strand:No, he was the adjunct director because de Sitter was still alive and was the director.
DeVorkin:Why do you think Hertzsprung was interested in bringing you to Leiden?
Strand:Well, I was told by Axel V. Nielsen that he had always wanted to have a Danish assistant, and in fact had invited Axel V. Nielsen to come, but Axel V. Nielsen didnít want to go. He had a feeling that Hertzsprung was sort of a driver, you know, that would exact everything he could out of his assistants.
Strand:Because he was a hard worker himself. He knew Hertzsprung was a hard worker himself, so he expected that his students would also be hard working for him.
Dick:Why was he so interested in a Danish citizen?
Strand:Because he was a Dane himself.
DeVorkin:Was this reputation that Hertzsprung had true? That he was a hard driver?
Strand:No. I would say not. I would say he was only a hard driver as far as he himself was concerned. He would inspire his assistants to work hard, if you understand what I mean by that. He would inspire them to do it. I worked hard. I wanted to work hard. I got into the competition with him. And the other people did too. We competed with each other.
DeVorkin:Now, was this competing seeing how many plates you could measure as a function of time, or how many stars you could observe, or was it more —?
Strand:In anything that you did, it was how much you could do, you know.
Dick:Itís not like he was forcing you to do things, though.
Strand:No, he wasnít. He inspired you to do it.
DeVorkin:But what was the source of the inspiration?
Strand:Well, he was very much interested in what you obtained. He did not want you to work for him. He never asked me to do any kind of scientific work for him. He could ask me to do other things. For instance when he got invited to go to Lick Observatory to observe, he said, ďWould you mind putting together an observing program for me?Ē And of course I was delighted to do that. I can only think of that, and also, if he went on vacation, would I mind looking after some of his correspondence, see that he received it and so on.
Dick:When he brought you to Leiden he did not have an observing program in mind for you?
Strand:Before I arrived, he had written up several programs that I could work on, that he suggested I would be interested in. And I picked the one on binary stars. Another one was the proper motion in the Hyades, which I recall was one that he was very much interested in. But I was interested in the binary stars.
DeVorkin:Could you relate this back to your training with Stromgren?
Strand:In a sense I had, of course, gone through all the theoretical aspects of how to compute binary stars by various methods and so on.
DeVorkin:What telescopes did you have available to you at Leiden to observe binary stars?
Strand:We had the telescope that was similar to the Carte du Ciel photographic telescope.
Strand:The 13-inch. But actually during my first years, all the material was available either from Hertzsprungís earlier observations from Potsdam, or later observations made there by Professor Munch, as well as plates from Johannesburg.
Dick:But you did observe yourself?
Strand:Yes, but none of those observations went into my thesis.
DeVorkin:Now, you chose a photographic program?
Strand:A photographic program.
DeVorkin:Was this common at the time, to do double star work photographically, or was this a new technique?
Strand:This was the technique that Hertzsprung had developed during his years at Potsdam, and so the main material that I worked on was to measure those plates. Shortly before I arrived, a new measuring machine, built in Potsdam had been received, funded by the Carlsberg Foundation. Incidentally, my stay in Holland was based upon funding from the Carlsberg Foundation. I lived, by the way, at Hertzsprungís house. Hertzprung had official quarters, and we were three Danes living together. The other Dane was a physicist who was a Danish consul and businessman.
DeVorkin:Who was he?
Strand:A physicist — his name was Holst Weber.
Dick:How long did he live with you?
Strand:During the whole stay there. We had an old lady as a housekeeper, and we had breakfast and lunch, not always together, because I would be observing at night, or work late at night, and then we went out for dinner together.
DeVorkin:What was Weberís specialty in physics? Was he actively engaged and did you discuss physics with him?
Strand:Yes. He was a close friend of Professor Kramerís, who was a professor of physics at the University. He followed some of the experimentation that was going on in low temperature physics at the Kamerling-Onnes Laboratory; he wasnít much involved. He went there and watched experiments he was interested in, but he really didnít publish anything. He was very busy with his own business. He had a mattress factory, so that kept him busy.
DeVorkin:You were in Hertzsprungís house, obviously in close contact with him. I would like to ask as an aside if he ever talked about his relationship with Henry Norris Russell, during that period or later?
DeVorkin:You know what his relationship was?
Strand:No. I really donít, because if there was any, then itís all in their correspondence. Hertzsprung himself never really said much about the Hertzsprung-Russell Diagram. As a matter of fact, he has said publicly, ďWhy donít we just call the diagram what it is, so people know what itís all about?Ē In other words, whether itís a magnitude spectrum or magnitude color diagram, or something like that.
DeVorkin:Did you hear him directly say that?
Strand:There was an Astronomical Society meeting in Cleveland, quite a few years ago, in 1951, at which there was a colloquium on the Hertzsprung-Russell Diagram, and there was a note from Hertzsprung at that time in which he said that.
DeVorkin:To the organizers of the meeting or to you?
Strand:In a letter.
Strand:No, to the chairman.
DeVorkin:Would that have been Nassau or someone like that?
Strand:Yes, could have been.
DeVorkin:Just to finish out this line, I know that by the mid-thirties there was a move to change the name of the diagram from Russell to Hertzsprung-Russell.
Strand:Well, it was earlier.
DeVorkin:Earlier? Can you tell me who was involved in that, who did it?
Strand:Bengt Stromgren was the first one. I think he did it in a lecture in 1933 at the German Astronomical Society.
DeVorkin:You mean the Astronomische Gesellshaft?
DeVorkin:And this would be published in the Jahresbericht?
Strand:I assume that it was published in the Jahresbericht. (It was published in Vierteljahrschrift, Vol. 68, p. 306, 1933).
DeVorkin:I wasnít that aware of it. What were the next steps, because I thought Kuiper and Bok were involved also to some extent.
Strand:Well, once Stromgren brought it up I think everybody else accepted it.
DeVorkin:Was his influence sufficient in Ď33?
Strand:I think so. And of course the fact that now youíve got the Dutch astronomers involved; they knew what Hertzsprungís contribution was. Although he never himself did much about it, and he never publicized it much. I asked him at one time if he would give me a reprint, and he said, ďWell, Iíll look around and see if I have one,Ē and he found one and gave it to me.
DeVorkin:Was this from his 1909 paper?
Strand:No, the two papers from 1905 and 1907.
DeVorkin:In the photography journal?
Strand:Yes, in Zeitschrift fur Wissenschaftliche Photographie.
DeVorkin:So those he feels are the defining papers, rather than the place where he first published the diagram?
Strand:Yes. You know, one reason why he didnít publish a diagram in these papers? He would have done so, if he was dealing with one population of stars, and not with a heterogeneous set of observations of stars of all kinds, as Russell did.
DeVorkin:Hertzsprung was looking at clusters?
Strand:Yes, he looked at clusters. And there he pointed out the relationship. When he went to Gottingen in 1908 he brought with him a magnitude-effective wavelength diagram of the Pleiades.
DeVorkin:In fact it was his assistant Hans Rosenberg who first published a color-magnitude diagram.
Strand:Yes, well, that was the magnitude-effective wavelength diagram.
DeVorkin:And Hertzsprung shortly after that. Did you know Rosenberg at all?
Strand:No, I didnít. I think, he was dead by the time I came to Leiden in October 1938. Otherwise I would have met him the following December, when I was in Berlin.
DeVorkin:Letís talk about Leiden then.
DeVorkin:First of all I assume it was either Norlund or Hertzsprung who got the Carlsberg money for you, or did you have to apply directly?
Strand:No, Hertzsprung applied. As a member of the Academy, he got the money, and that was something that normally happened. The Academy members, when they asked for funds usually obtained them. Of course with a powerful man to support it like Norlund, there was no question.
DeVorkin:What was the atmosphere like at Leiden? How different was it from the atmosphere for research that you had known at Copenhagen?
Strand:Oh, it was very open. Yes. Very open. And you didnít have a feeling that there was just one boss that handled everything, and everybody should look up to and obey. But that you really worked as a team. And of course there were some very outstanding young students there at that time.
DeVorkin:Who was most memorable in your mind?
Strand:Well, for instance there was A.J. Wesselink. There was Uitterdijk, and another one by name of Martin — these were really the three. The last two died during the war. They both went to Lembang Observatory in Java and were put in captivity by the Japanese when war came and did not survive. In my later period at Leiden, P. Oosterhoff came back from the United States, and he and I became very close friends.
DeVorkin:Oort of course was there and de Sitter.
Strand:Oort, yes, and de Sitter. De Sitter I didnít see much of, but I guess he wasnít too well. And then he died.
DeVorkin:Yes, shortly after you came?
Strand:Shortly after I came. And there was a question of who should succeed him. But Hertzsprung succeeded him.
Dick:Hertzsprung had been the adjunct director of the observatory?
Dick:So when you came, Hertzsprung was pretty much in control because de Sitter was not well at that time, is that right?
Strand:Well, I do not think so. I believe that de Sitter depended more on Oort than on Hertzsprung in that respect.
DeVorkin:This is what I was wondering about.
Strand:Oort was a lecturer, I believe.
DeVorkin:The reason why I wanted to ask that was that Oort was planning to come to Harvard for a summer school, and then de Sitter died, and Oort said that due to responsibilities at the observatory, he could not come. Now, that sounded like he had considerable responsibilities, that he was maneuvering or possibly being considered for director. Was there anything in that, to you knowledge?
Strand:I think there was. I think that he had hoped to become the director.
DeVorkin:Who was it that made the decision, then?
Strand:Well, the decision was made by the university, and I guess the appointment was by the Queen, at the recommendation of the Minister of Education.
Dick:Did Oort ever say anything about being disappointed about not succeeding de Sitter?
Strand:No, not that I know of. I think they worked very well together. I donít think Hertzsprung worked as hard as a director as he perhaps should have done, because he was prone to delegate administrative work to other people.
Dick:And how about de Sitter? What was his style as director, or do you have no direct knowledge of that?
Strand:Very little because I hardly ever saw him.
Dick:Was that because of his illness at the time?
Strand:I really donít know.
DeVorkin:You were talking about the relationship of Hertzsprung Ė-
Strand:— yes, with his assistants.
DeVorkin:You were an assistant?
Strand:I was his personal assistant. He was on very friendly terms with people, very much interested in their work, but did very little formal teaching. In fact, I can only think of one course that he ever taught. It was a course where he used as a textbook one of Ostwaldís Klassiker der Exacten Wissenschaften on meteorites and meteors.
DeVorkin:Is this part of Ostwaldís Klassiker?
Strand:Yes, Ostwaldís Klassiker.
DeVorkin:He did not use any textbooks such as practical astronomy textbooks?
DeVorkin:Campbell had come out with something?
Strand:In fact, he only gave that one lecture series on this book while I was in Leiden. I didnít attend, by the way. I was too busy and I was not that much interested in meteors and meteorites at that particular time.
Dick:Did Hertzsprung prefer not to do teaching?
Strand:I think he preferred not to do formal lecturing, but he liked to talk to people informally. What would happen was that in the evening or maybe as late as 1 or 2 oíclock in the morning, he would come by an office and stand in the doorway and start talking to the person about his work. He did not want to give direction, so he was careful about making any suggestions in that respect, but he just wanted to find out what the person was doing and then perhaps he would ask a question which made you realize that you were on the right or wrong track. He was very clever in that respect, to ask a question that would make you realize if you were using the right approach. And another thing that he would do was, every so often he would post a problem on the bulletin board that everybody had to solve and then come in and tell him.
DeVorkin:Each person had to come in?
Strand:Yes. And it was an honor system. You could not talk to anybody else about it. And he would make a note of who had been there and what time and so on. But he did not want any of his assistants to work for him. He did the most menial work himself, and had great fun doing it. It was sort of a way that he relaxed. For instance, when he did variable stars, he used the eye method of comparisons on the photographic plates, by means of a small magnifying glass. He listed the difference between the comparison stars and the variable star, and later added the epoch. He wrote very carefully, and cut the lists into small strips of paper not bigger than about half an inch high and two inches wide. He had all these strips of papers he would rearrange, and then eventually end up with the data for the light curve. But he would do all this himself. Now, the only ones who would do any kind of work for him would be some of the computers we had. We had two or three civil servants who were computers and they would compute or measure for him.
Dick:What were your duties then as personal assistant? Your title was personal assistant?
Strand:Personal assistant, I did just my own work.
Dick:How many other assistants did he have, and also what was the size of the staff at the time?
Strand:The observatory staff at that time had about 20 people, and that included these assistants that I have previously mentioned like Wesselink and the other ones. They were paid assistants.
DeVorkin:They were observatory assistants, however?
Strand:They were observatory assistants.
DeVorkin:That meant they were regular staff members and worked pretty much on their own research too?
Strand:They worked on their own research, yes. They were actually graduate students with a stipend.
Dick:Was there any other organizational structure of the observatory, aside from the director or co-director?
Strand:After de Sitter died there was Hertzsprung as director, and then there was an adjunct director who was Dr. J. Oort, and then there was also an observator who had previously done transit circle work. They were still doing transit circle work when Van Herk was there, and there was one lecturer Dr. Waltiger, who lectured besides Oort.
Dick:What was the duty of the Observator?
Strand:The Observator was supposed to be responsible for the transit circle observations. But by then he had been there quite a many years and really didnít do much.
DeVorkin:And there was no other differentiation into divisions or anything like that at the observatory?
Strand:No, except that the Hertzsprung group worked separately from the other staff. The other staff was in the main building.
DeVorkin:What was the role of astronomy in the intellectual society around Leiden? Did it enjoy all the support and respect that it wanted or needed?
Strand:I think so.
DeVorkin:What was the role of the director of the observatory himself, was he a public figure?
Strand:No, not in the sense it became later on with Oort as director. Things were different then than at the present time. Public relations meant less.
Dick:How about funding? The funding came totally from the university?
Strand:The funding came totally from the university.
Dick:And there were no problems with funding?
Strand:If there were problems with funding, I wouldnít know about them.
DeVorkin:First you were supposed to be at Leiden one year and I take it you were to go back to the Geodetic Institute?
Strand:Yes, thatís right.
DeVorkin:But then it was extended. Were there any ill feelings back at the Institute?
Strand:That I didnít come back?
Strand:No. I would say that Norlund probably had been in contact with Hertzsprung, and Hertzsprung had said to him that he felt that I ought to stay and continue with the work because I was doing good work and it looked like I was material to become a professional astronomer. We went to the IAU in Paris in 1935, and at that time Norlund said that he had hoped that I would carry out some longitude observations at the University observatory in Copenhagen, because it was included in the geodetic net, and he thought it would be good to have my observations from there. We agreed Iíd do that the next spring. Then that fall, Hertzsprung and I talked things over, about what I had accomplished, and he said to me, ďWell, I think youíd better put all the data together that you have, and write up a paper, and I think we should consider it for a thesis for a degree.Ē
Dick:This was your photographic double star?
Strand:Yes, my photographic double star work. That was in the fall of Ď35.
DeVorkin:A number of questions come to mind here. Was this the first fruit of the photographic double star work, the first published?
Strand:No, Hertzsprung had published his own observations, as a list of observations, and he had done a preliminary study to show Norlundís perturbation in Psi Ursa Majoris. Then later when Van den Bos was an assistant in Leiden, before he went to Johannesburg, he wrote a paper on the same system, but gave a complete study of all the components of the system, and this became a prize paper for a Gold Medal from the Academy in Copenhagen.
DeVorkin:What was uniquely your contribution to the thesis.
Strand:Well, this was the first time that we made a real serious attempt to find out what the intrinsic accuracy of the observations were as demonstrated by the orbits that had been computed.
DeVorkin:Did you compare this to visually determined positions?
Strand:Of course I included the visual observations in it, because there were not sufficient observations in the photographic to compute the orbits of these classical binaries. I obviously had to go back and re-evaluate for instance, Herschelís observations, where he initially measured the separation of the components by means of the diameters of the stars, and that seemed to work out quite well. I spent quite a bit of time on that and it did work out.
Dick:As a point of clarification, your dissertation is the photographic measurements of the six double stars, Eta Cassiopeia etc. published by the Annals Observatory at Leiden.
Strand:Yes, thatís right.
Dick:How did you pick these six in particular?
Strand:I picked these six because these were the six for which I felt that the photographic observations could give us most information.
Dick:Because of the separations?
Strand:Yes, because of the separations. And also because there were sufficient observations of these classical binaries that we could really make a comparison between the visual and the photographic observations. And one thing that came out of it was for instance the case of 70 Ophiuchi because of the debate as to whether that particular system had an invisible companion or not. It had been assumed by various investigators from visual observations, and also from radial velocities, that there was a third companion. But I demonstrated that there were systematic errors in the visual observations which varied depending upon the separation of the components.
Dick:It was really only a binary, not a triple system.
Strand:It was a binary, not a triple system.
DeVorkin:Let me ask about the 1935 IAU. Was this your first IAU?
DeVorkin:Was this then your first real contact with astronomers worldwide?
DeVorkin:You later said that you met van de Kamp there, and Iíd like to know what your first impressions of him were, whether you started hearing about work in the United States at that time, and who else you may have met?
Strand:Well, there is a joke about this that Iíve told several times. The first night at the Paris Observatory, was a very formal affair. Everybody was either in tails and white ties with decorations or tuxedoes, mostly the younger ones, and we were all introduced in the same way as when you go to the White House, where they announce your name as you enter. You feel a little embarrassed about it.
DeVorkin:I remember turning around once to the caller and saying, ďYes?Ē
Strand:And then some of the Dutch astronomers that were there introduced me to van de Kamp.
DeVorkin:Weíve ended a short pause and Dr. Strand has handed me a copy of Hertzsprungís first publication on photographic measurements of double stars, 1914-19, and this is in the Potsdam Publications No. 75, (Potsdam, 1920) and here there are a number of diagrams on page 22 and page 23, showing the ability of the photographic method to detect perturbations and also a very interesting photograph on page 18 showing the effect of local machine vibrations on the drift characteristics — it must have been the telescope at Potsdam.
Strand:Yes, the trail, when they took the trail, the telescope was stationary.
DeVorkin:So this is an important monograph in the history of photographic astrometry?
Strand:Oh yes. Certainly. We were discussing a meeting at the Paris Observatory in 1935. So these Dutch students or astronomers introduced me to van de Kamp, and I made the remark that I had read with very much interest about his fatherís work in a publication, and that I was very much impressed with what he had done, and van de Kamp said, ďWell, my father is not an astronomer.Ē
DeVorkin:Oh, thatís marvelous. In other words, he was so young at this time.
Strand:— yes, he looked so young, just about out of high school. And so I have later said that van de Kamp hired me because I had flattered him so much at that particular meeting.
DeVorkin:Who else did you meet at that time?
Strand:Oh, I met of course, not only there, but also before and after the meeting at Leiden, quite a few of the well known astronomers. I met Russell, of course. I met Shapley. And quite a few other ones.
DeVorkin:Did you talk to Russell at all about dynamical parallaxes? And his general interest in them?
Strand:No. I think we had a session on double stars at which he was present, and there was some discussion going on at that particular time.
DeVorkin:What was the general regard for his techniques of determining dynamical parallaxes, what he called hypothetical parallaxes? I think Hertzsprung used that term too?
Strand:Well, I think Hertzsprung initiated it, already in his early papers in 1905, Ď07. I did some work later in that too in relation to using just photographic observations, to see if you can get the same results as for the visual. Schlesinger was of course a very interesting person to talk to.
DeVorkin:You met him then, Frank Schlesinger?
DeVorkin:He was at Yale at that time?
DeVorkin:Dr. van de Kamp, I know, used Schlesingerís method of dependences.
DeVorkin:Most people swore by that method. Did you use the same method for reduction of position?
Strand:Well, I did it when I first came to Yerkes, because otherwise the amount of computational work would just be prohibitive in getting any results out on parallaxes, so it was a short method for getting results, and of course itís been criticized since because not enough information can be obtained by just using three comparison stars. Perhaps you should use more, but you also had to think of the time when computers were not available.
DeVorkin:What about Hertzsprung? He used the method of dependences in his photographic work?
DeVorkin:Why was that?
Strand:Well, first of all, he had no reason to use it because he never got involved in parallax work. When he worked on his reductions of the plates on the Pleiades, it was done differentially, so there he did not have to use dependences. He used plate constants.
DeVorkin:Was this the same for his double star positions?
Strand:For the double stars we did not used dependences because we had no comparison stars. The orientation was obtained from the trail of the plate.
DeVorkin:Oh, I see. How did you get the perturbation term then without comparison stars?
Strand:Well, simply you assumed that the scale, when corrected for temperature and focus reading, would be the same for one telescope. And perhaps thatís one of the weaknesses of the method, because the internal errors are considerably smaller than the external errors of the measurements because of the change in the focal lengths, and the figure of the objective of the refractor.
DeVorkin:Would you say you were concerned about these problems at the time? Was Hertzsprung also concerned and did you search for solutions?
Strand:No, we did not. That method was so well established at that time that nobody wanted to go to other methods.
DeVorkin:The other methods had not been devised at the time, as I understand?
Strand:Well, they existed but they were very laborious. Plate constants have existed for a long long time.
DeVorkin:Right, and it was just a question of how many terms you used in the plate constants?
Strand:Thatís right. The measurements made on the Carte du Ciel, were done by plate constants.
DeVorkin:You were going to mention Konig?
Strand:Konig described in detail the plate constant method many years ago in HANDBUCH DER PHYSIK.
DeVorkin:Letís talk about your defense. Your defense was delayed a little bit because it took a while to get Hertzsprung and Norlund together?
Strand:Well, not only that, but first of all, I submitted the manuscript in Ď36 in the spring, when I went to Copenhagen to make these geodetic measurements, and at the same time Hertzprung had told me, ďNow, submit the paper to the university, and then tell Stromgren that you have submitted it.Ē
DeVorkin:And then tell him.
Strand:ďAnd then, tell Stromgren that you have submitted it.Ē And of course, I went and told him, and he got furious.
DeVorkin:You told Stromgren before you submitted it?
DeVorkin:So you followed Hertzsprungís advice?
Strand:Yes, of course. I also knew myself what I wanted to do. He immediately told me that I had to get the paperback, from the university, and let him look at it. And I said, ďNo, I will not do that. The paper had been submitted officially and itís at the university to be considered for acceptance or non-acceptance for a degree.Ē That was it. I left his office. Then, of course, they appointed two readers or two official opponents. They were called official opponents. One was Hertzsprung and the other was Stromgren.
DeVorkin:Bengt Stromgren, orÖ?
Strand:No, Elis Stromgren. Stromgren immediately rejected it, without giving reasons why.
Dick:Who was the dissertation submitted to, then?
Strand:To the dean of the faculty. So it was an official record. And so Stromgren rejected it and Hertzsprung accepted it, and it was up to the faculty to decide what to do, and it was agreed to appoint a third member to the committee, and that was Norlund. Norlund, who had some credentials within the field of double stars from his previous work, accepted it, and so it was two against one. So it was up to the faculty to take positions, and this was a rather difficult situation. They called Hertzsprung from Leiden to come to a faculty meeting, where they were going to decide whether it should be accepted or rejected. And of course Stromgren being the only professor of astronomy, it was a rather awkward situation for the faculty. But the faculty also knew Stromgren pretty well.
Dick:When you say, ďthe faculty,Ē who do you mean?
Strand:The faculty consists of the professors in the natural sciences, mathematics, physics, chemistry, and astronomy. The two Bohr brothers, Niels Bohr and Harald Bohr were members, and some of my former professors.
Dick:How many people in all, would you say?
Strand:I couldnít say how many people went to a faculty meeting. Thatís a secret meeting. But just before the meeting, as they were going in, Stromgren turned around to Hertzsprung and Norlund and said, ďI will not vote against the dissertation, and withdraw my objections, under one condition, that I will not be one of the official opponents.Ē Well, the two of them said, of course, that was perfectly agreeable to them. That was Stromgrenís way of getting out of it. So it was accepted in early Ď37. Then it had to be printed.
Dick:Did it not come to a vote by the faculty then because of this?
Strand:I donít know if it came to a vote of the faculty. I was never told that. Because at the meeting, the two that were appointed said they accepted the paper, and the third would not say anything.
DeVorkin:Where did Bengt Stromgren stand in this? He was on the faculty, wasnít he?
Strand:No. He was in the United States.
DeVorkin:Oh, heíd gone to Yerkes?
Strand:He was at Yerkes by then. And he was not a professor in Copenhagen until his return.
DeVorkin:Heíd gone to Yerkes on leave in the beginning, I know, and he went back to Copenhagen in Ď38 or Ď39.
Strand:He went back in Ď38, thatís right.
DeVorkin:During your years in Leiden, through Ď38, did you have every reason to think that you would go back to Copenhagen? Is this one of the reasons why Elis Stromgren objected to your thesis, because he didnít want you to replace possibly his son?
Strand:Well, he a priori didnít want anyone to get a degree except his own son.
Dick:Even though his son already had one, it didnít matter.
Strand:No. It didnít matter.
DeVorkin:It was his position after the degree that was important.
Strand:And nobody got a degree until Bengt got back.
DeVorkin:Thatís fascinating. How would you characterize your Leiden years? What were your goals at Leiden? Did you wish to stay at Leiden?
Strand:No, I didnít want to stay at Leiden, absolutely not. My idea was that if nothing else happened, I would like to have an opportunity to go to the United States first to see whatís going on, and I just felt that America was the country where astronomy was really happening. I wanted to go there at least for a period, and then eventually if nothing happened, go back to Denmark and continue in the geodetic service. Either that or go back to teaching, one or the other. Whatever I felt that would attract me most. And I think if Iíd gone back I would have done very well.
DeVorkin:What was your feeling about why the United States was the place to go at that time? Was it through talking with van de Kamp and others about what they had, or reading the literature?
Strand:Well, it was pretty obvious from the literature what was happening in the United States. All the big names were there. And when we had the meeting in Ď35, that certainly impressed me with what was going on in the United States. Shapley especially, although it was a little irritating, hearing at the meetings from time to time, his remark about ďwe at Harvard have done so and so —Ē
DeVorkin:ďWe at Harvard,Ē that was his term?
Strand:Yes, it usually was.
DeVorkin:Shapley certainly by his personality was always outspoken.
DeVorkin:What kind of attention did Russell get? Was he quieter?
Strand:Well, no, I wouldnít say he was quieter, because he always had something to say — and this happened later on in his life too — you would be at an astronomy meeting here in the United States, and he had a comment on every paper that was given. And a good comment, not just that he wanted to say something.
DeVorkin:Did he comment on your papers?
Strand:Yes, he would comment on my papers, and Iíve been very happy about what he has said about them. After I came to the United States, I met him many times.
DeVorkin:I know in the late thirties Zdenek Kopal started criticizing some of the rough characteristics of Russellís method of reducing eclipsing binary observations. Did you follow that? Did that develop into a generally known controversy?
Strand:Well, it seemed for a while that Kopal was sort of trying to get support for his ideas by talking to various people. If you look at his papers from that period, he always thanked people for help, for having carefully read his paper, or made comments, which he found invaluable in writing the final paper, and so on. Youíll find this in his publications.
DeVorkin:How would you characterize Russellís contributions to double star astronomy?
Strand:Well, I think he made important contributions as he did to so many other fields.
DeVorkin:True. Iím concerned with the field that you know best. Heís characterized as making the first rough approximations, getting data out efficiently.
Strand:Yes. Well, there again, this must be looked upon keeping in mind of the availability of computers at that time. We did not have the techniques that we have now. You can program almost anything now and do almost instantly things that it took us long times to do. For instance, if I did Least Squares solution with seven unknowns, that was a major undertaking. And you had to make all kinds of control computations, in order not to end up with something wrong. My goodness! I mean, it might take almost a week to do a solution of this kind, which you now can get by the f lick of a switch.
DeVorkin:Thatís certainly understandable. Kopal said it was time for a change, though, by the late thirties.
Strand:Yes. I agree with him on that. I donít think that he always used the most diplomatic way of doing it.
DeVorkin:Did you ever see Russell react to Kopalís criticisms at a meeting or anything?
DeVorkin:There were never any confrontations at meetings?
Strand:No, I didnít see any. I saw both of them several times at the neighborhood meetings that Schlesinger had at Yale, which were always very interesting and inspiring.
DeVorkin:Kopal was at Harvard at that time?
Strand:I think he was at Harvard, yes.
DeVorkin:Van de Kamp became the director at Sproul in Ď37?
Strand:Yes, thatís right.
DeVorkin:Was he instrumental in bringing you to Sproul or did Hertzsprung get involved?
Strand:No, Hertzsprung was not involved at all.
DeVorkin:It was your decision?
Strand:No, it was van de Kampís decision. Van de Kamp invited me to come as a research associate at that time.
Dick:How did he invite you, by letter?
Strand:By letter. I had sent him my thesis, and he said he was very impressed with the work, and then he wrote me later that he understood I had plans about coming to the United States, and would I first then come to Sproul Observatory. I said, well, I did have plans to go to Lick. But if he had something more definitive I would rather do that.
Dick:Were you replacing someone at Sproul or was this a new position?
Strand:I was replacing in some sense, John Hall, who was going to Amherst.
DeVorkin:What was the offer from Lick?
Strand:Well, I had been invited to come if I had a fellowship.
DeVorkin:A Lick fellowship?
Strand:I had the promise of a fellowship from Denmark.
Strand:No, this was a different foundation called the Rask-Orsted Foundation, named after the two famous Danes, the philologist Rasmus Rask and the physicist Hans Christian Orsted.
DeVorkin:What was that, a yearís fellowship to do observations?
Strand:Yes, with an option for renewal for a second year.
DeVorkin:That must have been quite an idea, to use the 36-inch. Could you explain your difference of interest in Sproul and Lick? You chose Sproul because it was more permanent?
Strand:Yes, I felt that I wanted to go to Sproul first, and then eventually perhaps go to Lick. Since Hertzsprung had already done work with the 36-inch, I thought I would try out the 24-inch at Sproul Observatory.
DeVorkin:That was the largest telescope youíd used to that date?
DeVorkin:How did you feel leaving Europe?
Strand:It felt fine.
DeVorkin:Were you married at this time?
Strand:No. I was a bachelor, and it felt great coming to the United States. After two weeks I felt perfectly at home — which I never did in Leiden.
DeVorkin:You didnít feel that in Leiden?
Strand:No. It was different — well, I think, the attitude of the people is different.
Dick:The staff people or people in general?
Strand:People in general. The Dutch are more reserved. Theyíre not as open as people in the United States. This is more my way of life.
DeVorkin:How was your English at that time? Was it better than your Dutch or worse?
Strand:Well, about the same, I would say. I spoke fairly good Dutch but I had an accent, as I also had in English.
Dick:Where had you learned Dutch and English?
Strand:Dutch I learned when I was in Holland. I had pretty good schooling in languages. English was my first foreign language, so I was pretty fluent in English when I came to Holland.
DeVorkin:What was your first impression of the United States? You say you felt comfortable quite quickly. Did you do any initial travels up and down the East Coast visiting other observatories?
Strand:Yes I did. I mentioned that I went to the neighborhood meetings at Yale.
DeVorkin:Did all of them meet at Yale? Didnít they wander around a bit?
Strand:No. Schlesinger hosted these meetings. Of course I went to New York several times, and the New York meeting in Ď38 was my first in this country.
Dick:This was an IAU meeting?
Strand:No, it was an AAS meeting in New York. I went to the Stockholm IAU meeting.
DeVorkin:You did, in Ď38?
DeVorkin:We havenít talked at all yet about the growing war in Europe and people seeing what was happening.
Strand:I was glad to get away from Europe. In fact, I was very nervous, because you remember in September we had all this business of Chamberlain and ďpeace in our timeĒ happening. I came to the United States in October. I could have left earlier, but after the Stockholm meeting in August. I decided Iíd go back to Leiden for a month to finish the various things I had there, so I left — I had cleared everything. At that time, I began to regret that I had delayed, because of the events that were happening, so I was glad when I left early in October. There was no war at that time.
DeVorkin:Right. But it was coming.
Dick:Was this a big concern among the Leiden staff?
Strand:Yes, it was a concern by everybody. After all, you heard all this over the radio, these gatherings of Hitler, his shouting, and how the German people reacted to it.
DeVorkin:What was Hertzsprungís reaction to it?
Strand:Oh, he was very much against the Germans! Very much so.
DeVorkin:Letís talk about Sproul. What were the conditions when you got there to continue your double star research? Was there a camera suitable for the double star work?
Strand:No, there wasnít a camera, but I adopted the one that they had there. There were no objective gratings that I needed for the telescope, but I had them made. I started initially making them myself, and van de Kamp was very cooperative in buying the material for the gratings, which were aluminum, and I worked in the machine shop myself to make the gratings, until one of the instrument markets got interested in making them.
DeVorkin:How many did you have to make?
Strand:Four gratings to provide one, two, three and four magnitudes differences between the central image of the star and the first order spectrum respectively.
DeVorkin:Did you have teaching duties in the beginning?
Strand:No, not in the beginning, but later on I taught from time to time a course in celestial mechanics.
Dick:There had been no photographic double star program here up to this time?
Strand:There had been no double star program up until then, only parallax work, at Sproul.
DeVorkin:Aitkin and others were certainly doing double star work at Lick but they were all visual.
Strand:All visual work.
DeVorkin:Did you correspond with Dugan at that time? Did you work with R.S. Dugan at all? He was doing double star work and using photometric techniques.
Strand:Well, I met him, but it had really no relation to my research, as his was eclipsing binaries. My photometry was, that I could measure the magnitude differences between the components because of the gratings. But that was an eye estimate, similar to the variable stars method, and had an r.m.s. of 0.06 magnitude. I liked Swarthmore. The campus was very nice. There were quite a few young people, also research associates. They were in philosophy, physiology and biology. And I got a nice small apartment not far from the campus, and the people I stayed with became very close friends, throughout their life.
Dick:What was the size of the Sproul staff at this time?
Strand:Well, letís see. Van de Kamp was an associate professor, and then there were three additional professors. Two were Pitman and Marriott. Both had been working with John Miller, the previous director, on solar eclipses, but they were now teaching. Pitman was also the mayor of Swarthmore, which added to his duties. The third professor was Kovalenko. He stayed for a year after I arrived, and then he retired. He participated in the parallax work.
DeVorkin:Had he been there for a long time?
Strand:He had been there for a number of years. He was independently wealthy, through his wife. Some of the students did observational work, but that was the staff. And we had a secretary jointly with the math department.
Dick:The people you stayed with who became your very close friends, were they in the sciences?
Strand:They were dentists. The lady who owned the house was a retired dentist. Her husband who was dead had been a dentist, and a professor at the dental school in Philadelphia. He had also at one time been dentist to the Emperor of Brazil. This has recently been written up, about the dental school in Philadelphia at the University of Pennsylvania. Did you read about it?
DeVorkin:No, but I know itís a very good school.
Strand:Her one daughter was a dentist and married to a dentist. The whole family lived there. They had a big house and it had been divided up, and I had a small apartment, and I became just like one of the family.
DeVorkin:Did you find that the Swarthmore community was open and friendly to you?
Strand:Very much so. Most of my friends were people who were friends of my friends, and most of them were with Du Pont, and commuted to Wilmington from Swarthmore where they lived. They had quite high positions, and some of them were graduates in chemical engineering from Swarthmore College.
DeVorkin:Did you have contact with Vyssotsky at the University of Virginia?
DeVorkin:What was Vyssotskyís relationship with van de Kamp, did they have cooperative programs, that sort of thing?
Strand:Well, I think they differed. They differed in the sense that Vyssotsky was then more interested in spectroscopy, and he did marvelous work. He discovered a lot of red dwarf stars, with his objective prism spectroscopy, which he did with a small (10-in) refractor at the McCormick Observatory. I donít think he was very much interested in parallax work.
DeVorkin:I do know, at least from Wesleyan, they had quite a few McCormick plates, especially of Barnardís Star, and I know that van de Kamp was working on Barnardís Star about that time, beginning his work. And Iím curious as to why Vyssotsky was taking pictures of Barnardís Star also. Iím wondering what contact you had or what interest you had in van de Kampís development of his astrometric binaries?
Strand:Well, van de Kamp developed his program on the nearby stars.
DeVorkin:Nearer than five parsecs?
Strand:No, not only nearer than five parsecs, that wouldnít be enough for a program. But all the various nearer stars, and of course he was trying to see if he could find perturbations. Now, why the Barnardís Star plates from McCormick ended up at Wesleyan I donít know. They were not necessarily taken by Vyssotsky, there were other astronomers at McCormick involved in astrometric programs.
DeVorkin:So you knew nothing of any program that Dr. van de Kamp had tried to develop interest in at other observatories to increase the amount of data that would be available?
Strand:No. The other observatories doing parallaxes at that time pretty much stayed with the programs they were pursuing.
DeVorkin:This would include the East Coast observatories like Allegheny?
Strand:Yes, Allegheny had its programs, and much of this was still programs from the Schlesinger period. Wesleyan has its programs, and that was it.
DeVorkin:So the double star work really was concentrated at Sproul?
DeVorkin:On the East Coast?
Strand:Thatís right. The relative positions that I did and the work he did on the binary stars for determining mass ratios. So there was common interest as you see.
DeVorkin:Did you work together on things?
Strand:Oh yes, of course we did, planned the programs and discussed the results and so on. And van de Kamp was very helpful in seeing that I got support to have assistants. I had an assistant throughout my years there.
DeVorkin:As you were developing the double star program for mass ratios and orbit determination, Iíd be curious to know what selection parameters you had for this, since you were doing wider pairs than van de Kamp.
Strand:Van de Kamp was also working on the wider pairs to obtain the mass ratios.
DeVorkin:So he didnít limit himself?
Strand:No, he didnít limit himself to close binaries. And of course we were both trying to see if we could find dark companions. Some of this was successful, some of it was not.
DeVorkin:What were some of the cases that werenít successful?
Strand:Well, mine was 61 Cygni, but a successful one was Zeta Aquarii, which recently has been observed, measured by the new method of speckle interferometry.
DeVorkin:Who measured it with speckle interferometry?
Strand:McAlister, at Georgia State University, who makes his observations at Kitt Peak.
DeVorkin:That is quite interesting.
Dick:Where do you stand on the Barnardís Star controversy?
Strand:Iím neutral on that point. Not for reasons of my relation with van de Kamp, but simply because he has a point, that he has done so many observations of it over such a long period of time, and we have attempted to do it at the U.S. Naval Observatory with the 61-inch, and have not been able as yet to say yes or no, because itís a tricky problem. You see it is not only a matter of measuring Barnardís Star against a number of background stars. For these background stars, you have to know their proper motions very accurately, and this makes it very difficult. You cannot measure the Barnard Starís perspective acceleration if you donít know this about the background stars. So it takes quite a few years of observations, and Bob Harrington has said at times, yes, he agrees with van de Kamp, and then he says, no, he does not agree. Right now he says yes, he agrees in one coordinate but not in the other. Observations must be continued.
DeVorkin:Do you think the Space Telescope should be able to see companions?
Strand:With the Space Telescope youíll have difficulty because these are long range programs, and I donít think that long range programs will be considered on the Space Telescope. There are too many other things that they want to observe. That makes it difficult, but some of the companions might be visible.
Dick:Positional astronomy in general?
Strand:Positional astronomy is going to be very tricky, and in fact I think in some respects itís not going to be better than what you can get on the ground. For the same effort.
DeVorkin:Is that because of the pressure to do other things?
Strand:Not only the matter of pressure to do other things, but the inherent accuracy that theyíre going to have.
DeVorkin:Theyíre saying seven ten thousandths of a inch, or seven thousandths of a millimeter?
Strand:No, theyíre talking about two milli-arc second accuracy, and this is what can be obtained now with either of the new methods that are going to be used at Flagstaff, using fine grain plates, or using a CCD.
DeVorkin:You think theyíre going to obtain that to two milli-arc seconds with the Space Telescope?
Strand:I couldnít say. I have not at all been involved in that phase. So far, we havenít gotten into estimates of what can be done with instrumentation and so on. Maybe we should reserve that for another time, but I did participate in writing the Kitt Peak proposal for the Space Science Institute.
DeVorkin:Yes, weíre getting too far ahead. You mentioned that through the period Ď38-í42 van de Kamp worked hard to get you support, and it sounded like he got you the support you needed.
DeVorkin:I wonder if you could name a few of the assistants who were especially good in what they went on to do, unless we already knew of them.
Strand:They were Janet De Vilbiss, and Virginia Burger.
DeVorkin:These were assistants?
Strand:Yes. They did a lot of the measuring and computing for me. In other words, the routine work. They did not become professional astronomers. But they were very good. They were college graduates, one from Wellesley, the other one Iím not sure, although I think she was also from Wellesley. She went later to Lick Observatory for a period before she got married.
Dick:So they were graduates in astronomy?
Strand:Yes, they had studied under John Duncan at Wellesley.
DeVorkin:How would you characterize your four years of working at Sproul? Very satisfying? Did you think of it as a long term career?
Strand:To stay there?
Strand:No, I did not. I certainly didnít have the feeling that they were going to open up the field. Aydelotte had been the president, and the new president was John Nason, also a Quaker. I donít think he had much real interest in the sciences. And I know that when Kovalenko left as an assistant professor, I was not appointed an assistant professor, because he did want to create another permanent position. At a later date perhaps if Pitman or Marriott had retired, that would have been a different situation. But I was independent and unmarried, and therefore I could spend my time on my work without having to worry about economic problems.
DeVorkin:You left Sproul for Army service?
DeVorkin:What were your motivations? Aside from what we can well imagine. You did volunteer or were you drafted?
Strand:I was drafted but then volunteered in a sense, the same way as Martin Schwarzschild did. We both wanted to fight Hitler. Neither of us could volunteer as such but had to be drafted because we were not citizens. I was a year short of being a citizen.
DeVorkin:What did you do in the Army? You volunteered after you were drafted?
Strand:No, I was drafted. But in a sense I was a volunteer. I could have stayed on as a civilian, and Schwarzschild could have done the same thing. If there had been letters from the president saying that our work was essential, should be continued, and so on, we probably could have stayed on. But I didnít want to.
DeVorkin:What did you want to do? Fight Hitler but in what way? Did you want to get in the trenches?
Strand:If necessary, yes.
DeVorkin:But you ended up doing something that was very much part of your background. Iíd like to know what the selection process was in the Army and then the Army Air Force.
Strand:All these things at that time happened more or less accidentally.
More or less accidentally. After I got inducted, I went into the Quartermaster Corps. I was at Camp Lee, Virginia, and I had a friend there who was a lieutenant colonel, and he felt as I did, that the Quartermaster Corps was not a very inspiring outfit. So he said, ďWhy donít I see if I can get you a transfer into the Air Corps?Ē Sure enough, I ended up in the Air Corps in Atlantic City, and waited there to get transferred into some field, and in that process because of my educational background and also previous military training they first used me as a drill sergeant, which I got a little tired of. You know, itís bad enough to have basic training, but to be a drill sergeant of basic trainees is worse. If you have a platoon of 30, you work 30 times as fast and hard, because youíll be up front and down at the rear and so on, back and forth, seeing that everybodyís doing the right thing.
So after a couple of weeks I lost my voice and I walked into the squadron room and there I met another fellow whom I knew, who was a lawyer, who told me that he was going to resign, because he had a farm in New York state, and would I like to have his job? I said, ďWhatís your job? ďWell, Iím the court clerk here,Ē he said. ďWell, I know nothing about law,Ē I said. He said, ďHell, law in the Army only consists of using this little book,Ē and he showed it to me. ďFill in the names here and the charge there, on the forms that are available and so on, so thatís an easy job.Ē I said, ďAll right, Iíll take it,Ē so I took the job. Then on one weekend I was back at Swarthmore. I ran into one of my former friends there who was a professor of biology, Lawrence Irving. He had just received his commission as a major to go to Eglin Field, Florida, to be in charge of a department of physiology. He said, ďIím taking several of my people from here. Why donít you get a transfer and come to Eglin Field?Ē I said, ďYou can arrange that?Ē And he arranged it through Detlev Bronk, who was the Chief Assistant to the Surgeon General of the Air Force. So in no time I was out of Atlantic City and at Eglin Field in his department. And then a problem came up in navigation. They needed some new simplified tables for a computer for polar navigation, primarily to observe the sun.
Dick:Was that at Eglin Field?
Strand:At Eglin Field. And so I got involved in that. The Commanding General was very much interested in navigation, and there were a lot of things he wanted to know about. They knew I was an astronomer, so I had to come over and enlighten him on these various subjects and also, when the computer was designed, I had to present it to him. I knew him very well. In fact, I went on several missions, although normally as an enlisted man you were not supposed to fly on missions as a navigator, but I flew with a bombardier who wanted to learn navigation so the two of us worked together on that.
DeVorkin:Where were the missions?
Strand:Almost to anywhere in the United States. With B-17s. And then one day I went into the headquarters building, and met accidentally Edwin Hubble.
DeVorkin:He was running Aberdeen?
Strand:He was at Aberdeen in charge of ballistics, and he came to Eglin to tell about the ballistic cameras that were planned to be installed at Eglin Field. We talked about this, and as I left him, there was an old colonel that I later on had a lot of trouble with, who came and grabbed me by my shoulder and said, ďWho the hell are you? Where do you know this man?Ē I told him that he was an astronomer from the West Coast and I was an astronomer from the East Coast and we knew each other. So he said, ďWell, come with me. You have to come in and sit in on this meeting.Ē I went in and sat in on the meeting, and Hubble started explaining how these cameras worked, and he could see that these people didnít understand a word of it. After a while he said, ďI think Dr. Strand here,Ē (referring to me Buck Private Strand) ďknows more about this field than I do!Ē
DeVorkin:What kind of cameras were they?
Strand:Well, they were cameras that were set up in two stations, to measure parallactically the trajectory of a bomb or the flight of an airplane across their fields.
DeVorkin:Was there anything interesting about the optics in the camera?
Strand:The interesting thing of the optics was that you used photographic plates in day time and still didnít get black plates.
DeVorkin:Very inefficient. Long focus?
Strand:No, short focus, wide-angle cameras.
DeVorkin:So they were good systems?
Strand:Oh yes. They were using the system at Aberdeen, and the Air Force wanted to have a set at the Air Force Proving Grounds because we ran all kinds of bomb ballistics and flight test performances and so on.
DeVorkin:Who designed and built these cameras?
Strand:They were built at Aberdeen. They had various contractors for the special lenses for them.
DeVorkin:I know that Yerkes and Harvard had optical design bureaus that were working for OSRD at the time.
Strand:Yes, well, that was too early in the game to get them involved. Actually, what we got were Goertz lenses that were somehow scrounged from somewhere I donít know where. The cameras were used with the so-called Edgerton lights on the airplanes or bombs. These are bright light pulses that emit only for a few milliseconds, and these were synchronized with the shutters over the cameras on the ground so they were open only for the same duration of a few millisecond for each exposure.
DeVorkin:I see. Milliseconds?
Strand:The camera had to be synchronized with the pulses.
Dick:Pretty good technology for that time.
Strand:Yes. Well, to make a short story, I had already my papers in for a direct commission, and so they were expedited, so I could start assembling the personnel for this project. So I went to Aberdeen as a second lieutenant, and not only worked with the people there in the assembly of the equipment but also finding the personnel.
Dick:Were you the head of the department of navigation by this time?
Strand:Yes, I was made head of the department of navigation.
Dick:After you went to Aberdeen?
DeVorkin:There were a number of astronomers working at Aberdeen at that time in addition to Rubble. Steam and —
Strand:Yes, Steam was there, and also Dorrit Hoffleit, Bidelman, Karpov and Zug. Zug was involved primarily in the measurement of the plates, and we lacked a measuring machine for our setup, so we got together about this problem. He suggested I get a machine either from Sproul or some other observatory, but I was unsuccessful, so we decided at Eglin Field, we should visit David Mann at Lincoln, Massachusetts.
DeVorkin:Oh, yes, I know that company.
Strand:At that time he was really the only engineer there. So I went there with one of our officers from Eglin Field who knew of him, from being a student at Harvard. We went and saw Mann and inquired about building a measuring machine. Well, he said, ďI want to be sure that you get the right kind of machine, so let me make a mock-up in wood, and bring it to Aberdeen, and you and Dr. Zug work with me on the design of the machine.Ē So we designed the first Mann machine.
DeVorkin:This is the two coordinate measuring machine?
Strand:Yes, the two coordinate measuring machine. Actually we had only provision for measurement in one coordinate.
DeVorkin:But the basic design is of the Mann, machine we know?
Strand:Yes, thatís the Mann-Zug-Strand measuring machine!
Dick:So that was the first one?
Strand:That was the first one, and it went to Eglin Field, and I had a former student of mine from Swarthmore transferred from the Weather Service to Eglin Field, had him go through OCS and came back as a 90 day wonder to measure these plates, and also be one of the technical officers of the station.
DeVorkin:Who was that?
Strand:Peter Morris was his name.
DeVorkin:He didnít go on in astronomy?
Strand:No, he got a Ph.D. in physics after the war, and got involved in the nuclear reactors.
DeVorkin:The ballistic camera project — how much time did you spend there in directing the project, and how successful was it?
Strand:It was very successful. I only supervised it. I couldnít run it myself. I built up the whole staff of people. Since we did a lot of electronic work in connection with the project, I had to get the electronic technicians together, and also I needed officers. They came down as privates to Eglin Field and were sent off to officersí school, with the Generalís approval, and they came back as officers and worked on the project. And we did very well. We worked also in cooperation with Hubble. For instance, when we had a special bomb, I think it was a 30,000 pounder called the Tall-boy that was going to be tested at Eglin Field, Hubble and I spent quite some time together on that. He sent his people down. We ran the project and worked together on it very well. Only one thing with Hubble was that he got very disappointed when I got promoted from lieutenant to captain, because from old times he wanted to show his Oxford days and called me ďleftenant.Ē So he couldnít call me ďleftenantĒ any more.
DeVorkin:He was definitely an Anglophile. Did you do any ballistics testing of captured V-1s or have any contact with captured material?
Strand:Yes I did, but we didnít do any ballistics on the V-is, in the sense of using ballistic cameras, because they were flown over the Gulf of Mexico. And there we had a problem, because they were not too reliable. Sometimes they would make an 180 degree turn. So we had to have fighter planes follow them to see what they did.
Strand:Yes, the V-1s.
DeVorkin:They made 180 degree turns?
Strand:Yes, on occasion.
Dick:If they did that, the fighter bomber would shoot them down?
Strand:Well, one of them ended up in the barn of some farmer, some 200 miles north of Eglin Field. However, they had no explosives in them. But I had a solution to checking their range.
DeVorkin:What was that?
Strand:We got the Navy to send dirigibles down to hover over the Gulf of Mexico, while we were testing.
Dick:What did that do?
Strand:So they observed the impacts, and got the range of the V-1s.
Dick:These results of the ballistic camera program were the kinds of results, I take it, that were used but not published, is that right?
Strand:Yes. They were used but not published. No, never published.
DeVorkin:How many of these measuring engines were eventually built by David Mann?
Strand:I would say initially Mann said that he wanted to make at least three, but I think he decided on making five machines.
DeVorkin:After the war did any of these machines get to astronomical observatories?
Strand:Well, we only had one. But he wanted to make them for other purposes. Yes, he followed these machines. He said that once he had built a machine, although he sold it, it was still his property, and would visit his machines and see how they were doing. The one at Eglin Field was surpluses I know. They didnít continue ballistic work after the war.
Dick:When you say three to five of them were made, over what period do you mean?
Strand:Well, I think he started initially building three. And then, before the end of the war, I think he had five machines made, I donít know what he did with them.
DeVorkin:So you donít know where they are now?
Strand:I have no idea where they are now.
DeVorkin:I remember I used a two coordinate machine and enjoyed it very much.
Strand:Was it a fully two screw engine machine?
DeVorkin:Yes. That was already in the mid-sixties.
Strand:Well, right after I came to the Naval Observatory, we procured one of these machines, a two screw engine. It was modified to read-out on punched cards. Time Service already had a Mann machine.
DeVorkin:Very very nice.
Strand:Right after I came to the Observatory. When I said I supervised the ballistic cameras, well, I did, in a fashion. When there was something really hot going then I would be available. But I spent a lot of time flying.
DeVorkin:I wanted to ask you about that. You became a rated navigator in July of Ď44?
Strand:Yes. I flew B-29s.
DeVorkin:As a navigator?
Strand:Yes. I flew also in the position of the bombardier, because we were only doing token bombing. Sometimes we dropped bombs, but whether I was exactly on the spot, that was a different story, simply getting rid of the bomb for a simulated mission.
DeVorkin:Did you have your citizenship by then? You must have.
Strand:Oh yes. I had my citizenship before I got commissioned. It was necessary.
DeVorkin:What did it take to become a rated navigator? What does that mean?
Strand:Well, a rated navigator normally would go to school for about 9 months to a year, but you could circumvent that by having performed the necessary flights, knowing your Morse Code, knowing how to read the weather map, and knowing navigational procedures, which you had to have certified by a navigation school. So I went to school with two of my fellow officers, and they did it out of curiosity and to keep me company. One was a bombardier. The other one was a pilot. We went to school together in Hondo, Texas, for ten days.
DeVorkin:Where in Texas?
Strand:Hondo. They had a navigation school there. And it turned out that the instructor there knew less about instrumentation than we did, or I did.
DeVorkin:Let me ask you not only about instrumentation but techniques. Did you find that the navigational techniques were optimal for the different aircraft you were flying? Did you see the need for different types of techniques? Did you institute any improvements in reduction procedures or instrumentation?
Strand:Well, I think the reduction procedures were there, except for the polar navigation, where I had made a special computer, but for ordinary navigation, we had the HO 218 publication, I believe it was, which was ample. I got so proficient that I could make a three shot position including reduction, in about three minutes. So in that respect there was really no problem, as far as I was concerned, because I knew the basics behind navigation. Most of the navigators knew the procedures, but did not always know why they were following them.
DeVorkin:Thatís why I was asking if you saw better ways to institute procedures?
Strand:Well, there was very little. We had so many new instrumentations that we had to try out, either to accept or reject, for operational suitability — there was not very much time to sit down and speculate on where you could improve on procedures. It was hard work.
Dick:Now, the Air Almanac came into being too at the beginning of the war.
Strand:We had the Air Almanac, yes. One of the things I became involved in also was survival navigation. Thatís why I worked quite closely with Wallace Eckert. He was at the Naval Observatory, and I came there several times.
Dick:He instituted the Air Almanac, didnít he?
Strand:Yes, he did.
DeVorkin:Thatís interesting. I thought he was always at IBM.
Dick:No, he was at the Observatory for, I believe, two or three years during the war.
Strand:He came from Columbia to the Naval Observatory to be head of the Nautical Almanac Office and prepared the Almanac, and did a good job on that.
Dick:Did you have any interaction at that time with the Almanac office?
Strand:Oh yes, I did, on survival navigation.
Dick:And who in particular there?
Strand:Eckert. Of course, I couldnít come to the Naval Observatory as an officer and go directly to Eckert. I had to see Commodore Hellweg first.
Dick:Oh yes, the superintendent.
DeVorkin:Why was that protocol?
Dick:Can you give me more details about your interaction with Hellweg and Eckert at this time?
Strand:Oh, Hellweg, I really didnít have any interactions with him. He was just telling sea stories, and he told the same story over and over again, whether it was true or not. He had told it so many times that he believed it himself. And you had to humor him and listen. That lasted until the bell rang. Then the bell rang at 4:30, I think it was. Then I could see Eckert, and I would go home with Eckert and we would talk at his home about the things that we had to discuss.
Dick:Did they really have a bell that rang?
Strand:They had a bell that rang, yes.
DeVorkin:What kind of a bell? A shipís bell?
Dick:A bell saying that it was time to go home, right? At 4:30?
Strand:Yes, at 4:30.
DeVorkin:Interesting. I need something like that. We donít have a bell. Nobody ever tells us to go home.
Dick:How about Eckert then? You really had no substantive interaction with Hellweg, but how about Eckert? What kinds of things did you discuss with him?
Strand:Well, we discussed various problems that we had in common at that time. For instance, we used his sextant and he was interested in seeing what results we got from using it, and the instructions that went with it.
Dick:When you say ďhis sextantĒ?
Strand:He developed a survival sextant, which he tested.
Dick:What do you mean when you say a survival sextant?
Strand:It was a sextant with a little plastic circular disk with a graduated circle, and there was a sighting device to observe stars, and enabled you to read off the altitude. You could also use it to observe the altitude of the sun.
DeVorkin:How did that differ from previous sextants?
Strand:This was basically a 4 1/2 inch disc that could be made cheaply, and fit in a little plastic cover, with instructions on how to use it, and with some simple tables, so that people if they were Stranded in a life boat, they could actually determine their approximate position.
Dick:And it was developed especially for the war at the Nautical Almanac office at the Naval Observatory?
Strand:It was developed at the Naval Observatory for the purpose of survival navigation, which was very important. We tested it at Eglin Field and gave them the results. We sent people out in life rafts, in the Gulf of Mexico, and tested it, also if they needed water they would have to catch a fish and squeeze the water out of the fish and drink that.
Dick:How were the results of the tests?
Dick:So these things were mass produced then during the war?
Strand:Yes, they were mass produced. And we gave them information about how good they were.
Dick:Did you have interaction with anyone else at the Nautical Almanac Office or the Observatory at that time?
Strand:I saw (Gerald) Clemence occasionally.
DeVorkin:What was your contact with him?
Strand:I knew him already from before. Iíd been visiting there and given a lecture on one occasion.
Dick:He was in the Nautical Almanac Office at that time?
Strand:Yes, he was.
DeVorkin:You became captain, chief navigator, on operational suitability tests of B-29s?
DeVorkin:What was your specific task?
Strand:My task was testing to see how the B-29 would perform under various conditions, similar to the ones that we would possibly have to fly over Japan. So it would vary. We would fly at various altitudes, various loads, and so on. And then check on the fuel consumption, primarily my job was, if there was new equipment on board, to see how it functioned and also to see that we didnít get lost. Because we were flying over the Caribbean, with a lot of open water. You miss a check point and you might be on your way to Europe or South America. There were no navigation aid like Loran.
DeVorkin:You indicated that you trained special air crews. In particular the atomic bomb crew?
Strand:Only the chief pilot.
DeVorkin:Were they referred to as Special Air Crew? Was there a particular term for them?
Strand:No. The one that flew with us, in that particular case, was a Colonel Tibbets, who had been, as long as I knew him, in the Pentagon, and then suddenly he became an operational officer and came down to fly with us, to learn how to pilot and also to hold the various positions such as navigator, bombardier and so on in a B-29.
DeVorkin:Did you know what was going on at that time? That they were planning to drop a nuclear bomb?
DeVorkin:When did you first learn of that?
Strand:I didnít know about it until it actually happened.
DeVorkin:I see. So it wasnít a case of some extraordinarily heavy object in the payload affecting the operational performance of the B-29, you werenít involved in that?
Strand:— oh yes, we flew heavy loads.
DeVorkin:Did you have loads equivalent to what later was the atomic bomb?
Strand:I couldnít say exactly if it was, I am not sure. We flew all kinds of loads. They were all dummies, of course. Some were clusters, some were single bombs, like the tall-boy for instance.
DeVorkin:Thirty thousand pounds was pretty big.
Strand:Yes, it was a big bomb. The only thing was that Colonel Tibbets asked me if I would join his outfit.
Dick:Who asked you?
Strand:Colonel Tibbets. He became the pilot on the Enola Gay. He was going to do some flying over the Pacific. He was going on some special missions and he wondered if I would be available, and I said that the only thing he had to do was to go and talk to my boss, General Gardner. I mean, I couldnít say yes or no to him, and I had to tell him to go and ask the general, so Gardner called me in and told me, no, I couldnít go, I had to stay there, he couldnít spare me.
DeVorkin:You didnít know why or what his was all going to be?
Strand:No. And I donít even know if Gardner knew at that time.
DeVorkin:How did you feel about it when you found out? You didnít know until August of Ď45?
Strand:No, I didnít know.
DeVorkin:And how did you feel about it? Did you find out quickly that it was Tibbets?
Strand:Well, it was published who it was, so I knew he had been involved. It didnít necessarily mean that I would have been flying as a navigator specifically on that particular one, but I might have. I donít know. But the fact that I didnít go — well, I donít know. Once you sit up there, way up in the sky, you feel sort of, a little bit divorced from what is going on down below.
Dick:What special training was involved for the crew? You trained the crew in navigational procedures?
Strand:They had to learn the procedures, how to operate a B-29.
Dick:You mean the navigational crew that went on this special mission had never been on one before?
Strand:Yes, they had.
Dick:So what was special about this mission navigationally?
Strand:This special mission was to have Colonel Tibbet get involved in all the aspects of flying a B-29. So when he got his outfit, he knew what it was all about.
DeVorkin:That sounds reasonable.
Strand:We flew not only single plane missions with him, but we also flew information missions with B-29s.
DeVorkin:Is there anything you feel we should cover about the war years that we have not yet covered? We know from your publication record that papers by you continually came out. Were you able to spend any time preparing and putting papers in to the journals while you were in the service?
Strand:A little bit. Not a great deal. But I learned a lot from the Air Force.
DeVorkin:In what manner? What did you learn?
Strand:Oh, I learned how to be involved with the military as a professional military officer, in the sense that theyíre different. They have a different mentality in many respects.
Dick:I take it that was a valuable experience for later when you came to the Naval Observatory?
Strand:Of course it was. And also how to handle people. That was very important. Not only the other officers, but also the officers I had under me, and how to perform and keep a happy crew. I wasnít just depending upon myself to see that something was successful, but I had to have a whole group. I had something like 25 in the ballistic outfit that had to be kept active and interested in their work. Then also the fact of procurement of equipment — how to deal with contractors. And also to have respect for your equipment to see that it is operational and in good form. In other words, that people will respect the equipment. If the equipment is handled badly, then in most cases it doesnít look good. It should look good, and be available to you in a pleasant form. This is the first thing that happened after I got to the Naval Observatory, that I renovated the 26-inch telescope, because it was a horrible sight.
Dick:Weíll be discussing that much more when we come to that period. Did your war years change your lifelong goals, career goals, general interests?
Strand:Well, I still was interested in the military, and thatís why I stayed in the Reserve. And I was a staff officer, as I mentioned in my papers at the Air University, as a staff member of the Air War College. And I served there during the summers, and that was very interesting in many respects, report writing, participating in war games, using computers.
DeVorkin:Was this your first contact with electronic computers?
DeVorkin:Do you remember the kind you first saw or first used?
Strand:Well, no, I canít offhand say what they were.
DeVorkin:You saw their application to astronomy?
Strand:Yes, I saw that they could produce information in astronomy.
DeVorkin:Maybe we should back up, get you back to Sproul, then Yerkes. Getting back to your publications during this period, you did have some publications during the war years. I take it these were all based on data youíd gotten at Sproul.
Strand:That was data from Sproul that I was asked to write up while I was there.
Dick:These include the papers on 61-Cygni?
Dick:I wanted to ask you, what was the reaction when these papers came out? There were three or four of them in the mid-forties. What was the reaction to your results saying that here were unseen companions, possibly of planetary mass?
Strand:Well, they brought out a lot of discussions, especially by Henry Norris Russell. He was especially interested that we had possibilities of small bodies surrounding other stars. He proclaimed that a mass of 7/100 of a solar mass would no longer be visible.
Dick:Why was Russell so interested in that?
Strand:I donít know why he was. He was interested in practically all aspects of astronomy, more so, I would say, than any other astronomer I know of.
Dick:How about other astronomers? I think in the pages of NATURE in the mid-forties, James Jeans and others had a back and forth exchange because the observational evidence for planetary systems had a bearing on his theoretical idea that planetary systems would be very rare.
Strand:Yes, it did have some bearing on that, because his idea was that they would be extremely rare, and this would indicate that they actually were not so rare, which is what we really think now, that they are not rare.
Dick:I think Jeans did specifically cite your 61-Cygni paper on that.
Strand:Unfortunately it didnít turn out. Iím sure there is a perturbation in 61-Cygni, but we have not accurate enough observations to prove it.
Dick:How are we sure, then?
Strand:Iím sure we have all kinds of stuff around just about any star that we can think of. Just think about Vega, now.
DeVorkin:Yes. Was that very exciting to you, when you first saw it?
Strand:It certainly was exciting. Very exciting. And I think that it bears out what I had felt all along. 61-Cygni didnít have the companion as assumed at that time, which was unfortunate, but we didnít know enough about the optical performance of refractors or how accurate they were. We all thought that they were the ultimate in accuracy that we could achieve in astrometry. Itís been shown since that it is not the case, especially after the results from the astrometric reflector.
Dick:Donít you think that the Vega evidence is actually quite some distance from showing that there is a solar system?
Strand:Well, yes. But it shows that there is matter around it. It might not be a well organized solar system as we look at it. There might be some bigger bodies, some smaller bodies, and so on.
DeVorkin:Letís go back to that earlier period. You had conflicting theories for the origins of the solar system. The Weisacker theory was being presented and distributed, and as you said, Jeans had his.
Strand:Yes, and Kuiper had his. They all had their own ideas.
DeVorkin:What were your own feelings? Because you had been working in binary work for quite some time by that time, had probably been aware of various tidal theories of binary evolution certainly and how they might apply to solar system theories. What did you feel about it?
Strand:How did I feel about how binary stars were formed?
DeVorkin:Binary stars and solar systems. Did you see them as the same mechanism?
Strand:No, I donít see them as the same mechanism.
DeVorkin:At that time?
Strand:No. I donít know either. I donít think anybody does.
DeVorkin:But there was a time when there were statistics — stellar rotation was another indicator — what were your feelings at that time? What theory did you adhere to?
Strand:Well, as I told you before, in many respects, Iím very much like Hertzsprung. I prefer to work with observations and not speculate too much about theories.
DeVorkin:So you disciplined yourself against it, so to speak.
Strand:No, I donít think so. Itís against my nature. I believe in more accurate observations and see what they produce.
Dick:So that you would say that the desire to know whether or not there were other solar systems was not really a guiding principle in your double star work?
Strand:Well, what you could find in one case might be the same in other systems. This is as far as I went. As I said, itís my nature, the same way as it was Hertzsprungís. Hertzsprung started speculating on the evolution of the stars, and after his first paper he gave it up. He quit it. Never got back to it. And never wanted to talk about it again. Any time people came up with some theory about something, then he just dismissed it. Now, I know one person who was very unhappy about this. That was Jan Schilt, at Columbia, because he had the first idea of galactic rotation, and showed it to Hertzsprung. Hertzsprung was not convinced, and dismissed it.
DeVorkin:Thatís amazing. When was that?
Strand:This is what Iíve been told. It must have been between 1922 and 1925, when he was at Leiden.
DeVorkin:That would have been when Kapteyn was still alive, possibly.
Strand:Could have been.
DeVorkin:Now, the first paper you were referring to, thatís Hertzsprungís 1906 paper?
Strand:1905. Thatís the only one in which he says anything about stellar evolution.
DeVorkin:Thatís really very interesting.
Strand:He has never brought it up since.
DeVorkin:Thatís right. Did he ever tell you why? Or he just didnít want to talk about it?
Strand:No, he didnít talk about it.
Strand:He just didnít want to get into theory, and I think in many respects that Iíve followed in his path, because Iíd rather do observations than sit down and speculate. There are a lot of people doing that now.
Dick:So Hertzsprung didnít have any strong feelings or opinions about whether or not there might be other solar systems. Was he involved in that controversy?
DeVorkin:Let me ask one more Hertzsprung question. Itís totally irrelevant to this but it does deal with speculation. Thereís still a question as to who first coined the terms ďgiantsĒ and ďdwarfs,Ē between Hertzsprung and Russell.
Strand:Hertzsprung never did. In fact, he explained why he didnít call them giants. He said that the only way that he could explain that they were giants would be based upon their mass, and he didnít know whether the red giants were very massive or not massive. And he did not believe that the red giants were massive stars.
DeVorkin:He told you this personally or this is in his writing?
Strand:We talked about it, and itís also in an interview that was made when he became 90 years old. He said that he never called them giants.
DeVorkin:Oh! Do you know where that interview is? Has it been transcribed?
Strand:I saw it one time, a clipping in a Danish paper. I promised to give it to W.W. Morgan but I couldnít find it. The only thing he said with respect to giants and dwarfs was about the stars with the narrow lines, the c-stars, which are called giants, ďThere is a comparison here that I can make between the c-stars and other stars. The c-stars are like the whales in the ocean among the fishes.Ē He said that in his early paper. He considered them as the whales in the ocean compared to other stars as the fishes. But he didnít call them giants, only emphasizing they were rarest. And by the way, I should also bring up another thing. One reason he didnít want to lecture was that he never attended lectures himself in astronomy, and he would always say, when he had had some novel approach to a problem, and you talked to him about it, he would say, ďBecause I came into astronomy through the back door.Ē
Dick:In other words, he wasnít biased.
Strand:He wasnít biased by established opinion, by taking courses at a university in astronomy. When he started studying astronomy, he used the scientific publications that were available, and from these derived the results and conclusions in his first two papers. These were really studies that perhaps a professor could have said to a very bright student. ďHere you have all this information what can you make out of it?Ē And he did. He used the observations that had been made at Harvard of the c-stars and the other stars. He went along and checked what their proper motions were, and then realizing, if you want to use proper motions for a statistical study of parallaxes, there youíd better use the fundamental stars because they are the only ones that had reasonable accurate proper motions. And so on. That was the way he developed his distinction between the two classes of stars in his two early papers.
Dick:But what is the difference between learning established theories from books and learning it from lectures?
Strand:He didnít use textbooks either.
DeVorkin:Two questions about that early period come to mind. People often wondered why he published in the ZEITSCHRIFT FUR WISSENSCHAFTLICHE PHOTOGRAPHIE and not in the ASTRONOMISCHE NACHRICHTEN or something like that. Was it partly because he came through the back door?
Strand:He was not a professional astronomer. And the papers might not have been accepted. He was involved in photographic work and was interested in that. He got into astronomy because he was interested in the radiation of the stars, and this is why his papers are entitled, ďFur Strahlung der Sterne.Ē On the radiations of the stars.
DeVorkin:Thatís right. Let me ask about one other person at that period. Thatís Anton Pannekoek, who did publish in the publication of Amsterdam.
DeVorkin:A proper motion study that, when one looks at it, had a lot of the same characteristics as Hertzsprungís early paper.
Strand:Thatís right, but he didnít put it together in the same way —
DeVorkin:He wasnít as complete? He didnít make a statement?
Strand:Yes, thatís it.
DeVorkin:Did you have any contact with Pannekoek?
Strand:I knew him. But he was a pretty old man at that time, and I didnít have much chance to really talk to him. I met him at several meetings but thatís all.
DeVorkin:Did his political activities sort of keep him away from the astronomical community, or did the astronomical community sort of shun him?
Strand:I donít think so.
DeVorkin:But you didnít have a lot of contact with him? Letís move back to where we were. Have we finished your war years in reasonable fashion?
Strand:Yes, I think so.
DeVorkin:OK, then we should move back to Sproul.
Dick:I had one more question about Sproul years, which is, in 1941 you published an article in THE SKY, the predecessor to SKY AND TELESCOPE, on photographing measurements in double stars. I think this was your first venture into sort of popular astronomy. How did that come about, and did you feel then and do you feel now that itís important to write articles such as this, for professional astronomers to do this?
Strand:Well, I thought it was important for professional astronomers to let other people know about what theyíre doing, and so thatís why I did it. I was asked if I would write an article about it so I did.
Dick:You didnít do much popular writing though for the rest of your years?
Strand:No, I havenít. Iíve done very little. My life has been too busy to do other things. Iíve written a few articles for encyclopedias. I just finished one the other day for McGraw Hill, but I donít know whether that would be considered popular writing. It was just to give information.
DeVorkin:Did you ever ask yourself in the last months of the war what youíd be doing after the war? Did you wonder if youíd go back to Sproul or did you really want to do something else?
Strand:Well, there was a big question there. There was a big temptation, because they really wanted me to stay in the Air Corps, but I really didnít feel that this would give me the fulfillment in life that I liked. So I wanted to wait and see what the situation was, and so I went back to Swarthmore, but I was there only a few months, because I went on a Guggenheim Fellowship to Europe. At Christmas time, already, I had an offer of another position.
DeVorkin:That was Christmas of Ď46?
Strand:Ď46, that Struve asked me to come to Yerkes.
DeVorkin:Now, clearly, this was an important question in many peopleís minds, especially people who had prominent and exciting roles during the war. Did you talk with other people? Did you write to Hertzsprung? Did he write back to you? Was there any mutual discussion with other scientists in the military as to what youíd do after the war?
Strand:None whatever, because you couldnít write to anybody.
DeVorkin:Yes, thatís true.
Strand:I couldnít even write to my own mother in Denmark. She didnít even know what had happened to me, since before I got into the Army. She had no idea what had happened all these years to me. The only thing she knew was that I wasnít in Denmark. But the Germans thought I was there. They came once to my motherís home and searched the whole house for me. She told them that Iíd been gone for a long time. Somebody had been using my name, in the underground, I suspect.
DeVorkin:You never found out?
Strand:I never found out and didnít care.
DeVorkin:Did you have any knowledge of V-2 rockets and the possibility of their use after the war, especially in your ballistic work?
Strand:I only worked with the V-is, not the V-2s. I didnít get involved with the V-2s.
DeVorkin:What were conditions like when you got back to Sproul?
Strand:In what respect? What do you mean?
DeVorkin:Well, were you able simply to move right back into research? Start the observing program again?
Strand:First of all, I had to collect all my observations from before the war that I hadnít published.
DeVorkin:You had been publishing?
Strand:Yes, but I hadnít published all the observations I had.
DeVorkin:Had there been anyone observing during the war? To keep your program alive?
DeVorkin:OK, so you put together your pre-war observations?
Strand:The only observations made were of parallaxes. So I put my observations together and got them published in the ASTRONOMICAL JOURNAL. Then I took off for Europe and came back and went to Yerkes Observatory, where they had quite a group of astronomers there.
DeVorkin:So you really did not do too much in the short time you were back at Sproul?
Strand:Oh no, just mostly arrange my observations for publications.
DeVorkin:Could we talk about your Guggenheim Fellowship for a few minutes? What was the purpose of going to Europe on the Guggenheim?
Strand:The purpose of going to Europe was, that there was a fellowship primarily for professional people who had been in the military service, and because of the military service had had no contact with other professionals and what was going on in their field. The idea was that you could go wherever you wanted to go, any institution, talk to the people, see what theyíve been doing and what their plans were and so on.
DeVorkin:Was this specifically Europe or could you have gone to some place in the States?
Strand:I could make my own choice, subject to approval by the Foundation.
DeVorkin:What observatories did you go to?
Strand:First of all I spent some time with the Swedish observatories.
Strand:I went to Lund. I saw Lundmark a great deal. We became very good friends. Lund and Stromgren had been very good friends but they were now enemies. But he and I became very good friends.
Strand:Elis. Bengt Stromgren has no enemies.
Dick:Why had they become enemies?
Strand:I donít know why. It just happened.
DeVorkin:It sounds like the elder Stromgren did not make friends very easily.
Strand:No, he didnít. And I spent some time with Lindblad, and some of the other people at Salbjobaden. I spent some time in Leiden with the group there, Oosterhoff and Oort and some of the other people there.
DeVorkin:Were you there by any chance during the recreation of the seminar where van de Hulst discussed his theory of the 21 centimeter line? I know they recreated it after the war when they were allowed to have seminars publicly again.
Strand:No, I didnít hear him give a seminar.
DeVorkin:Did you meet van de Hulst at that time?
Strand:Oh yes, I knew him.
DeVorkin:Did he seem to be pushed into administration quite early by Oort do you feel?
Strand:I really donít know much about it. Another person that I met for the first time and had a great deal of difficulty in understanding, was Hannes Alfven.
DeVorkin:Hannes Alfven. Understanding in what regard?
Strand:Understanding his theories. I think I was not alone at that time.
DeVorkin:What are you saying?
Strand:His theories of Cosmical Electrodynamics, and magneto hydrodynamic waves. An entirely new field, for which he later got the Nobel Prize. I was also in Paris and talked with Danjon, and so, it was quite a fruitful time.
Dick:The period of time?
Strand:About six months.
DeVorkin:And your purpose was simply to find out what had been going on for your own interest.
Strand:Yes, for my own interest.
DeVorkin:Was there any connection at all to the ALSOS mission of the previous year?
DeVorkin:OK, so you were not interrogating?
Strand:No, I was not interrogating people about anything that was related to war efforts. This was Kuiperís business.
DeVorkin:He was quite prominent in that?
DeVorkin:From your manner of saying that — did you fully approve of what he was doing?
Strand:Yes, but I wasnít interested in getting involved with that phase.
DeVorkin:Did you meet any of the people he interviewed, such as Ravener?
Strand:I spent no time in Germany.
Dick:Did you visit Copenhagen during this trip?
Dick:Was Norlund still there?
Strand:Oh yes, Norlund was still there, and I visited the Geodetic Institute, and I met the other people there. Miss Vinter Hansen was back from the United States. I saw her, by the way, at Lick Observatory, both before and during the war.
DeVorkin:Was your mother still alive?
DeVorkin:And you let her know what youíd been doing these previous years?
DeVorkin:You got the offer from Struve to go to Yerkes as an associate professor in October Ď46?
DeVorkin:Was this completely out of the blue?
Strand:No. The reason was that there was an opening after van Biesbroeck had retired the previous year, and I think that Struve first wanted van de Kamp to come, at least van de Kamp mentioned to me that he had been approached. He turned it down. There was an IAU meeting in Copenhagen afterwards, and Struve told Hertzsprung that he had hired me, and Hertzsprung was very happy about that.
Dick:Had you been recommended to Struve then by van de Kamp after he turned it down, do you know?
Strand:Well, van de Kamp never told me.
DeVorkin:Was this an obvious better position for you?
Strand:Oh heavens, yes.
Strand:Well, first of all, this was a position that would lead to a tenured position, which I did not have at Swarthmore, and also I saw the opportunities there were better. After all, I would be in charge of the astrometric program.
DeVorkin:But there certainly must have been other pressures on the 40-inch, even though McDonald was built?
Strand:No, not a great deal. Most of the staff wanted to use the 82-inch, or use the smaller telescopes. There was a small reflector.
DeVorkin:The 24-inch Ritchey?
Strand:Yes. And the 40-inch wasnít much used. I think there was only one other program, a program with the Bruce Spectrograph, although Van Biesbroeck used it from time to time for visual observations of double stars.
DeVorkin:That was Morganís classification spectrograph, wasnít it?
Strand:No, he had a low dispersion spectrograph, but he was not using it any more at that time, since the observing program was completed.
DeVorkin:Thatís right, he was doing photometric work at that point.
Strand:Well, he was doing spectral classification, he needed.
Dick:What was the size of the Yerkes staff when you came?
Strand:Oh, it was very large. Huge.
Dick:No comparison with Sproul?
Strand:Two later became Nobel Prize winners.
Dick:Which two were those?
Strand:Herzberg and Chandrasekhar. Kuiper was there. Greenstein was still an assistant professor. Others were Morgan, Bidelman, Popper, and Henyey.
DeVorkin:Munch was there as a graduate student?
Strand:Munch was there as a graduate student. He had finished all his work. I think he was in Mexico at that time, and everybody was speculating on when he was going to come back as a postgraduate. And among the graduate students were Art Code, Arne Sletteback, and Donald Oosterbrock.
DeVorkin:That was just before Nancy Roman was there as a graduate student?
Strand:No. Nancy was there, I knew her from Swarthmore. Ann Underhill was also there. We had about 16 graduate students then.
DeVorkin:Let me ask you first about Herzberg. I know that you and he had very little to do with one another, but Struve really went to a lot of trouble to get him there, and a lot of funds were given to him for his spectroscopic stuff.
Strand:Yes. He had his big vacuum tube in the basement of the observatory.
DeVorkin:Was there any kind of animosity toward all of that on the part of the staff?
Strand:Well, I really donít want to go into that, because I didnít take part in it. I never wanted to get into any infighting with anybody.
Dick:Were you particularly close to any of the other staff members?
Strand:Yes, Glenn Hall was my assistant, who came to the Naval Observatory Time Service eventually. He was my chief assistant.
Dick:You probably hired him when you came later to the Naval Observatory?
Strand:No. He was there. I recommended him to Markowitz and he came long before I came. But I had close relations with van Biesbroeck, who was a very friendly man, and also with, Kuiper.
DeVorkin:Kuiper was made associate director.
Strand:He was associate director just before I resigned to go to Northwestern. I went to Northwestern because I felt that I had more of an opportunity there to do what I wanted to do.
DeVorkin:I wanted to ask you that, but first Iíd like to ask you, were there discussions among the staff of Yerkes in the late forties when you were there about how science was to be funded in the postwar period? Whether one should support this new idea of government funding like NSF, go to ONR, which had just been established, continue to seek private funding, private endowment funding like the Research Corporation or the Rockefellers or the Carnegie people? Did Struve have any particular philosophy about that, and did others to your knowledge?
Strand:Most of the time he was absent. He spent most of his time in Texas. Oh, by the way, Al Hiltner was also there at that time. He was an assistant director and also an assistant professor. And Morgan and I were the only two associate professors there. We didnít have very much communication with each other, Struve and I. The only thing I can recall, when I got there was, that when I said I needed some money for instrumentation, Struve said, ďWell, go out and see where you can find some, but I donít have any.Ē
DeVorkin:Was that basically the way it was?
Strand:Yes, that was basically the way it was, and — suggested one source and he said, no, I couldnít do that, because Hiltner had an application there and he had been longer at the observatory than I had, so he was first, and his application had to be accepted or rejected before I could apply.
DeVorkin:You did get money from the Research Corporation to build your objective gratings for the 40-inch?
Strand:No. I didnít get that from the Research Corporation. I got that from the Gould Fund. The Research Corporation didnít enter in until after I got to Dearborn. Dearborn Observatory was the one that got the money from them.
DeVorkin:Those were gratings for the 40-inch?
Strand:The Gould Fund I used for the 40-inch for gratings. I just had to buy the materials because we had the instruments makers and shop facilities.
Dick:What was the funding mix at Yerkes then? The salaries were paid by the University of Chicago?
Strand:The University of Chicago. We were faculty members in the astronomy department of the University of Chicago. Walter Bartky at that time was either dean or chairman of the astronomy department.
Dick:Bartky. His son is here in Washington now. Thorton Page was there too, I think.
Strand:No, Page was on the campus. We had little relations with the campus.
Dick:As far as research funding goes you were pretty much on your own?
Strand:We were on our own, yes. You could bring your tin cup anywhere you wanted to.
DeVorkin:Well, it doesnít sound like anywhere.
Strand:— as long as you didnít bring it to the same place as somebody else.
DeVorkin:You also built a double star camera when you were there, with Art Code?
Strand:Yes. But that was later. That was when I was already at Dearborn.
DeVorkin:I see. So obviously things got very complex when you were at Dearborn, because you were still building instrumentation for the Yerkes Observatory and working there. You still had a staff position there?
Strand:I had a staff position as a research associate with the rank of professor.
DeVorkin:And you were director at Dearborn?
Strand:I was director at Dearborn and I also taught a course for two years at Yerkes.
DeVorkin:Now, your lack of opportunity while you were full time staff at Yerkes — what did that say about the role of astrometry among the staff? Did they not support it to the degree that you wanted it to be supported?
Strand:Well, they all had their own interests, every one of them. And they really didnít care much about anybody else, and really had little time for it.
DeVorkin:No matter what it was?
Strand:No matter what it was, thatís right. Everybody worked on his own. Chandra worked on his. Kuiper worked on his, and so on.
DeVorkin:Did you take any interest in Greensteinís experiments with the V-2? Not personally of course, but were you aware what he was doing?
Strand:Yes. I knew what he was doing.
DeVorkin:Iíd be interested in your recollection of what other people thought of that kind of work at that time. What did you think of what he was trying to do?
Strand:Well, I thought it was interesting. I thought it was very good. In the same way I was also very much interested in what Kuiper did with his infrared work.
DeVorkin:Did Kuiper want to fly anything on a rocket at that time?
Strand:I donít think so, because if he wanted to, he could have.
DeVorkin:How did people feel after Greensteinís experiment failed?
Strand:I donít know. I didnít talk to anybody about it.
Dick:It sounds as if there was not much communication among the staff. Were there seminars held, for exchange of information, even though people were pretty much working on their own?
Strand:Yes. Every one gave lectures that not everybody else understood. We also got involved once in big discussions about this, and Chandra telling Struve that Struve could see things that nobody else could see in a spectrum, and then Struve say, ďWell, you stand up there and write formulas from the top left corner of the blackboard to the bottom right, and nobody understands what itís all about.Ē They were all specializing, you see, some in very esoteric fields. None of them were down to earth like astrometry, that everybody can understand.
DeVorkin:Did you have responsibility for maintaining the 40-inch? Upgrading it?
Strand:Well, if the money had been available I would have. But I left before the National Science Foundation, and also before ONR really got involved in funding.
Dick:When you say you left, you mean that you no longer had a full time position but you were still there as a research associate?
Dick:Which involved how much time?
Strand:As much time as I wanted to give, usually a day a week.
DeVorkin:That was when you were at Northwestern?
Strand:At Northwestern I had an agreement that I could spend as much time as I wanted at Yerkes.
DeVorkin:But it sounds like you were awfully busy, you were at Yerkes maintaining a double star mass ratio program and doing parallaxes. At Northwestern you upgraded the telescope?
Strand:Yes. We did double star work.
DeVorkin:Double star work. There was teaching. There was administration. And it was there that you got the Research Corporation money?
DeVorkin:Now, did you apply for it personally as a member of the faculty, or did you go through some kind of a grant office at Northwestern?
Strand:There was no grant office. I knew the representative of the Research Corporation. He came to see me, because Grote Reber had applied to the Research Corporation for money and so Research Corporation asked one of their representatives who had a Chicago office, from where he traveled to various universities and interviewed people about their work and if they needed money for it, primarily in chemistry. And so this person came to Northwestern University and asked me what I thought of Grote Reber, and his ideas about radio astronomy. And I told him that I thought it was very interesting, and probably something that was going to be very important in the future. And so he said, ďWell, if you had anything to do with it would you support it?Ē And I said, ďI certainly would.Ē And they supported him, and I think theyíre still supporting him.
Dick:Do you know what other people were consulted in this decision? Were other people consulted?
Strand:Grote Reber went to Yerkes, I believe it was before the war, and gave a seminar, and none showed real interest in supporting it.
Dick:They were not interested in radio astronomy?
Strand:They did not seem interested in his work. This was an entirely new field, and they were not sure what it was all about. So, in the process, this same person asked me if I was in need of any money.
Dick:Grote Reber was for ten years alone in the field?
Strand:Yes, he was all by himself.
Strand:And paid for everything out of his own pocket.
Dick:Was he funded in subsequent years by the Research Corporation?
Strand:Yes, he was funded by the Research Corporation.
Dick:But he still paid some out of his own pocket?
Strand:Yes, I believe so.
DeVorkin:You remained at Northwestern throughout most of the fifties?
Strand:I was there for 11 years.
Strand:I started out right away as a tenured full professor, as the chairman of the department, and as director of the Dearborn Observatory. I turned it down first and then accepted.
Dick:Why did you turn it down first? They why did you accept it?
Strand:Well, I was afraid it was going to be too much teaching, as I told the dean at the interview. He had a luncheon for me and afterwards I came back to his office and chatted with him, and he said, ďIt would be a great idea if you could set up a course which would combine astronomy, geology and geography, and call it Heavens and Earth.Ē And I said, ďIt sounds like Hell to me.Ē He laughed. He had a good sense of humor.
DeVorkin:Was that before you accepted or after you accepted?
Strand:That was before I accepted. And I left, I went back to Yerkes and picked up my stuff and went to Sproul, where I was going to observe, and when I was at Swarthmore he called me long distance, and he upped the ante on the salary — the dean did. So when I came back I talked it over with a friend of mine that I knew from my Swarthmore days, who was now professor at Northwestern in political science, as to what I should do, and he said, ďAccept it.Ē He said, ďTell the Dean that you want to continue the work at Yerkes at the same time.Ē
Dick:What was his name, the professor?
Strand:His name was Roland Posey.
DeVorkin:Roland Posey was the one who was influential in getting you to accept the position?
DeVorkin:He was a friend?
DeVorkin:Well, how did you find it, were your fears born out, about administration, teaching and other things?
Strand:Well, it became a very busy life, I can tell you. But fortunately I did not have to teach a great deal, so in that respect, it made it easy on me, but then also I had other duties at the university, with administration and so on.
Dick:How large was the astronomy department at Northwestern at that time?
Strand:Well, when I got there I had to hire a secretary, and the only other staff member was an assistant professor, Wasley Krogdahl.
DeVorkin:Yes. Those were the only two?
Strand:Yes. Then I got an assistant right away, who had applied for a position at Yerkes, and took a job with me, and stayed most of the time I was at Northwestern. Then as we got the money from the Research Corporation, we built new equipment, and had additional funds for assistants, and built up a small staff. Nothing big. But we were only two teaching, except for short periods when I had an additional person.
DeVorkin:At the time you went to Dearborn, the original mounting was still in place on the 18 1/2 inch — is that correct?
Strand:No, it was replaced in 1910-11.
DeVorkin:It had been removed already?
DeVorkin:Who was responsible for that?
Strand:This was done when Dr. Fox was director (Philip Fox). It had a wooden tube.
DeVorkin:That telescope is beautifully preserved at the Adler Planetarium.
Strand:Yes, it is.
DeVorkin:I just wanted to know who we had to thank. Wasnít Philip Fox also at the Adler?
Strand:He left Northwestern in 1930 to be director of Adler, and left to head the Museum of Science and Industry when that was founded in 1937.
DeVorkin:So thatís early thirties?
DeVorkin:So who was at Northwestern between that time and when you came?
Strand:Oliver Justen Lee, who had been at Yerkes, and who was interested in red stars.
DeVorkin:What was the relationship between Northwestern and Yerkes? Looks like traditionally there had been a lot of contact.
Strand:Yes. That continued, of course.
DeVorkin:Did you find that you really were able to get more science done in this way?
DeVorkin:You had more leverage at Yerkes?
Strand:Yes, more at Yerkes, and if we needed some to pay for something, like for instance, an automatic guider, I had the money from Dearborn, I could spend on developing equipment there.
DeVorkin:And no one at Northwestern looked at this kind of funny?
Strand:No, after all, we got the money for my research, and whether we did it at Yerkes or at Northwestern, it was the same. And usually we developed the equipment at Yerkes, because of its instrument shop, although I used also the physics shop at Northwestern, to build equipment. That shop built several of the automatic cameras, of which one went to South Africa for Dr. Brouwer.
Dick:What was the origin of that double star camera? Who designed it?
Strand:Well, it was sort of a joint effort between Art Code and myself, and it was really very simple, but very effective.
Dick:What were the specific new design features in this camera?
Strand:Well, the design feature is that you can take 30 exposures in a row automatically, which we used for double stars observations. You could set the timing, and then it would shift between exposures, and have a shutter that closes when moving to the next position. Thatís all.
Dick:What is the time scale weíre talking about here, seconds or minutes?
Strand:All the exposures were in seconds.
Dick:Between the exposures, what was the time?
Strand:Oh, a couple of seconds.
DeVorkin:Was there automatic guiding during the exposures?
Strand:There was, later on, yes. Initially there was not, because the exposures were fairly short, and we had no guider.
DeVorkin:Where would the original automatic guider be at this time? Do you know? Say we were interested in it at the Smithsonian possibly.
Strand:I think it was scrapped a long time ago. What happens to these instruments is that parts are taken to be used for something else.
Dick:That always happened at the Naval Observatory.
Strand:And astronomers are funny in that respect, they love to take things apart, but normally, they donít know how to put them back together again. Like taking watches apart. Thatís why Walter Baade said one time to me: ďIf you built that telescope, donít let anybody with a screwdriver come near it.Ē
Dick:Referring to the 61-inch?
Strand:Yes, when I first proposed it.
DeVorkin:How about the double star camera itself? Are any of those still around, the originals?
Strand:Not the original ones. One we brought back from Washington to Northwestern, where Hynekís staff took it apart, and since then we made other cameras at the Naval Observatory that were more simplified.
DeVorkin:There was a double star camera as I recall at Lick. Was that from your first design?
Strand:That I donít know.
DeVorkin:It did the same things as you had discussed just now?
Strand:Well, it could have been.
DeVorkin:There was even one not used for double stars but used for a flare star patrol at Griffith Observatory in Los Angeles.
Strand:It could be that it was built later on by Weithbrecht, you remember Weithbrecht?
DeVorkin:Yes, at Stanford Research Institute.
Strand:He was an assistant at Yerkes and built the first guidance system we had, and he saw the multiple exposure camera there.
DeVorkin:He was very late fifties? Early sixties certainly.
Strand:Early sixties. He was a deaf mute, you know.
DeVorkin:Interesting story. During the fifties, in addition to building and maintaining these programs, you began to work more toward establishing what Iíd call the state of astrometry, through having conferences to draft resolutions for the planning of catalogues or new instrumentation.
DeVorkin:You said that in 1953 you had a request from Clemence and Brouwer to chair an astrometry conference at Northwestern?
DeVorkin:This is the first of the conferences?
Strand:This is the first International NSF Conference. Yes, the first we had. And we had some very prominent people there, Danjon, Heckman, Stoy, Spence Jones. All told about 30 well know astronomers attended.
DeVorkin:These are all familiar names?
Strand:Yes. And on the basis of that the AGK3R was planned.
DeVorkin:You also mentioned that the Brouwer double astrograph was planned at that time too?
Strand:Yes. That came about that time too.
DeVorkin:This was to complement the Lick instrument?
Strand:To complement the Lick instrument, yes. But that came a little later. I think I was involved with it after I came to the Naval Observatory.
DeVorkin:Just to close off at this point, were people getting concerned with the need for greater accuracy in astrometry?
DeVorkin:What were the major problems perceived to advance the state of the art of astrometry at the time?
Strand:Well, first of all was to get modem observatories, get support for these observations, and make a coordinated program that would make it feasible to do this on a big scale. I think we accomplished that.
DeVorkin:Was there also a question of exciting younger students into the field? How did you plan to do that?
Strand:Unfortunately there were very few at that time. Very few. And this was one of our problems. I think I mentioned in my paper at that time that we did not have any young people entering into the field of double star observations, for example.
Dick:Because they were more interested in other areas?
Strand:Yes, more interested in other areas and also universities too wanted to have people who could create a publicity and make new discoveries like we are now doing almost every day with the Space satellites.
OK, Iím at the end of the tape, and we hope to have another session with you soon. Weíll pick up with the state of astrometry, would that be OK? I think we should discuss that in detail. Thank you very much.
Session I | Session II