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Oral History Transcript — Dr. Helmut Abt

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Interview with Dr. Helmut Abt
By Patrick McCray
In Tucson, Arizona
October 28, 1999

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Helmut Abt; October 28, 1999

ABSTRACT: Abt discusses his childhood and youth in Germany and then the United States; his student days at Northwestern University and his graduate work at Caltech; use of the Mt. Wilson 100-inch telescope; research topics include W Virginis stars and Zeta Auriga; his work at Lick Observatory and later at Yerkes; use of the McDonald 82-inch telescope for postdoc research; site survey for the building of Kitt Peak in 1959; life at Kitt Peak in its early years including building and design of new instruments; his work as editor of The Astrophysical Journal and the changes that took place over the years; and the final part discusses his personal life and public service efforts.

Transcript

McCray:

I received the CV that you sent to me, and I figured we would spend the first part talking about your early years, and then of go in a chronological order.

Abt:

How far back do you want to start?

McCray:

Let's start with Germany, 1925.

Abt:

Okay. Well, my father had a furniture factory in Germany, which he lost during the inflation in Germany, which was the early '20s when salaries went from hundreds of dollars to thousands to millions to billions, and so on. And so the family got discouraged and they decided to immigrate to America, which they did in 1927. I was born in 1925 so I was two years old when we came over. I don't remember anything about it.

McCray:

The town that you were born in, Helmstedt?

Abt:

Helmstedt. It was the town on the border between East and West Germany at the time and it was on the main road to Berlin. And so when the Russians were stopping trucks going across to East Germany, that's where they did it. Anyway, I'm very grateful to my parents for moving over here because I wouldn't have liked to face Nazi Germany and things that happened after that.

McCray:

Right. So their reasons for coming over were primarily economic because of the de-valuation of the deutsche mark.

Abt:

Yes, they lost most of what they had and it was a bleak time. They had relatives and relatives here who sponsored them.

McCray:

Where did your family settle then?

Abt:

We moved around several times. First to Grand Rapids. My father then became a furniture designer. And the centers for furniture at that time were Grand Rapids, Michigan; Jamestown, New York which is in western New York on Lake Chautauqua south of Buffalo, and some in Cincinnati. And later on of course a lot of this moved to the south, but these are cities where they had a large number of skilled European craftsman. Jamestown for instance had a lot of Swedes, and they had been brought up to do excellent woodworking.

McCray:

Was furniture something that had been in the family before your father?

Abt:

No. He got basically a Masters Degree in furniture design and was able, of course, to make his own furniture. You should see the clock he made, which is all kinds of inlaid woods, curved glass around, mother of pearl inserts, and all kinds of things like that. Which was his master's thesis basically. He had a rough time. He didn't really get used to America very well. He only spoke English somewhat brokenly. My mother tried harder, and she helped him along. Then he died very abruptly in 1940. We moved from Grand Rapids to Cincinnati, Ohio, then back to Grand Rapids, and then to Jamestown, New York in 1931 when I was six years; we lived there until 1940. But that's then during the Depression in this country. And one of the first things that people stop buying during the Depression is furniture so that hit the furniture business badly. My father was sort of brought up in the German school, which followed the Bauhaus tradition and emphasized modern furniture. When he came here he found out that people wanted maple and colonial furniture and some French period furniture, and things like that.

McCray:

More ornate type pieces.

Abt:

Yes. So he tried to push for modern furniture, but it was a rough struggle to do that.

McCray:

What was your mother's background?

Abt:

She came from a moderately wealthy family. She had gone to the equivalent of college and had nine years of English, seven years of French, and so on and so forth. Plus other things, she played piano very well so it was a very much of a liberal arts education. Then she married at the age of 20. So she helped my father along during those years until 1940 when he died very abruptly of a heart attack. And then she for the first time in her life had to go out and work, because she had two sons aged 15 and 17...

McCray:

Were you the oldest?

Abt:

No, I was the youngest. ...to support, and a meager insurance. And so she went to a secretarial school and learned to be a stenographer and an accountant. And she had various jobs after that mostly in accounting for insurance companies and other kinds of companies, until she retired.

McCray:

Where did you grow up mostly? You've named Grand Rapids and Jamestown and Cincinnati, but was one of them more home than the others?

Abt:

The first ones I hardly remember. Jamestown at age 6 to age 15 is the one I remember vividly. Then in 1940, my father took a job in Chicago working for, of all things, a company that makes baby furniture called Shower Brothers. He was very versatile. He designed radios, he designed silverware, furniture of all kinds and so on. So he'd had instinct and training and was very skilled so he could do all these things. So we moved to Chicago, and it was later that year that he died. But when they moved to Chicago, they made a sacrifice for the boys, my brother and I, in a sense that they found out where the best high schools are, and found out Oak Park- River Forest Township High School was one of the best in the region and so my father accepted a long commute to south Chicago just so that the boys could go to a good school.

McCray:

So both you and your brother went to high school there.

Abt:

Yes. At that time there were three outstanding high schools in the area: Oak Park, Evanston, and New Trier. New Trier is north of Evanston.

McCray:

What do you recall of high school? What subjects were you interested in?

Abt:

Science, mathematics. Mathematics was easy. I tried various things, everything from chorus on to history and so on. Oak Park High School at that time was a tough high school. When I went from there to Northwestern, I found Northwestern easy—a snap. So these things happen.

McCray:

Was your brother also interested in the sciences?

Abt:

Yes, he majored in chemistry in college until after he came back from the War, and then he went into economics and went into business.

McCray:

So when you were growing up and when you were in high school, did you know that you would go to college or was that uncertain?

Abt:

I always more or less assumed that.

McCray:

And when you were in high school, when did you first become interested in science? I mean, did you know from a very early age that you wanted to do something with math or physics?

Abt:

Well, math was easy. Science— Well, I think most intelligent young teenagers are attracted to astronomy just because it's something they can visualize and are taken by the observational perspective. But that fades with time. And what almost all astronomers do later on is they go to astronomy by way of physics. That is they learn a lot of physics and then they realize that this can be applied to astronomical objects and that seems to be much more mysterious and more fun than physics laboratories.

McCray:

You seem to have done that. Your bachelor's degree was in math and then your Masters was in physics and then you Ph.D. was in astronomy.

Abt:

Yes.

McCray:

Did your parents have any reaction to wanting to be a scientist? Was there any desire that you could take a more practical career and become an engineer or a lawyer or something like that?

Abt:

No, fortunately they didn't push us; they didn't pressure us to do anything. They assumed that we would do well. It was just sort of assumed. And so we did well, and we worked hard.

McCray:

Where there books or popular treatments of science or astronomy that you remember from that age? I remember reading a biography about Thomas Edison when I was about 10 or 11 years old and thought it was the best thing in the world. Was there anything equivalent to that for you?

Abt:

Not the same thing. I read some astronomy books and then when I went to— Do you want to go to college now or did we finish with high school?

McCray:

You can go college if you want.

Abt:

Okay. I went to Northwestern primarily because they were nearby. My mother was working in Chicago then and so she could commute from Evanston as well as she could from Oak Park, so we moved up to Evanston. By that time my brother had gone off to the military, it was during the War, and I went to Northwestern. Of course I took an astronomy course and found it boring because the professor, Oliver Lee, had promised the students that he would use no trigonometry. And that happens these days too, you know. Even ratios throw some students. So it was all easy so finally after a while I said, "Professor Lee, could I sort of pass the rest of this stuff by examination and go on from there?" And he said, "Yes." So I finished reading the book and took a couple of exams and passed the next two quarters by examination. That, however, was during the War and they had only a few teachers and they really weren't prepared for advanced courses. But they had a huge project involving tens of thousands of stars. They were looking for late type dwarfs. Of course most of the late type stars you find on a objective prism plates are giants and find very few dwarfs. And so they had this big project looking for more dwarfs, and frankly didn't find very many. That's sort of expected. They needed somebody to measure magnitudes of these stars on photographic plates, so I came along and they put me behind the photometer and I spent hours and hours and hours measuring little specks on photographic plates. That was boring too. So I thought, "Well, if this is what astronomy is like, I think I'll look into something else." About that time I became involved in physics. But while I was in physics and getting a master's degree, three of us in physics— oh, a couple of new people came to Dearborn Observatory and Astronomy Department.

McCray:

This is where you were doing the photometry and looking for the late dwarfs.

Abt:

Yes, this is under Oliver Lee. But he was replaced by Kaj Strand. He soon after that became director of the Naval Observatory until his retirement. He also brought in a new Ph.D. from Yerkes who worked under Chandrasekhar by the name of Wasley Krogdahl. So three of us in physics approached Wasley Krogdahl and said, "How about giving us a course in Astrophysics?" And he said okay. There were no restrictions at that time. Three was enough to get a course. We used Goldberg and Aller and I thought it was wonderful. You can do all kinds of things with physics and learn things about stars which you only see as pin points of light, but you can interpret that and learn a lot about the physics coming out.

McCray:

So that was a lot different than measuring the magnitudes of stars on photographic plates.

Abt:

Yes. So astrophysics is more prominent than astronomy. So then I decided I would go in astronomy and astrophysics.

McCray:

You finished your master's at this point? I guess you were finishing it.

Abt:

I was finishing it then, yes. I did it in spectroscopy under Russell Fisher. He was a colleague of Sam Goudsmit. During the late part of the War and after, Goudsmit headed a project called ALSOS (it's a Greek word; I forgot what it means). They were wondering whether the Germans were making any headway on a nuclear bomb, an atomic bomb, and they had no information about this. About that time, the late part of the War, there was a bridgehead that went up into Holland and just barely crossed the head waters of the Rhine River. They reasoned that if there was any kind of work on atomic energy or atomic bomb in Western Germany, the radioactivity would get into the water and go down the Rhine. So under fire, Russell Fisher crawled across the bridge at Remanajin and lowered three bottles of water down into the Rhine, retrieved them, and then went back.

They didn't have any equipment to measure radioactivity there, so they sent them by plane to Washington. They had three bottles and it didn't package very well, so they grabbed a bottle of French wine and stuffed it in there with a note on it, "Check this for radioactivity." Well, the message came back said, "The Rhine water had no radioactivity." That meant that there was no big effort in Western Germany in the direction of atomic energy or atomic power. That turned out to be true. But they said, "Radioactivity in the French wine; send some more." So they sort of laughed that one off. It was the guys in Washington wanting some more French wine. But then they got more and more orders for more information about this French wine.

It does happen that sometimes things like wine do have radioactivity in it from the soil, from the grapes, from who knows what. So finally Goudsmit sent Russell Fisher to Southern France where the wine came from and got samples of wines, samples of the soil, samples of the water and sent it all off to Washington and that settled that. Goudsmit was at Northwestern for a while, the new head of the Physics Department, which was a step upward. And then from there he was Chief Editor of the Physical Review until his retirement. Russell Fisher taught at Northwestern in Laboratory Spectroscopy. And I did a master's thesis on hallow cathode discharge tubes to see whether they could produce reasonable abundances.

McCray:

Did you have any picture in your mind of what you wanted your career to be at this point?

Abt:

No. Well, if you go into astronomy you want to be an astronomer.

McCray:

But were you drawn to make new observations or the theory aspect of it?

Abt:

Yes, I wanted to be an observer in probably the area of spectroscopy. So that part was fairly clear. I applied at two places. I applied at Princeton and was accepted. I applied at the University of Chicago, whose Astronomy Department was the Yerkes Observatory. All the astronomers were at Yerkes then. I went up there and talked to people like Chandrasekhar, Gerard Kuiper, Al Hiltner, Morgan. This was one of the high points in the history of Yerkes, and I met a lot of the students; that was just after the War, and they were marvelous students: Ann Underhill, Nancy Roman, Bob Hardie, Arne Slettebak.

McCray:

Pretty big names.

Abt:

Yes. But they didn't have an assistantship to offer me. But then I heard that there was going to be a new department starting in the fall of 1948 at Caltech. In June of that year they had dedicated the 200 inch telescope. And Jesse Greenstein, who was at Yerkes, was going to head a new department. This was planned for sometime and after the 200 inch was finished, they had a formal department of astronomy at Caltech, and Jesse Greenstein was head of it. Fritz Zwicky (a very colorful person) was there, Albert Wilson, and others. These are the main people who taught.

McCray:

Did you have classes with Zwicky?

Abt:

No, I avoided him. He was a demanding teacher; he was very eccentric. He taught a course in mechanics. There are interesting stories about Zwicky. He was rather pompous and gave a tough course. Some people of physics decided they would play a trick on him, so they enrolled an imaginary student in his class and the imaginary student never showed up to class. So at the final examination Zwicky says, "Now I'm going to see the student who can sign up for my course and has turned in beautiful homework papers, but I've never seen him." Well, at Caltech they have an honor system in which people don't cheat, hardly cheat, and people are on their own honor. So during an examination you can walk in and out of the room, you can go off to the men's room and so on. So it was easy to slip things in and out of the room. In an adjacent room, a nearby room, there was several faculty and post-docs working on Zwicky's examination. And of course they got all of the problems right, but the handwriting got worse and worse as the examination paper went along. And finally, at the end, a scroll, which says, "I'm too drunk to go on."

McCray:

I just remember (I can't recall where I read it), but it's a reference to a lot of his colleagues that says, "Spherical bastards, because no matter which way you'd look at them, they were still bastards." That just struck me as a really funny comment.

Abt:

That's very outspoken, typical of Zwicky. He was a brilliant person and his thinking was far ahead. A little bit too cock-sure though, and, I think, egotistical. He had a set of books that was on the shelf I noticed once that said, "The Collected works of Fritz Zwicky." So Zwicky never found out who the student was. Anyway, because they were short faculty members, they brought in people for one quarter at a time to teach the four or five students who were there.

McCray:

Who else was there besides yourself?

Abt:

The first year started with Allan Sandage, Morton Roberts, a fellow by the name of Jim Parker who dropped out, and myself—four students. Mort found it rough going and accepted a Master's degree after the first year. He went to teach at Pomona College and then later on he enrolled in Berkeley and got a Ph.D. Sandage and I were very determined; it was a discouraging time. He came from the University of Illinois where his father was a professor.

I came from Northwestern, which is relatively an easy school. And we weren't prepared for the Caltech courses. I'll give you one example. We were taking a course in optics. And most of the courses were problem courses, consisting of reading a book and doing the problems. Next Monday we'll talk about them. So the professor, Robert King who was teaching optics, assigned five problems. Sandage and I each worked on them separately and we didn't get anywhere on any of them.

Finally we talked to each other and said, "Have you got these?" "No, I haven't gotten anywhere on these." So we worked together and we got no where on any of them all week long. Finally we came to class on Monday thoroughly demoralized. And then Professor King says, "Mr. Ferri, do you have the first problem?" So he went up to the board and in two lines he had the answer. It was obvious once you saw it. "Mr. Parker, do you have the second problem?" "Yes." Two lines and there was the answer. We felt about three millimeters high. We learned later on that Ferrill was the most brilliant student they ever had at Caltech. He went through as an undergraduate and got all A's. Parker was Eugene Parker. And the rest of the class were like us—just barely getting out.

We decided we would stick it out. Other people in successive years came and left. It was just too rough. You spent all your time working. Maybe once a month we'd go to a movie, and then felt guilty that we'd wasted our time. But Sandage and I both decided we would not leave. We would stick it out until they flunked us. And they never did. So we got Ph.Ds.

McCray:

Do you think that was the secret? Just to persevere?

Abt:

Well, that's one of the things that you need for astronomy, right? It is a difficult field. Most research is hard because you have so few clues and so little information. You have to know a broad range of things. If you're an observer, you have to put up with observing long cold winter nights. Sometimes you get involved in long, tedious observations or reductions, which now days are much easier with computers. But in the days of the Marchant, try doing a stellar interior model with a Marchant, or Monroe. Before I used to do least square solutions for spectroscopic binaries. It's a method developed by Bessell, I think. It's long, and if you make no mistakes, about eight hours to go through one solution. Now of course computers will do ten of these in three seconds. But that was long and tedious and you have to have a lot of determination in order to do it. If you gave up easily, hey, you didn't have the makings of an astronomer. So I think people were clever enough to realize this.

McCray:

You said that you would have guest lectures come in and that there were only four or five faculty. Who were some of the other guest faculty who came?

Abt:

Jan Oort, Bengt Strongren, Cowling. Little names! There would be a class of four or five people and they have Cowling giving a course to this small group. It was a marvelous opportunity.

McCray:

Did you have a favorite professor at that point? Or a particular subject that you really liked?

Abt:

Well, I liked spectroscopy, got a Ph.D. thesis under Greenstein. I was his first student.

McCray:

What was he like to work with?

Abt:

Greenstein related in a different way. He'd think quickly. I'd never seen a person who if you presented him a problem he throws around the factors of 10 and so on and comes up with a rough answer. As a lecturer, he was not so good because he wasn't organized enough. When he got off a subject in his notes and talked about things he knew, he was wonderful.

McCray:

How did you become his student?

Abt:

At that time it was the Mount Wilson and Palomar Observatory. It was a cooperative arrangement between Carnegie Institution of Washington that owned Mount Wilson and Caltech that owned Palomar.

McCray:

So you have a cooperative arrangement between...

Abt:

Between the two, so that people on the Mount Wilson staff could teach at Caltech and some of them did. Also, a lot of us worked at Mount Wilson. Allan Sandage used to work for Hubble, and he became Hubble's student for the four years he was there, and then of course did a thesis under Hubble. I worked for Olin Wilson who is a spectroscopist. The project that we worked on is zeta auriga. Zeta auriga is a remarkable system because it consists of a very large K supergiant and a B star which revolved around it in a period of two and two-thirds years. The B star is very small compared to the supergiant, and it's an eclipsing system, even with its long periods. So once every two and two-thirds years the B star moves behind the K star. While it's going behind the K star's

Abt:

atmosphere until it finally disappears completely. That takes 10 days to two weeks, so that every night you can sample a different part of the atmosphere by using the B star essentially as a continuum and then seeing what absorption lines are added to that spectrum from the atmosphere of the K star.

McCray:

Sort of using that as a filter almost.

Abt:

Yes. Well, like a search light passing behind it. And then you can see the amount of material along these lines of sight and you can determine then the characteristics of the atmosphere of the supergiant as a function of height above the star. You can determine the run of density and temperature and electronic pressure and so on. So Olin Wilson had received several weeks of observing time with a hundred-inch to get this material, and I spent most of the four years analyzing this. We learned a lot about the atmospheres of supergiants from this kind of information.

McCray:

Did this become your dissertation topic at all?

Abt:

No. That was paid work. I worked 20 hours a week and I got paid $100 a month.

McCray:

25 a week.

Abt:

Of which $11 a month went for income taxes and I tried living on the rest. Well, I was fortunate because I didn't think this was enough. I didn't have much money saved up. So I asked at the Caltech employment office about places to live, and it turns out there was a doctor's family in Pasadena who were looking for somebody to live in a spare room they had, basically a maid's room, and to be available as a babysitter anytime they wanted. Well, this turned out great. I got a free room, about half my meals there, and two or three nights a week or three or four nights a week they went out and I took care of their two boys. I was happy and they were happy, and we've been friends every since. So that's what made it possible to live on S89 a month. Sandage had been in the military in the Navy and he had some GI Bill money, and that helped him.

McCray:

So what facilities were you using at this time? You said you were doing the spectroscopic work with the red super giant and then the B star.

Abt:

Yes, microphotometer. After that it's all hand work on tracings.

McCray:

How did Greenstein then become your advisor?

Abt:

Of course after two and a half years of course and you start looking for thesis topics and they suggested a couple of things. And one of which I accepted readily was a discovery by Sanford that there's a kind of Cepheid called W Virginis. There are two kinds of Cepheids. The population I Cepheids are called Cepheids, and the population II Cepheids, which are found in globular clusters, are called W Virginis stars. Later on this distinction became very important because people were determining distances to objects like globular clusters and thinking that they're looking at classes of Cepheids, but they weren't; they were looking at W Virginis stars. And the luminosity to a given period is different by magnitude by a factor two.

McCray:

So in the classical Cepheids, the brighter it is, the longer it's period is.

Abt:

Yes, that's true for both kinds. So they both have a period - luminosity relationship, but they're displaced by a factor of two. And so you have to be sure that if you want to use these stars for distance determinations, you know which kind of Cepheid you're looking at. This became important later on in the distance scale of the universe because they're using one kind in one case and another kind in another case, and they made it an error by a factor of two.

McCray:

So if you were going to use the Cepheids as reference markers you had to know which kind you were looking at in order to know how the steps in the ladder turned out.

Abt:

That's right. And in fact that's still the basic method for determining distances out to some of the near clusters of galaxies.

McCray:

So this then became your dissertation topic, working on this particular type of Cepheid?

Abt:

Yes. But it wasn't for that reason. Sanford had found out that the spectra of these W Virginis stars at times had double absorption lines, and this is something that needed to be explained. So I got spectra with 100-inch of W Virginis, which is difficult because it's about 10th magnitude star and are basically all night in exposures. But in the course of a couple of weeks of observing time, not all in one cycle but spread out over a number of months, but I had a set of spectra. I should tell you one more thing about these. Classical Cepheids come from V stars, and they have masses around 10 or 15 solar masses. W Virginis stars come from solar type stars which became giants, and then they move off the giant branch and so they have masses around one solar mass.

McCray:

So they would be older though?

Abt:

Yes they're older, but also there's a big difference in mass. And that accounts for the fact that they're pulsating different modes. But here you have a case in which it has a relatively small mass and a very, very tenuous atmosphere. They're supergiants. And since they have a small central mass, the surface gravity is low. It is a pulsating star that is expanding and contracting, expanding and contracting. When it contracts it gets hot and that's when it's bright. When it expands it's cool and that's when it's faint. This is not intuitive. Anyway, it turns out that at certain times in the W Virginis cycle, you get double absorption lines, and what's happening is the following. There's a shock wave going out through the atmosphere of the star, and when it goes through the atmosphere there is the cool material in front of the shock wave and a hot material behind the shock wave. The material behind the shock wave is moving outward and the material in front of the shock wave is moving inward so they're displaced, and that's why the lines are double. And these two sets of lines have very different characteristics. One is from a cool region, the other is from a hot region.

McCray:

So you would have different ionizations in those different...

Abt:

Yes. And so the spectrum would look very different. So here you have a unique situation in which you can actually see in this transparent atmosphere a shock wave moving through it which takes four or five days to go through it. And at first you see mostly lines from above the shock wave and very little below. As the shock wave moves a little farther you start getting absorption lines behind the shock wave, and they become strong and the ones ahead of the shock wave become weaker until finally the shock has gone all the way through. So by looking at these two sets of spectra, you can determine the conditions before the shock and behind the shock. It was really the first time in astrophysics in which you could see before and behind the shock wave at the same time. So that became the thesis.

McCray:

And doing this work, you were using the 100-inch?

Abt:

Yes.

McCray:

I'd like to come back to the use of that telescope at some point. At this point then Allan Sandage had gone on and he was working with Hubble and learning to use the 200-inch.

Abt:

He was using the 200-inch. They told us as students we couldn't expect to use the large telescopes. We would have to be satisfied with the 60-inch. The first two theses were with 100- inch and 200-inch. Well, I think Sandage worked first with Hubble's plates, and then he started taking plates on his own. And his thesis actually was on a globular cluster, a color-magnitude diagram of M3, which he did in the old laborious way of using an iris photometer with photographic plates and he measured thousands if not tens of thousands of stars. Which in those days was very boring, but if you had the determination, you learned a lot about the globular clusters. But this was the beginning of the time in which photo-electric photometry was coming into astronomy. Photographic photometry gave you moderate results, but photoelectric photometry gave you better results by a factor of, say, four or five in accuracy.

McCray:

Were there any people there who were particularly important in introducing new instrumental techniques?

Abt:

Yes. They realized that they needed somebody who understood photoelectric photometers and they were under development stages and so Mount Wilson hired a physicist by the name of William Baum. He is the one who built photometers. Sandage cooperated with him because he realized he needed some photoelectric standards; otherwise his photographic work might have systematic errors.

McCray:

So after graduating in '52 from Caltech, you went on then to Lick Observatory in '52, '53.

Abt:

Yes.

McCray:

At that time they were building the 120-inch or making plans for it. Did you get to use that at any point?

Abt:

No. It was still under construction. I should say that Sandage— Oh, another person who came up and taught us was Schwarzschild. He taught a course to us. And Sandage in particular became very interested in stellar interior models. We were introduced to that by Stromgran, but Sandage went off in his last year to work with Schwarzschild at Princeton. And that's when Schwarzschild was using large computers for the time and to get stellar interior models. And for the first time they were able to explain why stars left the main sequence. That is, the stars had exhausted the hydrogen in the cores, the cores became inert as far as nuclear reactions are concerned and became more and more compressed. And the hydrogen burning was in a shell around the core. This is what they did, Sandage and Schwarzschild. So he basically took off a half year or so, went to Princeton and worked on that problem. That's why he graduated later than I did.

McCray:

Can you give me just some sense what it was like using a big telescope at that point?

Abt:

Marvelous.

McCray:

Why? It seems that today we have all of these new telescopes that are being built, huge telescopes but it seems that the astronomer and telescope are separated somewhat by computers and all sorts of other hardware. I'm curious what it was like to use a big telescope at that point in time.

Abt:

Well, you became much more aware. You were close to the telescope, you were working at the focus. You weren't in some closed room somewhere else out of sight of the telescope. You worked in the cold because you didn't want to be disturbing the seeing. And exposures are long, and you had to guide on the objects. So you may spend four, six, eight, ten hours staring through an eyepiece in the cold (not terribly cold because California is not that bad). It was very tedious. But also it was somehow mysterious. Here you're looking at something you knew was very far away and you're trying to figure out what's going on. And you were anxious to get some good materials so you could interpret this. Astronomers usually had classical music playing, and there was music at nighttime. And it was quiet. And a few lights around but dark in general. It was all very nice. Certain pieces of music I associate with being in the domes, with certain domes.

McCray:

Such as?

Abt:

A Serenade by Reger, which you never hear but it's a marvelous piece.

McCray:

Do you associate certain pieces of music with certain telescopes or certain objects to look at?

Abt:

Well, some of them sort of impress me.

McCray:

When you went to Lick, did you continue along the same line of research?

Abt:

Roughly. At that time positions for graduate students were usually arranged by the professors. Your professor contacted people at other places and said, "I have this student who is coming out. Do you have an opening?" And he'll say yes, we have such and such an opening. And so it was presented, it was offered without my ever having to make an application.

McCray:

So a student would be fairly dependent upon his or her advisor to secure them a post-doc.

Abt:

Yes.

McCray:

I guess it became pretty important to get along with your advisor.

Abt:

Oh sure.

McCray:

I'm guessing your salary also went up once you got to look beyond that?

Abt:

Yes. My salary started out at $4,900 a year. That was a big step for me. So for the first time I could afford a car. At Caltech it was a bicycle and 3,000 miles a year.

McCray:

That's a lot of bicycle tubes, I would imagine.

Abt:

Yes. At Lick, of course the only telescopes they had were two telescopes: a 36-inch refractor and a 36-inch reflector. The reflector was Crossley; the refractor was a well known one. And they had an Astrograph telescope. But there was a nice spectrograph on the 36-inch.

McCray:

The Crossley.

Abt:

No, not the Crossley, the refractor. It was the Mills spectrograph it was famous because it was the standard for radial velocities in the early part of the century. It was given by a lady by the name of Mills. But it was the international standard for radial velocities because early in the century that was what they mostly did at Lick was radial velocities. And this spectrograph was still in use. I used that on some bright RV tauri stars, which were like classical Cepheids but longer periods and less regular.

McCray:

RV tauri, you have some publications on that in 1955 here.

Abt:

Yes, and I found out that those two had double absorption lines and they also have this shock wave business going through it.

McCray:

Was that surprising?

Abt:

Well, I thought that if W Virginis stars have, why not look at RV tauri stars, which were similar. They're also found on globular clusters. And so yes I did that, and I did a few other things, smaller projects.

McCray:

You went from there to Yerkes so you ended up back where you started.

Abt:

Let me say a few things about Lick. In those days, all the staff was on the mountain top, Mount Hamilton. It was marvelous for astronomers because they're close to the telescopes and they could observe and then go home easily, but the families didn't like it. It was too isolated for the wives, and there was a one-room school for all grades and that's not the best way to get an education.

McCray:

Who would teach the kids?

Abt:

They had a schoolteacher. The students on the mountain would all be in this one class.

McCray:

Were you married at this point?

Abt:

No.

McCray:

I don't know if you are married.

Abt:

No. But for astronomers it was great. On many telescopes they split the nights, one person would be on first half and another person on second half. It works well. For instance, if you have it for one night and half the night is dark and the other is moonlit, you changed equipment during the night. So whether you were first half or second half it was nice to get close to the telescope. Later on they decided to move astronomy to another campus at the University of California.

McCray:

Santa Cruz, wasn't it?

Abt:

Yes. That's when they built up the Santa Cruz campus and started an astronomy department. They moved the Lick library there and astronomers moved there.

McCray:

What was the response of that move?

Abt:

Mixed. Families liked it, the astronomers were not that enthusiastic but they weren't given much of a choice. This is what California decided to do and they did it. The road up to Lick is horrendous.

McCray:

Yes, I've heard that. So the astronomers would then commute up to their..

Abt:

Yes, or they started doing astronomy in Santa Cruz and only went to the mountain for observing. There's a nice story that the guide up there tells. There's a family of three people, a father, mother, and son who were driving through San Jose. And the wife wanted to do shopping and the father spotted a sign that saying Lick Observatory 19 miles. And so he said, "Okay, you go in the department store and do your shopping and Junior and I'll run up to the observatory and look around and come back here. We'll meet you in an hour." Well, they've gone up this horrible road. Once you get on it you can't turn around. They got up to the top and made a U- turn and started down. And the guide says, "Hey, don't you want to see the telescope?" And he says, "Well, while we're here," and he told him the story. It was an hour and a half and they had just gotten to the top of the mountain.

McCray:

I guess someone was waiting at the department store for a while afterwards. So how did you end up at Yerkes? You were at Yerkes with W. Morgan and Aden Meinel.

Abt:

Yes. Well, I couldn't find a job.

McCray:

What was the job market like for astronomers?

Abt:

Well, it's never been very good.

McCray:

Was it particularly bad at that point or had it just always been depressed?

Abt:

I think it's always been difficult except during the Sputnik times. In fact for astronomers, a few get jobs at observatories or universities but most of go elsewhere. Later on NASA started picking up a lot of astronomers at their centers. So I couldn't find anything right then, and I heard that Meinel had an opening at Yerkes. That was something entirely different. He was interested in aurora, (Northern Lights), and he wanted somebody to help on that.

McCray:

I didn't realize he was interested in that. That's not something I knew about him.

Abt:

Yes. He made some big discoveries partly because he was a superb optical designer and he could design extremely fast systems. And with a fast system he could get spectra of aurora, which are faint. And also the light of the night sky, which he worked on. His primary associate on that was Joseph Chamberlain.

McCray:

How did you end up there? I mean how was the arrangement for you to go from Lick to Yerkes? Did you contact Meinel?

Abt:

Again I think people made the arrangements. Of course I was asked, but there weren't many opportunities and they said, "Well, there's an opening at Yerkes for somebody to work on Aurora. I did a lousy job for Meinel.

McCray:

That's an honest appraisal. Why do you say that?

Abt:

Well, I wasn't terribly interested in aurora and sort of did a minimal amount. But I had the opportunity to observe at McDonald with the 82-inch spectrograph, which I did, and I continued to do spectroscopy on stars; and that was wonderful. But it took most of my time.

McCray:

Not leaving a lot of time for aurora studies.

Abt:

Well, yes. Anyway, I did a lousy job. I feel guilty.

McCray:

So did Aden and them punish you by sending you off into the desert to find Kitt Peak?

Abt:

No, not quite. What happened then is Aden, of course, would go from one project to another.

McCray:

I've only corresponded with him through e-mail and many people have talked about him, but he seems to be is a person with many ideas. That seems to be where his interest is. Is that feeling accurate?

Abt:

Yes. He was primarily interested in instrumentation, and this led to a lot of possibilities. And one was a possibility of building a Schmidt camera on a sort of micro scale instead of spreading the light out over a large area. About that time Kodak realized, after astronomers told them this, that their plates had much better resolution than they thought. They used to think that the resolution of photographic plates was 20 microns. And so everybody designed optics for 20 micron resolution. But then and I'm not sure how this came about, who clued them into this first, but they realized that their plates often had a resolution of eight or ten microns and maybe even better for the best plates. So Meinel started designing equipment which would take advantage of that high resolution. Rather than build a large telescope which could give you large spectra, he designed a small telescope which would give you small spectra. By using the good plates they would give you equivalent spectra. It's called a Micro Schmidt. So that was built but never really adequately used. He and Meinel had this joint project on that. And Meinel also had a project on getting H alpha interference filters photographs, direct photographs of the Milky Way. I started it at Yerkes and then it was taken to McDonald and I spent a winter at McDonald taken photographs.

McCray:

Would you drive back and forth between?

Abt:

No, no. I spent the whole winter there. So I was working then on that project rather than the aurora project. And got beautiful plates. I don't think much was ever done with them. I packed them up and sent them back to Yerkes. At McDonald I even photographed three stars of the Southern Cross. Refraction brings them above the horizon. At times the conditions at McDonald Observatory are excellent and with a latitude of 30 1/2 degrees, and the Southern Cross is partly above the horizon. And so you can photograph three stars. I didn't see them, but they showed up on the plates after development. We also photographed the Gum Nebula.

McCray:

I'm not familiar.

Abt:

The Gum Nebula is a super nova remnant which has dimensions of 30 degrees by 40 degrees. That's huge—that's a good chunk of the sky. It's faint. It was first found by an Australian by the name of Colin Gum. Later on he was killed in a skiing accident in Switzerland. But it's still called Gum Nebula.

McCray:

This was work that you were doing at McDonald?

Abt:

Yes. Well, there was one paper that came out by Stromgren and Morgan. But the Gum Nebula is spectacular. Most people didn't have a wide enough telescopic field. They would see just a little section of it. Because they had a field of two degrees, three degrees at best. But the Gum Nebula is 30 by 40 degrees, so it's hugh. This small Schmidt camera that I was using had a field of six degrees so by mosaicing we could photograph the whole thing. And so in that paper with Stromgren and Morgan, we got the first full composite picture of what it was.

McCray:

What does it look like? Was it wispy?

Abt:

A filamentary wispy thing.

McCray:

How long would your exposure have to be in order to capture that?

Abt:

We had two filters. We had a red filter for each mount and then we had an interference filter. The red filter took about 20 minutes, and the interference filter took four hours. So we had this little Schmidt that Aden built attached to another telescope.

McCray:

Do you have a picture of it?

Abt:

Oh, it's in the Ap J.

McCray:

Okay, I'll have to look that up.

Abt:

I had nice observing runs at McDonald. They were usually two weeks long.

McCray:

How would that go? Would you be on the telescope for a two week stretch?

Abt:

Yes, usually. Once I had one of four weeks. They had two week observing runs and they offered two successing ones to me. And that turned out to be a very good run because I got interested in the question of whether most or all supergiants are variable pulsating stars. Now we know that some supergiants are called Cepheids or W Virginis stars. But then I was wondering about the other stars that are neared to the Cepheid strip. In an H-R diagram the Cepheids form a strip and I wondered about the stars left and right of that. So I picked a dozen or more stars and got Coude spectra with the 82-inch night after night for the four week run. I found out that they're all variable. The brighter they are, the larger amplitude of the radial velocity variations. They're also light variables but that was also found later on. I was using radial velocities and found out that all over the H-R diagram all the super giants are variable and determined periods for them. I found out how the period varies as function of luminosity and tempertaure. It's called variability of supergiants.

McCray:

Was there anybody else at that time that was doing similar work on that topic?

Abt:

No, no. That was the good old days in which when you picked some project, you had a fair amount of assurance that no one else was working on it because you knew what everybody was working on. There were only a few hundred astronomers in the country you knew what they were doing. So when you picked something, others would keep their hands off.

McCray:

So there wasn't any poaching of topics.

Abt:

No. It's the opposite of physics because in physics if there's an important idea that develops, several people jump on it and then the competition is to see who can finish first.

McCray:

Why do you think that difference is?

Abt:

Because in astronomy they're more interesting projects to work on than there are people to work on them. In physics there are fewer interesting projects than there are people to work on them.

McCray:

It's hard to imagine, I would think, today of being able to have a four week observing run on a good sized telescope. It seems that people are competing for two day stretch or a three night stretch or something like that.

Abt:

Perhaps you know something about the McDonald Observatory. It was given by a bank Vice President, the money was given to the University of Texas to build a telescope.

McCray:

That's about as much as I know about it.

Abt:

He gave his money and it's not clear why he did that except he had a girlfriend who was a teacher and interested in astronomy. When his will came up, he didn't seem to have any heirs, and he gave this money, almost a million dollars to the University of Texas for an observatory. Well, once this became known, several distant relatives appeared out of the bushes. They contested this saying anybody that leaves his money for astronomy must be crazy. Well, they had a court case on this and they brought in an astronomer by the name of Joel Stebbins.

McCray:

He did work with photo-electric devices.

Abt:

Yes. And he had to get up in front of the jury of ranchers and cattlemen and explain why giving money to astronomy wasn't completely idiotic. He mentioned something about weather predictions and they won the case, but they made an out-of-court settlement with, I think it was, four relatives. And they gave $50,000 to each one. Now this is during the depression in which if a person was earning $1000 or $2000 a year you were doing great. So each of these four got $50,000 and they went berserk. Now if you figure it out S50,000 during the depression might get 2% interest so it gives a $1000 a year. And so it's hardly enough to quit your job. But they of course quit their jobs and they bought cars and houses and pretty soon the money was gone. And most of them got divorced and it just wrecked their lives. But the remaining money was given to the University of Texas to build an observatory. They had no astronomers there. This was in the 1930s. So they got help from the University of Chicago which had a well known group of astronomers. Otto Struve and George Van Biesbroeck took this over. Van Biesbroeck went down to Texas and picked out a site for the observatory, after looking around a bit, and picked a very dark site in a sparsely populated county in Western Texas called Fort Davis County. And the telescope was built by Warner Swasey. It was a very solid, well built piece of equipment. And there was a contract between Chicago and Texas that Chicago would maintain it and use it, but Texas would own it. And it wasn't until the 1960s that the University of Texas started to build up an astronomy department and then they wanted part of the time. A new contract was negotiated and it finally ended up in which Yerkes was buying time from Texas. More recently they've dropped that.

McCray:

When was the 82-inch finished?

Abt:

Late '30s. I remember '37, but I'm not sure.

McCray:

How was it as an instrument to use versus the 100-inch at Mt. Wilson? How did the two compare?

Abt:

The 82-inch is much easier to use.

McCray:

Just smaller or the way it's designed?

Abt:

Well, clutches and the accuracy in the settings. And the 100-inch was floated on a film of mercury and it took an expert to set it. The 82-inch anybody could learn how to use in a few minutes. In fact, a number of nights I used it myself without a night assistant.

McCray:

So it was a fairly user friendly type of...

Abt:

Yes. And then Hiltner built a very marvelous spectrograph for it.

McCray:

You noted on your CV that you helped design five different spectrographs.

Abt:

For Kitt Peak and Cerro Tololo, Yes.

McCray:

We can come to that later. During this time you were doing a lot of spectroscopy. Did this help you with later designing them?

Abt:

Yes, sure. I basically worked from Meinel's designs, his ideas.

McCray:

So tell me about finding Kitt Peak. I mean I know the story has been told in many of—

Abt:

Let's finish up at Yerkes. After that then they offered me an Assistant Professorship and I started teaching.

McCray:

You were at Yerkes '56 to '59, assistant professor.

Abt:

Yes.

McCray:

In astronomy?

Abt:

Astronomy. And I started teaching courses to graduate students.

McCray:

Did you like it?

Abt:

Yes, um hmm. I taught courses in radio astronomy, I knew nothing about radio astronomy but somebody had to and so it was just a development in the field and so I learned a little faster than the students. It was fun. Several other courses, variable stars and so on and so forth. I had some very good students, who included Carl Sagan.

McCray:

I didn't know he went to school there.

Abt:

Jack Brandt, Eugenio Mendoza, Arnie Heiser, and various people who names I'll know later on. So it was kind of fun. But then the idea of Kitt Peak started to come up. And that started with a suggestion by John Erwin at a photo electric conference in Flagstaff in 1954. He said we have observatories in poor climates, Harvard, Yerkes, so and so forth. Why not have an observatory in the best climate we can find and let all astronomers in the country who want to use it come to it? And another thing that made this possible at that time is the beginning of air travel. Normally to go across the country it would take you three days by train.

McCray:

So the possibility for people to travel from different institutions to a common site was doable.

Abt:

So it became possible to go from any part of the country to another part in one day. A lot of universities only had one or two astronomers. And an astronomer couldn't during the school year take off two weeks to go off and observe somewhere if he had to take a train. But if he could get there in a day and then have a three or four night observing run and then go back, it would only take part of a week.

McCray:

And it wouldn't interfere with the teaching schedule.

Abt:

Generally not. Somebody would pinch hit for him or give a test. So the idea of having an observatory for all the astronomers in the country made sense. And so with that, the initiative for that surprisingly came from Robert McMath.

McCray:

Who was at Chicago?

Abt:

Michigan. He was a solar astronomer. Actually he was a businessman who got interested in solar astronomy and built up an observatory there. And he was somewhat of an entrepreneur.

McCray:

Did you know McMath?

Abt:

Yes.

McCray:

What was he like as a person? He was involved with numerous government science policy committees.

Abt:

A very capable administrator.

McCray:

Where did his interests in astronomy come from? He seems to have been interested in it more than just at the amateur level. He really pursued it almost as a second career it would seem.

Abt:

I have forgotten his background. He had a company that made bridges.

McCray:

I'm not sure.

Abt:

In the Detroit area. Anyway he took the initiative. As you say, he'd been on government committees. He took the initiative of getting a grant with the NSF to look for a site for the National Observatory. And he hired Aden Meinel to be the basically the first director and then run the site survey.

McCray:

How did he know Meinel? Was it from their...

Abt:

I've been working for him at Yerkes.

McCray:

No, I mean how did Meinel know McMath.

Abt:

Well, it was primarily an instrumental problem and Meinel was know as the wonderkind of astronomical instrumentation. Developing the equipment to observe things, get the spectra of things as faint as aurora in a night sky. I tell you that was a real feat.

McCray:

Aden's wife Marjorie—her father was an astronomer, a solar astronomer I think.

Abt:

Yes. Pettit.

McCray:

Right. And Marjorie's also into astronomy and optics.

Abt:

Yes. I think they met at the Pasadena City College. They married and they raised seven children.

McCray:

They had a huge family. I can't remember how many kids.

Abt:

Seven kids. Joe Chamberlain said when the seventh came along, I thought you'd stop at half a dozen but I see you're going all the way now. Well, they came from big families and they like big families. And they had the patience and the income and the intelligence to pass on to their children. Oh something else that happened and that is while I was at Caltech I became acquainted with the Southwest. And became acquainted with a Bill Miller who was a photographer at Mount Wilson. He was basically the only person who did real research on photographic processes. They needed toget the most from their telescopes and so he is the one who worked with Eastman to improve emulsions. He got the first really good color photographs with the large telescopes. Normally if you take a long exposure, the colors come out wrong. They come out too blue.

McCray:

So the plates were more sensitive in the blue.

Abt:

Well, the rest of the process involved is different for the blue and the red. And so he allowed for this with laboratory experiments. He modified the photographs to give you true colors. He also had a jeep and he liked to look around the Indian country in the southwest. He got me interested in it too. He started a series of explorations of the Indian ruins in the Navajo country in Northern Arizona and Southern Utah. And on one of those trips he found what is probably the first Crab Nebula super-nova petroglyph.

McCray:

Fantastic. Where did he find this?

Abt:

Well, we found it in White Mesa inside a cave and there's a crescent moon and then there's a big round thing right next to it. And he reasoned that crescent moons are pretty scarce in Indian petroglyphs. They show animals. They show geometrical figures. They show people. They never show buildings. They never show plants and they rarely show astronomical things. And so he said, here's a crescent moon and here's a big round thing. Could this have been the Crab Nebula from1054 AD. The time was right. That particular cliff dwelling was inhabited in the 11th century. He worked with Walter Baade and they figured out and according to the Chinese records or people's interpretations of those, the Crab Nebula was first visible on July 4th in 1054 AD. So Bill said where was the moon at that time. With help from Baade, they computed where the moon was and it turned out to be it was only within two degrees of the Crab Nebula and it was an crescent phase. Actually it was turned the wrong way. But he argued that the guy looked at this in the sky and then went into a cave and maybe he forgot which way he turned. And he drew a big circle which is our cartoon impression for something bright. You know, if it's bright you just show spikes on it or you show something big. So he thought that this was evidence of the Indians portraying the Crab Nebula supernova of 1054. The Chinese records which tell on the fourth day of the seventh lunar month in the eighth year of the rein of emperor so and so the guest star was brighter than ???, which was some star in some come constellation. You can sort of reconstruct the light curve from that. There were no known European records. But Jack Brandt, in particular, found a whole bunch in the Southwest by asking forest rangers. A friend who is living with me has been working on this recently and there's a recent paper by Jack Brandt in which he says maybe it wasn't July 4th. They found some European records which may have indicated that it was either in April or May rather than July. And this makes a big difference. Whenever it was, it was either seen early in the morning just before dawn or in the evening just after sunset. So it was in opposition with the sun. And now there's some doubts as to whether it was really July 4th and some suggestions that it could've been in April or May when it was first seen. But it was certainly seen in July. And this makes a big difference because the crescent moon was turned differently before new moon and after new moon. So these things are taking a little different view point. But anyway, the Crab Nebula supernova is a byproduct of what we're doing. We were looking for Indian ruins in the southwest. It was canyons around there. They were all relatively unexplored territory. We would collect information about the ruins. We did no excavation at all. We'd pinpoint on aerial photographs and maybe do a little surface exploration and then gave all the information to the museum in Northern Arizona in Flagstaff. So we spent summer vacations doing that.

McCray:

That's a nice way to spend your summer.

Abt:

Well, yes we'd tour two or three weeks at a time. It was done by jeep or horseback or walking. So that is why I had a jeep by the time I got Yerkes. That was my choice of vehicle. And I knew something about the Southwest and so that's why Aden asked my do to part of the site survey. So I left Yerkes for a short time in 1955 and '56 and worked on a site survey. We realized that for clear weather there's two places in the country, the Southwest or Florida. But Florida has no mountains and the empirical evidence was that for good seeing or small sharp images you had to go up on top of the mountain.

McCray:

Dry sites as well?

Abt:

Yes. So that left out Florida and so we concentrated on the area from basically West Texas to California. I started from McDonald Observatory and hired a pilot by the name of Casperus who was a veteran pilot from around there. He logged off 33,000 hours of flying. He would do things like taking his little single engine, his Cessna flying around the cliffs. There was a bounty on eagles and he would remember where he shot them and pick them up later on. He'd been a pilot in the first World War. So I hired him at the huge expense of 10 cents a mile. So we went from McDonald Observatory through Southern New Mexico and Southern Arizona. Using aeronautical maps looking at the nature of mountain sites, taking photographs, and just noting the vegetation and looking at the characteristics that we could. We covered 2000 miles and that cost us $200. It was a single engine, Cessna 140. It has one engine with four cylinders. One the way back one of them started to miss so he made a emergency landing. He radioed his wife and she came. By the time she came, he figured out what was wrong. Two spark plugs were dirty on ne of the cylinders, but I went back with her. Anyway, an interesting trip. Then from there on, I went myself to these various places that we'd pinpointed.

McCray:

Were you traveling by yourself?

Abt:

Yes. I went to each of these mountains to photograph them from the base and different views. Some of them I climbed and occasional stayed over night at the top to see what the surrounding city lights were like. Just a preliminary survey.

McCray:

Was Kitt Peak looking like a good choice at this point?

Abt:

Yes, it looked good. This ended up in picking five or six sites. One was in California, the others are all were in Arizona.

McCray:

So it was all in the south around the Tucson area in Arizona?

Abt:

No. One is up near Kingman in northwest Arizona. That was a competing site for Kitt Peak. Another one was near Flagstaff. Another one was near Winslow. Another one was north of Dunlop. My part was just to pick preliminary sights. Of course Aden went with me on some of these. And we decided to eliminate the one in California on grounds that California and Arizona have very different weather patterns. California has a lot of storms in the winter time and superb summers. Arizona has better winter weather but they have summer thunderstorms. So we thought that if there's another major observatory it should perhaps be in a different weather pattern.

McCray:

To compliment the California weather pattern.

Abt:

Yes. The site survey continued for a couple of years after I left. I left in 1956.

McCray:

How as the site testing done?

Abt:

And it was done in two ways. One is to build the towers. What they wanted to know was seeing quality, how big the star images were. So Meinel said, "Wait a minute. We can do this with Polaris. We can use a Ronche screen." Do you know what a Ronche screen is?

McCray:

No.

Abt:

It's a piece glass with sharp black lines, transparent between.

McCray:

How do you spell it?

Abt:

R-o-n-c-h-e. And he had a telescope which he designed so that Polaris, not being at the pole, (it is two-thirds of a degree from the pole) moved around a small circle. The image of that would be projected on one of these Ronche screens. It would be eclipsed byo ne of the lines and transmitted by the gap. But if a star image is big, then it would cover several of these. And so you would have a photoelectric pattern with a photometer on the tower which would produce one of these Roman designs.

McCray:

Right. Up and down, up and down.

Abt:

Yes. But if the scene was poor, then you just got a sort of a sinosoidal curve.

McCray:

Right. So you could also vary the width of the lines to correspond with the size of the object you're looking at.

Abt:

You match that too. So no moving parts. Just Polaris going around in a circle projecting onto a Ronche screen, photoelectric photometer behind it, and you get a measure of how the seeing was. And of course they put these in a tall tower because they wanted to get away from heat currents from the ground. So they built towers that were 100 feet high approximately. And they built these at four or five different sites. And that was one of the primary criteria of determining the seeing at different sites.

McCray:

That's a remarkably elegant solution.

Abt:

Well, that's typical of Meinel, simple solution. And he found out the sites up near Winslow had terrible seeing. And Flagstaff was not too good. They ran into trouble in the Sierra Ancha Mountains. And it finally boiled down to either the site in the Huachuka Mountains near Kingman or Kitt Peak on the what is then the Papago Indian Reservation. And they also did some photoelectric observing for sky transparency. For that they developed 16 inch telescopes that were put on trailers. They would move it to a site, align the telescope, and the observer who was primarily J. C. Golson, did photoelectric photometry and from that he got measured the quality of the sky as far as transparency is concerned.

McCray:

How would you get a 16-inch telescope up a mountain?

Abt:

It was built in a small trailer which was about three times the size of this desktop.

McCray:

Just pull it up with a jeep or something?

Abt:

Yes, pull it with a truck or a jeep yeah to a site. Of course they had dirt roads up to these sites. So they did the photometry; and that was other measure. So after several years of this, they looked at these two sites on the basis of a 18 criteria and Kitt Peak won by a land slide.

McCray:

There was no serious debate over one or the other? It was pretty clear that Kitt Peak won.

Abt:

Yes By that time they'd started an organization called AURA, Association of University of Research in Astronomy, Inc., which had representatives from each of the universities that had observatories of their own and had astronomy departments.

Abt:

Initially there were seven universities, which were Harvard, Yale, Princeton, Michigan, Chicago, Indiana, Berkley. And then later on they added more and now there's dozens of them.

McCray:

Right, including some countries I think as well. I know Australia joined it.

Abt:

No, Australia joined the Gemini Project. These formed a board of directors that made important decisions. Such as which site to pick, what to build, and so on.

McCray:

You came back then in '59.

Abt:

Yes, I went back when the first part of the site survey was finished. It was going to be a long, you know the rough survey, it was going to be a long interval, several years of testing and that was not very astronomical so I went back to Yerkes and taught.

McCray:

Never Chicago.

McCray:

When we ended yesterday, you were just about to make the move permanently to Tucson to Kitt Peak in 1959. So why don't we pick and go from there.

Abt:

Okay. Initially the observatory was conceived of, in Meinel's eyes and others, as a photoelectric observatory where they did photometry. But one cannot do much photometry when the moon is up because the sky's too bright. So then why not do spectroscopy when you can't do photometry? Therefore they needed a spectroscopist and Meinel asked me to join the staff. Of course, McMath who had an interest in this, wanted it too. It was an excellent place for a solar telescope. Should we repeat it? So in '59 they asked me to join the staff and I thought it was a great opportunity so I accepted.

McCray:

What topics were you involved with whenever you first arrived? What types of research were you doing?

Abt:

Well, at that time I was working on the frequency of binaries among solar type stars. And we didn't have any equipment in '59 that I would interested in using. No spectrographs yet. And so I went over to Mount Wilson and observed there frequently. But I started this project to figure out what fraction of the stars like the sun have companions and it turns out to be high. Like roughly two-thirds.

McCray:

So would our star be an anomaly in a sense as not having a binary?

Abt:

Slightly anomalous, Yes.

McCray:

Okay. When you first joined the National Observatory, it was obviously quite different from what it is now. What was it like as a facility at that point in time?

Abt:

On the mountain or here?

McCray:

Either or both.

Abt:

On the mountain, they were building a 36-inch telescope. They had a couple of the site survey 16-inch portable telescopes mounted permanently and they were doing photoelectric photometry with those. And the solar telescope was under construction. Here in town they rented office space on Park Avenue and started this building. And only the first part through the next two offices. We moved in here in the Spring of 1960. And I'm the only person in the organization that's been in the same office for that following 40 years.

McCray:

It's quite convenient not to have to move this whole wall of journals that's here to my right.

Abt:

That's right.

McCray:

At this point the optical community was establishing national centers and the radio community was doing the same thing. But the two communities seem to have reacted since then differently. The roles of those two different national observatories seem to have been quite different. Any idea since you were there when they were first starting where that comes from? The differences in the optical and the radio?

Abt:

There was more cooperation in the radio community, support for the National Radio Astronomy Observatory. And I think very few major facilities were built in radio astronomy in this country, which are not involved in the National Radio Astronomy Observatory. In this country, there were universities that were still building major telescopes and there was quite a bit of resentment. People at the major universities felt that they had the expertise, they should get the money. Any good astronomer would be at one of the major universities. If he's at a minor university, then he's probably second or third rate and to build telescopes for such people is a waste of money. So that there is continuous resentment up to the present of money going to the National Optical Astronomy Observatory compared to going to the universities that have their own facilities.

McCray:

How do these conflicts get played out in the arena of building new facilities or just managing them?

Abt:

Well, I'm sure there's campaigning with the NSF, which funds Kitt Peak, to give more money to grants and less money to the national centers. The way it was set up with AURA as being the organization that set the policy, they as you recall were representatives from the major universities. And those people had conflicts of interest. If they were on the board of directors of AURA, they still felt that their universities deserved the money and so they had mixed feelings. And that, in ways which are hard to pin point, has led to problems.

McCray:

Hard to pin point because?

Abt:

Well, you don't know what goes into the decision making of the allegiances to AURA compared to their home universities. For a long time they were micromanaging Kitt Peak. I recall that there's a janitor who was 65 and over and needed to work longer because he had a sick wife and so every year the whole AURA board had to approve an extension of his appointment for another year.

McCray:

When you first began, here when the National Observatory was getting started, was time on the instruments allocated differently than the way it is now? How would someone get time?

Abt:

Not fundamentally differently. There was a committee set up to read the proposals and to decide on which ones were the most meritorious. One thing that's not widely advertised, that is that we made time available to people outside the United States. They had to more than compete with the domestic requests but they were granted time. I'm sure that some people if they looked at that would say why are we giving money, spending money on helping researchers in other countries? But it was never really brought to the floor and so it's been a practice that's continued.

McCray:

Are there particular countries or areas of the world where astronomers outside the US come from in particular?

Abt:

No, no. Just the usual ones, particularly initially Europe did not have good telescopes and they did not have good locations. And those two things go together. In past decades they have, of course, built observatories in Chile and the Canary Islands and other good sites worldwide and they now compete with the United States in quality of equipment.

McCray:

By 1973 the National Observatory had the second largest optical telescope in the United States, I guess. The 158-inch was commissioned in '73. Then the one in Chile was commissioned in '74. What do you recall from that period of the planning and getting ready to build one of these?

Abt:

Well, I think they did a very good job. Dave Crawford was head of the projects, and the project was completed on schedule and on budget, both of them. Maybe there was difficulty with Chile because they're subject to the exchange rate and they were forced to use the official rate which is sometimes unrealistic. So I don't know the details about budgeting there, but basically they did a very good job in building these.

McCray:

Did you get to use the 4-meter?

Abt:

Some, Yes.

McCray:

What was it like to use or what is it like to use?

Abt:

Well, it's the first time I'd ever been in a prime focus cage and it's an interesting way to observe. It's also impressive because then you have the whole field in front of you so it's a marvelous thing to see. But my type of research didn't lend itself to that kind of telescope so that I haven't used it since then.

McCray:

What types of instruments were you more inclined to use?

Abt:

Coude spectrographs and Cassegrain spectrographs. We built a Coude spectrograph for the 2.1 meter telescope, mostly Meinel's design. He oversaw most of it. It was built and has been a superb instrument. It's an amalgamation of the best features from other Coude's spectrographs. Meinel's spectrographs are the fastest ones available. About then, it was reasoned that the spectrographs sat idle part of the month while the telescope was being used for other things. And the characteristic of a Coude spectrograph is that the speed depends only upon the diameter of the mirror, not the square of the diameter. The light gathering power depends on the square of the diameter of the mirror. But the Coude spectrograph's speed depends only on the diameter. And therefore if we use the 36-inch mirror to send light down the Coude spectrograph, it should be slower only by a factor of 84 over 36, which is about 21/2. And so that was built, started by Art Hoag to send light down to the Coude spectrograph. And since then it has been basically the most trouble free instrument on the mountain. Month after month, week after week when they have meetings and they discuss all the things that went wrong with various telescopes and how to cure them, the Coude feed needs no fixing. Once a year we wash or aluminize some optics but otherwise it's essentially a trouble free. It is a very easy system to use so it's been marvelous. High resolution, fast, everything you want in a spectrograph.

McCray:

Do you recall anything memorable about designing it or the building of it that stands out?

Abt:

I think this is a sort of an unusual instrument. It's in a room which has 8-inch thick Styrofoam in the walls. Of course it's on a sloped plane because the pole is 32 degrees above the horizon. It's built on 24 inch high I-beams. Three point support, very good temperature control in the room, attention paid to things like if you use Pyrex mirrors and steel they have nearly the same temperature coefficient. And so it requires virtually no refocusing as you go through the year and the temperature changes. At one time it still had the world's largest grating in there.

McCray:

There was a gratings laboratory at Kitt Peak eventually.

Abt:

Yes, for a while.

McCray:

What happened to that?

Abt:

It produced some gratings, I think, for solar and for the Cassegrain spectrographs. But it was one of the things that got dropped when money ran short. It's a difficult business to rule gratings.

McCray:

So when did Aden Meinel leave as director? That was pretty soon after Kitt Peak got going, wasn't it?

Abt:

They had a dedication in 1960 as I recall. And the day after the dedication they fired him. It was tragic.

McCray:

Frank Edmondson and his book on AURA notes that event, but he doesn't give a reason for why Meinel left and I've been led to believe that there was some conflict with him and McMath. Is that the reason for his leaving?

Abt:

Part of it. McMath didn't realize that Aden's wife, Marjorie, was the daughter of Pettit. And McMath and Pettit were very unfriendly towards each other for reasons I don't know. And so when he learned that fact, then he changed his attitude towards Meinel. But that's a personal matter. He's only one person on the board. What happened more specifically is that Meinel's an idea person. He has all kinds of brilliant ideas and he'll try them out, push them to the point where he understands whether they'll work or not and, if they don't work, he drops them. Then he picks up another idea and so on. Now this is good science but difficult for planning budgets. So that the budget people said "what are you going to do next year?" And Meinel says, "Well, let's see. I've been thinking about this idea and thinking about that idea." And they didn't like that. That is what you might call fiscal irresponsibility, that's probably the charge they levied toward him.

McCray:

Then he left there and eventually, very soon came over, I think in '64, with Air Force support and got the Optical Sciences Center started.

Abt:

Yes. He went to the University of Arizona. For a while he was director of Steward Observatory until Bart Bok came. Then he went back to his original interests of optical sciences and got the Optical Sciences Center started. Then he went other places.

McCray:

So who replaced Meinel then?

Abt:

Nick Mayall.

McCray:

Nick Mayall. Okay. And he was around for quite sometime I guess after that.

Abt:

Yes. He was at Lick Observatory, had not had administrative experience. He was pushed forward by C.D. Shane who was president of the board at that time. And Shane thought that Nick was a very level headed person who would make a good director.

McCray:

How did Kitt Peak run differently under Mayall?

Abt:

More conservative approach. Mayall pushed the four meter telescope which is now named for him. I just mentioned that and it worked out very well. He lacked administrative experience and business experience and therefore relied too heavily upon his associate director, whose name was Jim Miller. And people were disgruntled because they said Jim Miller is running this observatory. And there are times in which a decision by an astronomer is needed rather than the business-man because they provide the goal for which direction you're going. Mayall was looked upon as a weak director because he gave way too often to Miller who was a rather forceful person. But that was the easiest time for the observatory, just after Sputnik and the beginning of Space Age, when money was most plentiful.

McCray:

Did this have any impact upon your work at all?

Abt:

Not directly, no.

McCray:

Mayall left then in '71 and was replaced by Leo Goldberg.

Abt:

Yes.

McCray:

I guess I'm trying to get a sense of how the different directors since you've been here throughout the whole stretch, the different management styles and approaches to leading the place that these people had.

Abt:

They were all very different. Goldberg had visions, and he wanted to push the observatory in certain directions. He was in favor a strong scientific staff and so he brought in good people. But there was opposition later on within the AURA board and most things that were happening behind the scenes for which I'm not too familiar. There's always personal aspects which enter these things. So that when Goldberg quit, they wanted somebody to come in and basically clean up the place. And one of the charges was that the scientific staff had too much authority and too many privileges. A lot of us, for instance, had research assistants who worked for us. And that is an efficient way to do things. Why pay a high expensive astronomer's salary when part of what he does is sort of routine things that can be done by a less qualified person? So, in general, it makes sense to have a Ph.D. astronomer with a good salary to be backed up by somebody to handle some of the simpler tasks. But the other outsiders said, "Hey. The university says scientists don't have these privileges. If they have a grant they can hire an assistant or something like that for post doc." So Geoffrey Burbidge was brought in to sort of clean up the place and to shape up the staff. And as a result, during his time all of the non-tenured staff left. And five of the tenured staff members left.

McCray:

Where did they go? Off to universities?

Abt:

Yes, some went abroad. It turns out that Goldberg had started a lot of projects. For instance, incorporating CCDs into a lot of the equipment and that was unfinished while he was still director. But these things were completed while Burbidge was director and so Burbidge got the credit for these new innovations. During Burbidge's time, which I think was seven years, he never started a single new instrument or new telescope. He complained the budget was too small and he threatened to close telescopes, small telescopes and so on. And then found out at the end of the year, which his advisors had been telling him all along, that he had a million and a half dollars that he haven't spent and that he would lose it. Or perhaps transfer it, but you don't end up a fiscal year with a large amount of money on hand. So those of us here were rather resentful about what Burbidge was doing.

McCray:

Was he effective in getting the user community outside of Kitt Peak satisfied?

Abt:

Not really because there were a number of people who wanted to take advantage of our open policy of allowing outsiders to have telescopes on Kitt Peak. We would negotiate contracts for services like snow plowing and water and other facilities like that. People would come into his office with the proposal to put the new telescope on Kitt Peak and they would leave disgusted and go elsewhere. So he did not foster them. For instance the Apache Peak Observatory wanted to locate here and they couldn't work out an agreement with Burbidge.

McCray:

That's the one in New Mexico?

Abt:

Yes.

McCray:

They eventually got a 31/2 meter telescope.

Abt:

Yes.

McCray:

So originally they were hoping to put that at Kitt Peak.

Abt:

Yes. That's a new consortium. So I hate to fault Burbidge too much. I liked him as a person. As a scientist he's excellent, but administratively he had no experience in administrative before. The little he had was when he had been effectively head astronomer in San Diego for a decade or more and that staff did not grow and they never produced any new facilities.

McCray:

Burbidge left in '84 and was replaced by John Jefferies.

Abt:

John Jefferies.

McCray:

Who wasn't here very long.

Abt:

No. John had a good reputation because he was director in Hawaii and had control of Mauna Kea. And people realized that, in the Northern Hemisphere, Hawaii was probably the best observing site. The three great observing sites now are Chile, Hawaii, and perhaps the Canary Islands. So that each time a new organization wanted to build a telescope on Mauna Kea he'd work out a deal in which the University of Hawaii got a fraction of observing time. So it ends up that it was all rather favorable for the University of Hawaii. And, since he had negotiated all of these favorable contracts, they thought that he would be a good observatory director. But the thing which made him successful was that they had a superb observing site and he would just play it tough with anybody who came in. Here he was overseeing the establishment of another layer of bureaucracy between AURA and Kitt Peak and these several observatories, what is now called the National Optical Astronomy Observatories. So that the solar observatory and Cerro Tololo and Kitt Peak were all part of this new organization and he accomplished that. But otherwise, not very much. But he brought with him his assistant director who was Sidney Wolff and Sidney has turned out to be a superb director.

McCray:

She's been here for quite some time.

Abt:

Yes, 15 years.

McCray:

She's lasted longer than any of her predecessors.

Abt:

Yes. She's an excellent administrator. She holds very efficient meetings. She listens to all of the evidence. She makes up her mind promptly and she defends it. And her decisions are, by and large, very good. And she's also faced this problem with tiny budgets. The budget has been essentially flat for the past decade or more, which means that because of inflation that you can buy less and less each year. Now, in a situation like that, other directors took the attitude of, "Well we'll have to close this and we'll have to stop doing that and we'll have to curtail this" and so on. But she realized that the future for this place and for other large endeavors is to have a consortium, a group of organizations to pool their needs. So she worked out agreements with other organizations and as a result she produced the WIYN Telescope, a 3 1/2 meter and the two Gemini telescopes that are nearing completion. All of this on a declining budget.

McCray:

Going back in time, 1971, you took over from Chandrasekhar the editorship of the Astrophysical Journal or ApJ.

Abt:

Fine.

McCray:

I'd like to talk about that.

Abt:

Yes.

McCray:

First of all, how were you picked as the editor? How did you get the position?

Abt:

That was a complete surprise to me. Let me give you the background on that. As far as the Astrophysical Journal is concerned, Chandrasekhar and even before him Otto Struve had the feeling that the major astronomical journal in this country and the world really should be owned by the American Astronomical Society. Rather than a university press. So they advocated the transfer of ownership. They also realized that perhaps Chandrasekhar could not find a qualified replacement editor in the University of Chicago system. The requirements for an editor are difficult to itemize, but anyway his judgement was he could not find one within the University of Chicago.

They had a search for an editor and offered it to me. And why me? Well, years ago the Astrophysical Journal had come out with a new general index every 25 volumes, that's 12 1/2 years. And I found these very useful. And after a volume of 125 came out, I was looking forward to the next general index and it didn't come out. And so finally I called up Chandrasekhar, who I knew from Yerkes days, and asked if he has plans for a new general index. And he said, "Well, I really didn't have time to produce one." And I said if I produced the manuscript, would you publish it? And he said, "Yes." So I got a half-time help from an assistant by the name of Eleanor Biggs and she and I worked on this.

I did the astronomical part and she did the typing. We typed a general index and that was published. And then comes another five years later and I asked Chandrasekhar if he wanted another general index and he says, "oh yes". So we produced another one. After another five years Chandrasekhar called me up and said, "Would you be willing to produce another general index?" And I said, "Yes" and we did. So that when they started to look for an editor, he realized here's a person who has a conscience about the welfare of the journal. And so that's why he and the committee picked me.

What happened was late in 1970, he called up and asked if I was coming to Chicago sometime. And said if so, he would be willing to meet me at the airport. And I said, "Well, I happen to be coming to Chicago next month, but I'll come to your place." And so I went to his place and he sprung this up on me. And I felt hey, I'm not qualified.

Abt:

He said, "Well, the journal is changing. It's growing rapidly and what I think it needs is more of a person who is the administrator rather than the scientist." He had improved the scientific quality of the journal, but it was obvious the way in which he was operating would have to be changed. He had one secretary and he had one production manager in Chicago and he had one copy editor. And those three people with Chandrasekhar did everything. Now the staff here at times has been six in Tucson, thirty in Chicago, and most of the work is farmed out on subcontracts. So it was a matter of changing the manner in which the journal was operated.

McCray:

Was there ever any idea that you might have to go to Chicago being that the journal would stay there instead of relocating it?

Abt:

No, they never demanded that. They realized that future editors probably could not be in Chicago or would not chose to be and that this could be handled by correspondence. They didn't realize even in that time that with e-mail and faxes and so on that you can do it even better now. So that's no longer a question. So that he asked me if I would be editor. That was on Pearl Harbor Day of 1970 and then I took over on April Fool's Day of 1971.

McCray:

Auspicious dates.

Abt:

Right.

McCray:

Your CV mentions that you changed the refereeing system and I'm curious. How was it done before and what was the change?

Abt:

He depended upon a few top notch people to do all of the reviewing. In fact, I happen to know that one person reviewed 60 papers a year. So he and a small group of elite did the reviewing. Really, with the specialization that's going on in the field now, a person cannot be an expert in that many areas. So that people are overseeing papers in which it would've been better if somebody else had overseen them. I used a much more democratic system. I thought that the referee should be an author and the author should be the referee in the same area. In fact the rough policy is if a person writes a paper then he should review a paper. It's a fair exchange for the work involved. Of course you exclude graduate students and a few other people. You avoid people who used to be experts in their field but they have gone to other things or stopped publishing five years ago. I want people who are currently involved. Now we consult 1,000, 1,200 different people or so each year. So the pool is basically everybody that turns out good papers both domestically and abroad.

McCray:

What has your job been? I mean you began in '71 and 28 years later here you are. How has your job changed? I mean other than the obvious changes like you mentioned with e- mail and faxes.

Abt:

The growth of the journal was spectacular. When I started, we published about 10 cm inches a year. Now it's two meters of shelf space a year. For a long time I handled it myself, but then I realized that I couldn't do it all anymore. So then I got the help of some astronomers whom we would now call Scientific Editors. Three initially and now 15 people. And so what the job involves mostly is to look at the incoming papers and to pick the most appropriate Scientific Editor to oversee the reviewing. And let that person then select the referees and oversee the exchanges between the referees and the authors until a paper is acceptable.

McCray:

How many papers were you receiving in '71 when you started yearly and how many do you receive with submissions?

Abt:

Currently it's around 2,000 a year and it probably in '71 a tenth of that.

McCray:

Pretty substantial growth.

Abt:

The system has worked very well. In fact I think Astronomy and Astrophysics is seriously considering this too because they are now growing to the point that their three editors can't handle all the material themselves.

McCray:

I know that you've written fairly extensively on Scientometrics.

Abt:

That's the name of the journal, which specialized in this field. And that's the science of publication, quantitative analysis of publications and related characteristics. This started out in 1980 when Geoff Burbidge threatened to close the small telescopes because the observatory was short of money. And I thought inherently that small telescopes more than produce their share per dollar and so I made a study with the help of Buddy Powell, who was the Assistant Director. We prorated the cost of telescopes and the maintenance of them. I counted the number of papers that came out for a certain time interval and the citations to those papers. We related that to the dollars that are involved. And we found out that in terms of papers per dollar or citations for dollar, the small telescopes produce much more than the large ones.

McCray:

What was their reaction? That was a time in history when people were really beginning to plan building for the next generation of big telescopes. Did anyone take that as ammunition that we should instead build 50 small telescopes?

Abt:

It was used primarily to keep organizations from closing down small telescopes. Of course a big telescope is needed to observe the most distant things. There are things that you can't do with a small telescope. If you can do it with a small telescope, it's much cheaper to do so. You can get more observing time. It works out that way. So, for a while, that stopped the closing of small telescopes. But then I began to wonder about other things. It's strange that scientists when they deal with science insist on strong evidence before they will believe anything.

But when it comes to administration and policies, they too often go by hearsay and hunches. A good example is the feeling that, you've heard it said that a scientist does his best work when he's under the age of 35. I think that maybe true of mathematicians. That's certainly not true of astronomers. People like Baade who got their best ideas when they're in their 60s and many others. So I did a project to look at the careers of a dozen and a half or the best astronomers that I could find this century. Henry Norris Russel, Shapley, Baade, Humason, so on. And then I looked in the Science Citation Index to see which papers produced the most citations in their careers, and it turns out that, and the age when they wrote those. It turns out that you get a broad flat distribution which starts up in the 30s and falls off in the 60s. So that it means that astronomers produce good papers throughout their careers.

McCray:

To what do you attribute this? You mentioned it's different from mathematicians.

Abt:

I'm not sure if I can tell you. I think in astronomy we often have to accumulate a large amount of information to come to a major result. This information is either accumulate yourself in a lifetime or you acquire it from the literature of other people and assimilate it and come to a major conclusion. So that this takes experience. That certainly is the example Baade, when he figured out that the two population groups. While sometimes in mathematics, I think, a single derivation will lead to a remarkable result.

McCray:

It seems that you're saying in the course of an astronomers lifetime, they acquire a lot of tacit knowledge just from their own experience and that only really begins to have it's payoffs or have it's most significant payoffs when they're in their 50s.

Abt:

Yes, the most obvious conclusions are learned quickly and people can make real insight and say, "oh yes, this must be the way it is". But then after you've skimmed the cream off the top, then there's a lot of hard work involved, obviously assimilating a lot of information and coming to a real analysis theory or whatever you want to call it. But it says that astronomers are productive all their life.

McCray:

That's probably good news for a lot of astronomers.

Abt:

That's right. This should have impact on things like the National Science Foundation, which should give their money to all astronomers. They should nurture them and get them started and keep them going, but they shouldn't turn them off at the age of 35 or 40 or 50 or whatever. The same thing is true for supporting scientific staff. That's one of many projects which I did in which I counted papers, citations, collected information, and asked questions. There are now, I don't even remember, 20 or 30 of those Lifetimes of Papers.

McCray:

Lifetimes of Papers. This was published in Nature in 1998.

Abt:

I did an earlier paper in which I looked at the lifetimes of papers in various sciences. And I found out that papers in astronomy had a half life of 30 years. And I did it for other fields and got half lives of 10 years.

McCray:

Probably genetics, much less than that.

Abt:

And I said, "how come?" So I did some research and it turns out that if you have a growing field, then of course at a later stage, you have a lot more people who are writing papers referring to the older ones. And that artificially makes a lifetime long. And it's not only the field, but it's a sub-field. The lifetime of papers in galaxies now is essentially infinite. In other words the number of citations to galaxy papers stay constant, at least for the earlier ones. But other fields are not growing that fast and that's why they have shorter lifetimes.

McCray:

Do you mean fields as in sub-fields of astronomy

Abt:

Yes, and also other sciences. So that I found out that if you allow for the rate of growth for the different sciences, and correct for that, then you have a lifetime of around eight or ten years.

McCray:

In thinking about publishing changes in astronomy, you and I talked about this the first time that I interviewed you. But I'd like to just come back to it for here. What major changes have you seen? I know you have papers about new wavelength regions and international trends. Is there any broad picture that you've formulated to describe how the whole picture has changed since you began?

Abt:

Yes. The papers, of course, became longer as time went on up until about a decade ago and now they've leveled off. So the average length of papers in the terms of content and format is about 10 or 11 pages and it's true for most of the major journals in astronomy. And of course there has been changes at technology with computers and data processors or word processors and other things like this; you can turn out a paper much more rapidly. And you can have big projects with the fast CCDs. You can observe a lot more.

Of course you observe fainter, but you also end up observing a lot more objects and you have a lot more to say and your paper has more content and people "wonder is this ever going to stop?" Or are we going to have 100 page papers as the routine thing or not. Well, I think the limitation is how much a person can really assimilate himself. You can gets lots of data, you can have tons of printout and so on, but how much you can explain and describe, and interpret. It is the human limitation which limits this and I think that's why papers are not growing longer than 10 or 11 pages. Of course there are some longs one. They are often team efforts, but they take a lot of work to do so.

McCray:

Are team papers or multi-author papers becoming more common?

Abt:

Yes. Early in the century, virtually all papers were single-author papers. Then you'd see pairs of authors. Now, the average is pushing four single-authors per paper. And single-author papers are infrequent, less than 10%.

McCray:

How about multi author papers from different countries?

Abt:

That's amazing. There's another paper here to study the internationalization, namely what fraction of the papers come from different countries, what fraction involve two or more countries. And that has been steadily increasing so that now about a third of the papers involve two or countries.

McCray:

Do you see any frequent pairings of countries? US and England or England and Germany?

Abt:

There's certain obvious ones, but it's happening all over. Astronomy has become very much an international field and I think what happens is astronomers find out that somebody in Austria, for instance, is working on the same area and they join forces and through e-mail they can work together. They may never even meet, but they can turn out a joint paper. Also authors go to other countries to do observing. They go to Chile. The English go to Hawaii and so on. So international cooperation is very prominent now. They also build telescopes jointly, a joint telescope built by several countries. So this shows up. The internationalization is increasing by 1% per year.

McCray:

Wavelength regions? When you began in '71, I'm assuming that the optical was the dominant and probably radio was second. How has that changed? What has become the big growth wavelength regions?

Abt:

All of them are coming to the fore. I think optical is still the dominating one. Because it happens that in the spectra of atoms that we deal with, the richest region for spectral lines is the optical region because that's where there are the two and three electron-volt transitions. So that if you go to the extremes you get far fewer atomic lines. And that means it's more difficult to interpret the results. But the infrared, the radio, now microwave region, the ultraviolet, the x-ray region, and even the gamma ray regions, they're all prominent now. We're using them all.

McCray:

And do you see a trend in papers to have results from all of these different wavelength regions combined to produce a single paper? Is that becoming a trend?

Abt:

It's not too frequent that people observing in different wavelength regions will write a joint paper, but a person who works on a certain object cannot ignore results from another wavelength region.

McCray:

One of the reasons I was thinking about this was I noticed the working papers from the last decadal survey, which people call it the decade of the infrared and I'm wondering has the last ten years been the decade of the infrared?

Abt:

Partially, but that was in 1991 wasn't it?

McCray:

Yes.

Abt:

Yes. Of course what's happened this decade is x-rays and gamma rays and through Hubble the ultraviolet; in fact, all regions. So they're all coming to the fore.

McCray:

The decadal surveys are interesting to me because I can't think of many other sciences that has committees that meet every 10 years to set the priorities. Have you participated in any of those?

Abt:

Oh, Yes.

McCray:

What are your thoughts or experiences on this?

Abt:

Well, they're needed for the funding agencies because they need some advice on how to distribute the funding. They do not want to have their group of people make these decisions. They would like to defer to a much larger group of astronomers. The attempt is to involve really hundreds of people and come to a consensus in a field rather than to depend upon a small group of administrators.

McCray:

Are they listened to?

Abt:

Oh yes.

McCray:

So they became, really, are quite essential.

Abt:

They're taken very seriously and almost all of the recommendations are funded eventually. That makes it a very dominating thing for astronomy.

McCray:

You were on the one for the 70s, the Greenstein committee.

Abt:

I guess so, Yes.

McCray:

At the Center for History of Physics they have one or two very poorly preserved audio tapes of those meetings and it's interesting. I listened to them last summer. I can hear you and Steve Strom and some various people discussing things back and forth.

Abt:

Your knowledge of that is better than my memory. I've been frankly so busy the last three decades that people have not asked me to take part in these big things.

McCray:

What are some other big trends in astronomy that you've seen? One of the things I've thought of are the relations between the military and astronomy, which I don't think tends to come out quite so much. But there are connections, I think, in the technology development. I was wondering if you had any thoughts on that aspect?

Abt:

Well, I've known in funding the military has been there all along. For instance the 60- inch telescope at Cerro Tololo, which was at one time their largest telescope, was funded by the Air Force. The Navy used to support a lot of research in astronomy and they gradually bowed out of that. So in funding they're not that active. The military has been confronted with some of the same problems we do and trying to make observations from space. And they've had a lot more money to do this than astronomers and therefore they've developed technologies which were only available to us at a later time when they're not so urgent as far as security is concerned.

They led, for instance, in the CCD development. We couldn't afford to fund industry to do that kind of development, which required many millions of dollars. But once they were doing it for the military then we could cash in on the same benefits. And of course gamma rays started with the military too. Because they're set up in the late 60s via satellites in space to monitor any above the surface nuclear explosions. And it's one way in which you can detect whether an explosion goes off is look for gamma rays. The other way, of course, is seismographically. I just heard something interesting. The head of the global seismographic organization which keeps track of earthquakes all over the world is here in Tucson.

McCray:

I didn't realize that.

Abt:

And he talked on television the other night and said that earlier this year when— oh, they can easily tell between a nuclear explosion and a earthquake. The signature is very, very clear. Perhaps having a network, they can pinpoint where it is, either one. Remember the nuclear explosion that India set off earlier this year?

McCray:

Yes.

Abt:

He said it wasn't a nuclear explosion.

McCray:

Really?

Abt:

Yes. And they reported one two days later; there was no explosion two days later.

McCray:

Interesting.

Abt:

Yes, it's interesting isn't it. So it must have all been propaganda. But anyway that's getting off the subject. The military set up Vila satellites to look for gamma ray explosions. And in a three year period, they found 16 gamma ray bursts which did not come from the earth or from the sun. And so then a paper was written on this by Klebesdel et al in which he and his colleagues consider these and try to correlate them with places in the sky. They're isotropic — from all over the sky. They tried to correlate them with the recent Supernova and found no correlation. And so that started the whole gamma ray bursters studies.

McCray:

I guess infrared astronomy probably had similar connections with development detectors for military.

Abt:

Yes. Pretty much so. It started primarily by people like Frank Low who worked in industry and worked on detectors for the infrared. And it was pushed very much by Gerard Kuiper who got Low to come to the University of Arizona. Kuiper was interested in the infrared partly because it was an opportunity, partly because he was interested in planetary astronomy things in which molecules and the molecular spectra occur in the infrared and the microwave regions. So he's the one who looked for infrared sites and tried to design telescopes. And fostered Frank Low to develop new and better infrared detectors. And so those two share a lot of the credit for it.

McCray:

In your time here over the course of your career, are there— I guess my last questions tend to be more for looking at the broader landscape. Any particular scientific controversies or discoveries that you feel are particularly important? I know you showed me yesterday your new preprint for ApJ. The fifty most important papers. Any particular thing stand out in the last 30 years as especially as noteworthy?

Abt:

No, there's too many of them. Any field of astronomy you pick there's been big discoveries and major problems. And that's why these 50 some papers are so interesting because they outline what happened in the fields.

McCray:

Any particular controversies or debates that have gone on for an extended period of time that you've been particularly personally interested in? The ones that as an editor you followed?

Abt:

No, not serious ones. As an editor I've been very fortunate because that's one of the few positions in astronomy in which the editor has a lot of leeway toward guiding how things should happen. And the funding was there to experiment with new publication techniques. So we tried all kinds of things. We tried using microfilm for a while as a compact portable way of handling the tons of journals that come out. We've realized that videos sometimes are important for showing solar phenomena or other things which change rapidly with time. So we had a video series.

McCray:

Are these some of the examples down here on your shelf?

Abt:

Yeah these are the videos which came out. People publish papers in a journal and at the same time they've come out with a video which illustrate a certain phenomena. Now all these things of course are replaced by the online journal. You can now have videos in the online journal. But there were steps needed to get the information out until we had a better way of doing things. We tried all kinds of other techniques. Some of them stayed for a long time. Some of them we said, "Well, time has run out. It's replaced by something else."

McCray:

Electronic publication?

Abt:

Yes. A big improvement and the credit for that goes mostly to Peter Boyce. He was Executive Officer of the American Astronomical Society for a number of years before Bob Milkey came. He did well, in that, but he had an interest in computing techniques. And it wasn't just a matter of taking a journal and scanning the pages and putting it on the screen because that's a dead source. In other words, you can't do anything with that. You can't put the numbers into a computer. He wanted to have the online edition in a computer readable form. And once you do that, then you can take a table out, put it in your computer, and use it. But more importantly, he developed a technique which depended upon the ADS, Astronomical Data Systems, which has been scanning all of the major astronomical journals all the way back. These are now available in a bit map foam so that in almost any reference, it can be found immediately.

Abt:

So this is a big step and very few journals are doing that yet because we have the advantage of having most of the literature now scanned and into a computer readable form online. And then, as I say, you can bring up these old references so it's a marvelous resource. People tell me they don't go to the library anymore. Anytime they want a reference, they click on an appropriate reference and it appears on the screen. You cannot make the next step because you cannot, once you find that reference you can't click on something there because there's nothing to click on.

McCray:

Right. How has that program been implemented? How was that done?

Abt:

Peter got a half million dollar grant from the NSF to develop this and he got some technical expertise on it and they did it. Now it's done for the Astrophysical Journal, for the Astronomical Journal, and for the PASP. All three journals are now published by the University of Chicago press because they do such a good job. They're very conscientious, excellent quality, and economically good. So that the astronomical journals are getting to be in good shape. They are the envy of other fields. Other journals are now asking Peter for advice on how to do that. There are a lot of journals that are online, but they're just a bit maps.

McCray:

During the time that you've been working with the journal, you've also been able to continue your own work as well?

Abt:

Yes, on weekends.

McCray:

On weekends, okay. Do you ever wish that you hadn't gotten so involved with editing the Astrophysical Journal and had been—

Abt:

Well, it depends on what you want to do with your life. You develop a conscience. Most of us develop a conscience. We've been given good equipment that we use for all our research and we feel as though we should pay back something. You can either do that by teaching students because people spend a lot of effort teaching you. You can do other things for astronomy and this happened to be one in which I thought this is really worth while doing. And also, if there's enough freedom that we can experiment and do something new. So no I don't regret spending a lot of time on the Astrophysical Journal. And I've managed to get a lot of research done.

McCray:

Has your research stayed pretty much on the same trajectory that it was before you took over with stellar classification and binary stars?

Abt:

Probably so and I think that the biggest weakness of my research is that I haven't spread out to different techniques. For instance, classification is still done visually by photographic plates. Well, that's not how we get spectra anymore. We get CCD scans. And so now, once I'm free of the journal, I want to explore techniques for using CCD scans for classification. It's been done by a couple of other people but of course each person has to do it for himself. I'll use the best of their ideas. No, I haven't broadened research techniques and haven't even kept up on the literature which is terribly hard to do.

McCray:

I'm staring at 40 square feet of it, it looks like here at least.

Abt:

I figured out once that if you read all of the Astrophysical Journal at the rate of five minutes per page, you'd take 250 days a year to read it. That doesn't leave much time, so we all specialize. And now it's just a matter of following just certain narrow specialties and depending on search techniques to find papers we missed.

McCray:

Any final thoughts on the bigger picture of astronomy and how it's changed? You came in at a particularly golden age. You were the first student to graduate from Caltech and participated in getting Kitt Peak off the ground. And then came to Kitt Peak when it was new and then have served as an editor here for almost 30 years. What does the big picture look like to you?

Abt:

I'm continually impressed with how many things we can discover. Almost anything you work on ends up with surprises, things which we have not been clever enough to predict. So that happens at all levels. And so perusing research leads to a lot more research and each problem you do it maybe answers one question but it brings up another dozen questions that you see need to be answered. So there's a endless amount of things that still need to be done. We're not running out. We're not like the patent office which was about to close in the 1890s.

McCray:

How has the community changed? I know it's gotten bigger and the new technologies and new wave lengths and things like that. But when you to a AAS meeting, do you see any demographic shifts that are particularly important?

Abt:

Yes, a lot more young people. I have told people that you can tell when you've reached middle age in astronomy because then more people recognize you than you recognize them. So yes it's full of young people. I've corresponded with most of them, but I haven't met them face to face. It's fun to go to a meeting and meet the people that you've been corresponding with for a long time. There's a huge amount of new stuff coming out. Occasionally you can say, "Well this isn't very important but I'm glad they're doing it." But there's a lot of big surprises each time, more than we can absorb. It's still a fun field.

McCray:

You're still having fun?

Abt:

Oh sure.

McCray:

Well, that's good. I think there aren't many people who can look back and say that after they've doing something for a long time. That's good. I'm out of questions and topics. Are there any important topics that I've neglected that you would like to touch upon?

Abt:

It depends on what you're after. Philosophical view points of the field or details about my own research or me as a person or what?

McCray:

Well, all three would be fine. We've got some time on the tape left. How about the personal aspects? Other than astronomy what else do you do?

Abt:

Okay. I've never been married so that's allowed me to work long hours and seven days a week and lots of freedom for that. Somewhere along the line I've picked up a person who I called a son, a person who was thrown out by his family and I took over his responsibilities. He's the one who's been calling me occasionally as he does, and it does take a lot of time. I had facilities to help him and he's fine. He's independent now more or less. I've always maintained a lot of other interests besides astronomy. One is a strong interest in music.

McCray:

I noticed records in your office. You're one of the few people who still has a turntable, in their office especially.

Abt:

Yes, plus tapes and CDs and everything else you can think of.

McCray:

I noticed also Japanese music.

Abt:

Yes, a lot of oriental music. Chinese. I've been to the Far East a number of times. A long time ago I felt very attracted to Japanese culture because they have a strong sense for beauty which I also have. So almost everything they do they like to do in a beautiful way. You go to a Japanese meal and it looks good besides being tasty. But I like their literature, their prose, their poetry. Their music I like very much, surprisingly, because at first it sounds offensive to us. Then I went to China a number of times and like them very much too. Developed friendships with people in China. I got a strong interest in jade, so you can see jade all around us.

McCray:

Yes, I noticed many jade carvings. Where did your bonsai tree come from?

Abt:

Oh that came Florida. It's about 10 years old. I've had it for three or four years. I like bonsai trees. And I like to travel. In fact in the 1940s and 1950s, I spent a lot of time in Northern Arizona and Southern Utah. First on these organized exploration trips with Bill Miller and then just exploring the region. I had a jeep and there's some wonderful country up there which is fun to explore. Then I got interested in Pacific Islands and I spent a lot of time on vacations going to Pacific Islands. Partly because they're so beautiful and partly they have interesting places like Easter Island and Galapagos. And I spent a lot of time in Fiji and Hawaii, of course.

McCray:

Any particular activities that you like while you were there? Bird watching or natural history?

Abt:

Snorkel swimming, hiking, flaking out in the sun, whatever. So that was fun and I haven't done that in recent years. All the countries, you know, Australia, New Zealand, Japan, Indonesia, you name it. Then I started going to Europe occasionally and that's interesting for the cultural interests so I've been to a number of European countries and soaked up things. The wonderful music in France and wonderful museums and things like that. And then in the recent decade or two, I've been going to the Far East. China, Thailand, Korea and Japan.

McCray:

I noticed your CV has, there's a reference to a Chinese award.

Abt:

Oh the prize.

McCray:

Yes. What was that about? Can you tell me the name of it first of all because I can't seem to find it here?

Abt:

Y.C. Cheng Prize. Well, the Chinese astronomers have had a rough going. Astronomy was almost dead during the cultural revolution of course. Just since about 1980 that they have built up expertise in there. They're developing very quickly. But of course they don't have much money, particularly individuals. Even now almost all Chinese astronomers gets the same wage which is about S2,500 a year. They have no prizes and of course that's part of the Oriental tradition of not making people outstanding individually. That's true of our Native Americans too. We are very strong in this and try to recognize quality. Which system is better, I don't know. But I thought I'd start a prize in China which involves giving $1,000 to a person who has done outstanding research in the past five years.

McCray:

This is the Y. C. Cheng Award?

Abt:

Yes.

McCray:

Who is Y. C. Cheng?

Abt:

He was a long time director of the Purple Mountain Observatory.

McCray:

Which is?

Abt:

In Nanjing. Their oldest and one of their best observatories. I happen to know him because he got his Ph.D. at the University of Chicago back under Van Beesbrook about 1930, worked for Otto Struve. Then he went back at a difficult time and he had a very difficult career. But I did meet him in 1985 and a wonderful, gentle, nice person.

McCray:

When was this prize established?

Abt:

Early '90s. It didn't seem good to have a prize like that funded by an outsider. I mean an American so that's why we named it for what was then their most outstanding astronomer, recent astronomer.

McCray:

What are the facilities like for astronomy in China?

Abt:

Growing very rapidly. And Chinese work terribly hard, extremely hard as students and later on. Now their largest telescope is about a two meter telescope and they're planning bigger equipment. So equipment wise, it's still far behind.

McCray:

How about site or the locations for possible telescopes?

Abt:

Fairly good, none of the quality of Hawaii or Chile. An interesting thing that happened to us is that there's a astronomer by the name of Kam Leung at the University of Nebraska who was born and raised in Hong Kong, knows Cantonese, and is a specialist on eclipsing binaries. Starting about 1980 after China opened up he started going to China every year. And he fostered the people who wanted to do observational astronomy.

They had small telescopes, but nothing large. So he showed them how to build a electric photometer, told them what stars to observe, how to do the reductions, and helped them with the interpretation and publication of papers. So he got them started in this. And then after five years he said I think you're ready for an international meeting, so he organized one in 1985 in Beijing. And there was a dozen or so people from the United States who went there, I happen to be one of them. And we had a very nice international meeting. Before that occurred, he started going to South Korea and getting them started with observing eclipsing binaries with their small telescopes.

And after five years he said, "Well, I think you're ready for an international meeting." So there was an international meeting in 1990 in South Korea, which some of the same people went over there who are interested in double stars and binaries, and had a nice meeting. Before that happened he started going in Thailand and doing the same thing. So in 1995, we went to Thailand for a meeting. It happened to be just when there was a solar eclipse there. Then the next one was in Hong Kong. He didn't have to— Well, he's been pushing them too. Their work was mostly theoretical. They don't have much equipment, but they do superb work on dense stars such as white dwarfs and neutron stars and other such exotic things. He's a one man organizer. He'd been doing all this himself.

The more recent ones he's helped organized, but he's getting more help now from other people. And we had another meeting there this past summer in Hong Kong, again very successful. Much less emphasis on eclipsing binaries, more on dense matter and neutron stars and such exotic things. And they've become called Pacific Rim Conferences. So there have been five of them now and now we're looking forward to the one in 2002 probably to be held in China and probably in Xi'en, the old capital.

McCray:

So with the Pacific Rim Countries, do you see them as going to eventually become a fairly powerful intellectual force?

Abt:

Yes, because those people are terribly energetic. They have this tradition of fostering culture or fostering knowledge and they push their young people hard and some of them turn out to be exceedingly good. So Japan, China, India, South Korea, these are all pushing point forward. Hong Kong.

McCray:

I can't recall who it was, it was somebody and I mentioned that I would be interviewing you in the fall and they said I should ask you about cars.

Abt:

Cars?

McCray:

Yes, they said you were interested in Corvettes.

Abt:

I had Corvettes for a large number of years just because I thought it was a very beautiful car. Now I drive a conventional Pontiac. The Corvettes are really the only cars I particularly cared for. Yes, I was this young bachelor zooming around in his yellow Corvette so it presents a certain picture, which was not completely characteristic.

McCray:

So you mentioned a philosophical view. What is the aspect of your life, your work that makes you the happiest? That's been the biggest reward for you?

Abt:

Everything. I like all the things I do. It's been a wonderful existence. I like my work so much so that I spend seven days a week at it. I like to read a lot and I read quite a few books. I like music very much. I'm involved with the local chamber music organization.

McCray:

Do you play yourself?

Abt:

No. The organization produces chamber music concerts. We bring the best musicians in the world here. And the bags you see sitting over there.

McCray:

Oh, yes.

Abt:

Plus early in the year, we started commissioning new pieces so we put out an advertisement and 114 composers sent in applications. And it's full of packets in which composers sent their CVs and tapes or cassettes or CDs of their compositions. And three of us in this organization have been sifting through all of that. There's a huge amount to listen to there and we've now picked five people. Which in the next coming five years we will commission a work for each one. What you see there is 109 people that we're turning down, and I'm going to write a letter to each one.

McCray:

That's always a difficult task to do.

Abt:

Yes, but it's a wonderful group. They give seven or eight concerts every year. The best quartets and best trios and so on. And they started a piano series so we have three concerts every year of young pianists, the ones who are just emerging. And then we started a winter chamber music festival which is in it's sixth year. It's held in March. It's the only one in the country in the winter time. A week of intensive chamber music, which we bring again the best musicians we can find. Then we foster concerts in the public schools. We give free tickets to students to come to our concerts. Now we're starting a commissioning series.

McCray:

Do you have any particular composers that you like?

Abt:

Personally? Sure. Mahler, Brahms, Ravel.

McCray:

What an interesting mix.

Abt:

Oh, and very strong on contemporary music.

McCray:

I wouldn't have pictured that.

Abt:

Continually exploring contemporary music. You know, George Crumb and Lou Harrison, John Cage, you name them. All the serious ones. I've always liked contemporary music and it's fun to hear what's coming out. A lot of them are duds and then you find other ones that are interesting.

McCray:

Do you have a favorite instrument?

Abt:

No, not particularly.

McCray:

Well, I can't think of any other questions and I probably should close so I can be sure to catch my flight in time. Once again, thank you very much. I really appreciate it.

Abt:

Well, I'm impressed with how well prepared you've been.

McCray:

Oh, thank you.