Oral History Transcript — Dr. Eugene H. Avrett
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Eugene Avrett; October 14, 2005
ABSTRACT: Dr. Eugene Avrett (1933 - ) is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. This interview reviews his personal and professional life and was conducted as part of a study of the history of the SAO during the tenure of Fred Whipple, 1955-1972. The interview covers his family life in a suburb of Atlanta, Georgia, public schooling and development of interests, influential teachers, and matriculation at Georgia Tech in electrical engineering in 1952. Facility in conceptual subjects like physics, but no special interests. Knowledge of WWII. Summer employment at Glenn L. Martin Aircraft on Matador program. Decision to switch to physics. Graduation in 1957 and entrance to Harvard for graduate study in physics. Advisors included Gerald Holton, Max Krook, George Carrier. Growth of interest in astrophysics slow, due to Krook and exposure to, first research in, and publications in stellar atmospheres. Teaching assistant for Bill Liller. Thesis with Max Krook. Collaboration with Owen Gingerich. Marriage in 1961 to Judith Reno Brett. Ph.D. in 1962, conferences attended that solidified his interests in stellar atmospheres and spectral line formation and non-LTE processes. Hired by Charles Whitney into the ďStellar Theory DivisionĒ at SAO. Organization of SAO under Whipple and his managers, including Harris Rosenthal, Charles Lundquist and Paul Tillinghast. Impressions of joint program between Harvard and Smithsonian. Teaching activities. Backup theoretical group for Celescope; extended discussion of Celescope, calibration issues, and the challenge of analyzing the data and the production of the catalogue of UV stellar colors. Nature of the data, methods of post-hoc calibration of the fields. Continued refinement of stellar atmospheres techniques and changing state of knowledge of theoretical energy distributions mitigate value of Celescope data. Role of Celescope staff, mainly Robert Davis, in the processing. History of OAO program; failed launches. Nancy Romanís role in OAO and suggestion to close down Celescope. Work with student Steve Strom to prepare for Celescope reductions. NASA conference on OAO results. Relations between HCO and SAO and between Leon Goldberg and Fred Whipple. Teaching and thesis direction by SAO staff. Strom and early development of optical astronomy at SAO -- the MMT. SAO collaboration with Arizona rather than with Harvard. Use of OSO data for solar atmospheres research. Layoffs at SAO, deteriorating relations between Harvard and SAO and the formation of the Center for Astrophysics.
DeVorkin:This is a taped recorded oral history with Eugene Avrett in his office in the Perkin Building at the Harvard-Smithsonian Center for Astrophysics. The Interviewer is David DeVorkin. The date is 14 October 2005. Auspices are the AIP, Smithsonian Institution, and the National Science Foundation. You were born on October 28th, 1933, in Atlanta, Georgia. Please give me a brief overview of your family background.
Avrett:Iím one of three sons, the youngest, and I grew up with my mother and father and brothers in a suburb of Atlanta, Druid Hills. The house was right across the street from the campus of Emory University. I went to Druid Hills High School, which was a very good public high school at that time. In my last year of high school, I wrote away for the MIT catalog, thinking that would be a nice place to go. But when I saw the tuition, I didnít even discuss it with my mother and father. I just thought that was too much money to pay for college.
DeVorkin:Thatís pretty important, but letís back up and figure out how you got there. Your dadís name, his background, and then your mom?
Avrett:My fatherís name was Robert Cary Avrett, and my motherís was Annie Berry Hinton. My father was manager and vice president of a commercial feed mill for animal feed. It was the Alco Feed Mill.
Avrett:Very little college. Just a business course, but no real college. He valued education and he was happy that his sons were educated. My oldest brother went into the Marines right after high school in World War II and came back and did not want to go to college. He went into business and was successful in insurance and real estate.
DeVorkin:Whatís his full name?
Avrett:Robert Cary Avrett, Jr. The middle brother, John Glenn Avrett, went to the University of Georgia in Journalism, and then to New York City in the advertising business. He was very successful and ended up owning his own advertising agency in New York City.
DeVorkin:What was the family financial status during the Ď30s, as you were growing up?
Avrett:My father evidently had stable employment in his position with the Alco Feed Mill. I was born in í33, and we moved to a larger house across from Emory University in 1936. It was a former fraternity house.
DeVorkin:That sounds like a big house.
Avrett:Well, no, it was four rooms over four, but a large house, and it was in terrible condition. He bought it for very little money. I remember he was earning $600 a month, which was regarded as a very handsome salary at that point, so we really didnít have any money worries.
DeVorkin:You went to Druid Hills High School. What about your elementary schooling?
Avrett:That was at Druid Hills Elementary School. Everything was just the local public school.
DeVorkin:And they were all public schools?
DeVorkin:How would you recall your family life? Were there a lot of books around, did your parents subscribe to magazines? Did you listen to the radio or do a lot of family things?
Avrett:There was not a lot of reading, but there were newspapers and magazines. Every week I would read the news magazines, so I had an interest at an early stage in what was going on in politics. I never really read much literature or history. In high school, I began to notice that I was better in science classes than anything else, and gravitated toward engineering. I started Georgia Tech in electrical engineering. The school system, elementary and high school, was quite good. It was not the most affluent suburban area of Atlanta; that would be Buckhead at that time. It was maybe the next best in the Emory University area; the students were all motivated and the teachers were good; thatís just the way suburban school systems should be.
DeVorkin:What about your interests? Did you have hobbies?
Avrett:Not really. I was sort of a late bloomer. I didnít do well in elementary school. In fact, I spent two years in the fourth grade because I was not paying attention. They thought if I were a little bit older, that would help; and maybe it did, I donít know. So after that point, I was always just a year older than my classmates, which didnít make that much difference. I really picked up academically in the middle of high school or maybe the second year of high school, and just started paying attention to all my classes. I even learned how to write reasonably well in one class. I had one inspired teacher that made us write essays.
DeVorkin:Thatís the key. Iím looking for what made that difference.
Avrett:There was one inspired teacher who made us write essays about ourselves and so that was an interesting subject! I never saved any of them.
DeVorkin:What was the teacherís name?
Avrett:Mrs. Huey, she was the mother of one of my classmates, and probably more well-educated and intelligent than many of the other teachers. Because she had a son in the school, she was maybe motivated to participate.
DeVorkin:So was this a watershed for you?
Avrett:It opened me up a little toward careful writing. That was my experience in writing skills. I suddenly found myself comfortable, labored always, but comfortable, and I would work over things until I felt they were right.
DeVorkin:Were there any math or science teachers that you remember?
Avrett:The teachers were good and I had no complaints. There wasnít great inspiration, but I found I was interested in the subject. All my questions were answered and I knew what was going on. I never felt very strongly in favor of biology, but the physical sciences and math appealed to me very much. I like conceptual subjects where you donít have to remember a lot of details. You can just derive everything from first principles whenever you need it, and thatís very nice.
DeVorkin:If you can do that, thatís great. Thatís a real difference.
Avrett:So thatís one thing I like about physics better than chemistry. With physics, all you need to know is the general ideas and you can derive anything you wish. With chemistry you have to remember a lot of details. Iím comfortable with physical intuition, and I visualize how things work and I can put it all together.
DeVorkin:You were seven or eight when we went actively to war. When were you first aware of World War II or of the European War?
Avrett:I was aware of it. I had a map on my bedroom wall of Germany, and I was tracking the front lines as they converged. I remember following the week-to-week progression of the forces during the end of the European War.
DeVorkin:What prompted you to do that?
Avrett:I donít know. It was in the news.
DeVorkin:Did anybody else do that that you know of?
DeVorkin:Was this something that your parents found interesting?
DeVorkin:Just completely on your own. Well, was this after your brother went?
Avrett:He was in the Pacific, actually. In fact, I was less interested in the Pacific War because that was just island-hopping and all this. But the converging front lines in Germany, that was sort of a nice graphic to track.
DeVorkin:Did you give any reports on it in high school?
Avrett:No. It wasnít prompted by anything. In fact, all I remember is that map on my wall, and I kept drawing lines.
DeVorkin:Did you do other things like that?
DeVorkin:And by the time you were in high school at that level — no, you would have been nine, ten years old, right?
DeVorkin:So you were quite young. Had you developed any hobbies?
Avrett:Well, I did some basement experiments. Not experiments as such. I understood internal combustion principles and forces and pistons moving and I thought, ďOh, I can construct one of these things out of just materials at hand.Ē It was just ridiculous, because I didnít have the tools, I didnít have the equipment. I didnít have anything!
DeVorkin:Yes, that would be quite impressive if you could do that. Was your dad a tinkerer at all?
Avrett:No, he didnít have any background in any of this; it never occurred to me to discuss science issues with him.
DeVorkin:So he wasnít an amateur astronomer or anything?
DeVorkin:Did he have hobbies?
Avrett:Not really. He was a quiet businessman. He would come home from the office and sit in his big leather chair and listen to the radio news and read his paper, and that was about it.
DeVorkin:How about your mom? Did she have any hobbies?
Avrett:She was more active and attentive to her children, I suppose, maybe a bit overbearing in some ways. She trained herself to be a schoolteacher.
DeVorkin:She trained herself? Did she go to college?
Avrett:One important thing is that when we moved into this house in Druid Hills, I donít know whether it was because money was tight or she just wanted something to do, but she opened a kindergarten in our house. The whole first floor of our house was devoid of furniture because it was an open space for the kids to run around in kindergarten. I think we had a dining room table, but the living room was open, no rugs. She ran the kindergarten probably five years, six years.
DeVorkin:Was it a kindergarten or what youíd call daycare now, or a real kindergarten?
Avrett:There wasnít any classroom instruction, but it was projects and the kind of play games that have some instructional value. I think there were about 20 kids, and it was the kindergarten or nursery school. I think she called it a nursery school.
DeVorkin:Thatís very interesting. Did she go and get formal training for this?
Avrett:I donít think she had any training at all. Her mother was a schoolteacher, and maybe she picked up some of that. In later years, maybe when I was in collegeÖI donít know when it was, or maybe it was just some years after her kindergarten experience, she took some evening courses and got a teaching degree. She had been to college somewhere; Iíve forgotten where. She had a four-year college degree, but got a teaching degree part time and then began teaching first grade when her three sons were away.
DeVorkin:What was her influence on your life?
Avrett:She didnít have any strong academic influences. Whether I would do homework or not homework that was up to me; she didnít really press me on this. Maybe that was one reason why I goofed off until finally I realized that I had to make my way in the world.
DeVorkin:Yes, what happened when you had to repeat fourth grade? Do you recall your parents worrying?
Avrett:No, I think it was just a recommendation of the teachers that I didnít seem to be paying much attention and might be better off doing this again.
DeVorkin:Nothing deeper than that?
DeVorkin:Okay. To situate you then, through the war, there must have been tension with your brother in the Pacific, but beyond that, you proceeded through school relatively normally?
DeVorkin:You gave that wonderful little story at the beginning about how you looked up what it would cost to go to MIT. Where did the idea of going to college first emerge?
Avrett:I didnít even give it any thought until the fall of my last year of high school, and then I wrote away for the MIT catalog just because I thought I did want to go to an engineering school and MIT had the reputation as being one of the best.
DeVorkin:There were no school counselors or teachers who suggested it?
DeVorkin:Did your dad suggest it?
DeVorkin:You were completely on your own?
Avrett:It was just on my own, yes.
DeVorkin:Okay, and then you found out how much it would cost.
Avrett:I just thought I didnít want to ask my parents to support anything like that, because the alternative was to be a day student at Georgia Tech at a cost of $60 per term.
DeVorkin:Yes, and that is a technical school.
Avrett:Yes, and it was a pretty good school.
DeVorkin:Yes. But you were looking at the best or what you thought was the best at that time. Did you consider or did anybody advise about scholarships or anything like that?
Avrett:I was making straight Aís in my last year of high school and a B+ the year before, but it wasnít a really distinguished record all the way through.
DeVorkin:It was improving constantly?
Avrett:It was constantly improving.
DeVorkin:You said you made straight Aís your senior year?
Avrett:I think so, yes. And then at Georgia Tech, I made almost straight Aís. But now, one thing that I look back on with some regret is that, just due to maybe a feeling of insecurity or just making sure than I had a good academic record, my objective was to make straight Aís. I would play games with myself and study for a test in order to be able to answer every question, but then I would immediately forget because what difference did it make then because a grade wasnít involved. In other words, I wasnít approaching this from the point of view, ďI really want to learn this material cold.Ē I was approaching with this, ďI really want to ace the exam,Ē and thatís a difference. I remember finishing the first year of calculus straight Aís, and the second year of calculus, after a summer, I couldnít remember anything.
DeVorkin:You knew how to study for an exam. Did you learn that from anyone or did you just figure it out?
Avrett:No, I just figured it out. I would do various things that were most adaptable to my own situation to be able to do that. I remember a senior class I took in electricity and magnetism. The professor told the class that one of the questions he would ask is — and heís giving this to us in advance — to write an overall summary of the structure and development of the subject of electricity and magnetism, you know, three pages or something like that, just giving the derivation and everything. I really worked on that. What I then sat down and wrote during the exam, he showed around to all the professors and said, ďThis is really remarkable. This is a better summary than IĎve ever seen.Ē I think Iíve saved that.
DeVorkin:How did that make you feel?
Avrett:It made me feel very good. Very good. Yes.
DeVorkin:Were you consciously choosing your career at this point, or still exploring?
Avrett:When I started Georgia Tech, I had to choose a major. I chose electrical engineering, not just for any urgent reason; I just thought it seemed attractive. I also immediately joined the cooperative ďco-opĒ program. Georgia Tech was a four-quarter system; fall, winter, spring, summer, so it was a full summer session, just like the other three. I started in the fall, and this was in a work-study program. Fall and spring I would be in school; winter and summer I would be working. They sent me to Baltimore, to the Glenn L. Martin Aircraft Factory, which was a very good program, taking the students and putting them in one department after the other, all the way through, starting in manufacturing and working [through] inspection and engineering and quality control.
DeVorkin:So this is between í53 and í57, before í57?
Avrett:Yes, I started college in í52 and finished in í57, so it was five years.
DeVorkin:Yes, this indicates that you got your degree in í57.
Avrett:Right. But this was very informative. I really saw the whole manufacturing process.
DeVorkin:But this was purely aircraft?
Avrett:Yes, it was building aircraft.
DeVorkin:They were building rockets at that time, too.
Avrett:Yes. They had a rocket that would take off like an airplane — The Matador.
DeVorkin:Yes, but they also were building the Viking. I donít know if you know that name, but itís what became Vanguard. Did you see any of that going on?
Avrett:Well, I worked on the Matador. I wired up a few of them.
DeVorkin:You were going around from office to office, so you didnít have a particular boss.
Avrett:No, Iíd spend the whole three months in one department. The first time I was just in manufacturing, but they would move me around several different places. The managers treated us as just some additional help that they would put doing the most tedious work that nobody else would want to do, like a big stamping press that you put a piece of metal and you push down, go crash.
DeVorkin:Did you know what you were working on?
Avrett:Those were just little pieces that would go into aircraft or missiles or something.
DeVorkin:Did you know what the product would be? I mean, did you see a completed Matador, for instance?
Avrett:Oh, yes. Later, I was put on a Matador assembly line as one of the team that were actually pulling wires through and fastening things like this.
DeVorkin:What was that sort of work like for you? What did you think of it?
Avrett:The first term in manufacturing was just terribly boring. Iíve had summer jobs before, but this was the most tedious. I remember the first day, after an hour or two I realized that I have to do this for eight hours before I can leave! But then realizing that most of the working population does that, I had to get used to it.
DeVorkin:So your idea was that you were part of the working population?
Avrett:Right. But then, three years later, I was in engineering, and I was given an assignment, ďHereís all the blueprints for this aircraft, and we have to mount this instrument at this place in the wing, and go to it. Give us the plan of where to cut and what to do and where to place it and so forth.Ē So it was just a little bit of spatial stuff and design work, and I didnít do it very well. Then I was in the electrical testing and did all that. The whole experience finally convinced me I did not want to be an engineer, so I didnít quite finish the program, and I switched to physics. That, at that time, had appealed much more to me. I did very well and I was the top student in the physics department at that point. In fact, because I was on a five-year program and I dropped out before the last term or two, I was ahead of myself in courses. I couldnít have quite done it in four years, but the five years allowed me time to do other things; so, the Physics Department invited me to teach one section of their introductory physics courses.
DeVorkin:When you were a senior?
Avrett:Yes, so in senior year, I taught the fall term and the spring term.
DeVorkin:Was that a source of income, as well?
DeVorkin:Was the income important?
Avrett:Yes, I think so. I was still living at home and my expenses were not great, but I think that helped.
DeVorkin:Youíre a senior. You switch to physics; youíre doing very well in physics. Whoíd you talk to about what youíre going to do afterwards?
Avrett:Nobody, really. I canít remember ever getting much counseling from anybody.
DeVorkin:Your family, your brother?
Avrett:I did a very risky thing: I applied to Harvard and to Princeton, and thatís it.
DeVorkin:Were those the only two?
Avrett:Right. I got turned down by Princeton and I was accepted at Harvard.
DeVorkin:Thatís interesting. It usually goes the other way around. But you got to Harvard, and thatís physics?
Avrett:Even though I didnít have any money, I was not offered any financial aid.
DeVorkin:Now, this is í57, right?
Avrett:í57, right. So I came here at the beginning of the summer and took some courses in summer school. I donít know; I just wanted to get started. I borrowed money from my two brothers and my mother.
DeVorkin:But not from your dad?
Avrett:No, my dad had died at that point. No, wait a minute. He was ill and he died the fall after I came.
DeVorkin:Fall of í57?
Avrett:Yes, so money from my mother and father.
DeVorkin:We had finished talking about the Glenn Martin Factory and your decision to switch to physics.
Avrett:I then taught introductory physics courses in my senior year.
DeVorkin:And you got loans from your family and that places you now in Cambridge.
Avrett:I got $300 a month from my two brothers and my mother and father.
DeVorkin:Was it open-ended?
Avrett:I said until I can get a job. So I was here during summer school, and then I was able to get a teaching fellowship in the fall.
DeVorkin:That had not been arranged prior?
Avrett:No, I managed to make those arrangements. I was teaching half time, and that supported me fully.
DeVorkin:Was this teaching undergraduates at MIT half the time?
Avrett:No, this was being a teaching assistant in undergraduate courses at Harvard. In fact, I think one of my first jobs was a teaching fellow in applied mathematics, and also there was a teaching fellow in astronomy working with Bill Liller.
DeVorkin:Oh, really? Now, you were assigned that at random?
Avrett:Well, I was just trying to find a teaching job for my own support, so I would go around and ask whether they needed anybody.
DeVorkin:So you came all the way up here to the observatory?
Avrett:It was a course that was given in the Yard. Maybe that was a bit later that I did Lillerís Astronomy I, but I think in the early days I was just grading papers for undergraduate math courses.
DeVorkin:That was a half-time job?
DeVorkin:Who was your advisor in the Physics Department, and what were your plans?
Avrett:My nominal faculty advisor that I would see just once a term to approve courses was Gerald Holton.
DeVorkin:And he was in the Physics Department?
Avrett:Yes. Still is, I think.
DeVorkin:He had a dual appointment. So you had him as an advisor?
Avrett:Yes. I never really talked to him about history of science.
DeVorkin:You never did? So that wasnít something that he was myopic about? He was strictly talking about physics?
Avrett:He didnít really talk to me about physics either. It was just a nominal responsibility that he was carrying out for the department to just sign my course grades, and so I didnít have any contact with him, really.
DeVorkin:So he wasnít in the position of advising you in the career sort of sense?
DeVorkin:Was there anyone?
Avrett:Nobody else either. The graduate students talk a lot among themselves, and we get to know what the opportunities are. Now, most of the graduate students in the Physics Department at that time were lining up once a week to have a brief appointment with Julian Schwinger and he was the advisor to most of them. I didnít want to have anything to do with that.
Avrett:It was too competitive. I looked around a little bit further. I got to know George Carrier and Max Krook, and Max Krook ended up being my advisor. My second research paper was Carrier and Avrett on a solution of a little problem in applied mathematics. My thesis topic with Max Krook was a topic of interest in stellar atmospheres of trying to determine, subject to the energy constraint of rate of equilibrium, what the temperature distribution would be. Everyone at that time was still doing it by trial and error, and we worked out a systematic mathematical scheme for this that was referred to as the Avrett-Krook Method for determining the temperature distribution of stellar atmospheres. There were two papers published in the Astrophysical JournalÖ
DeVorkin:And that is Astrophysical Journal, Volume 137, Page 874, 1963. Thatís Avrett and Krook. The two papers prior, you already mentioned, Carrier and Avrett, ďNon-Gray Radiative-Transfer Problem.Ē [Carrier and Avrett, A Non-Gray Radiative Transfer Problem, Astrophysical Journal, Volume 134, p. 469] That, of course, applies directly to Astrophysics as well. The next one is Avrett only, ďParticle Motion in the Equatorial Plane of the Dipole Magnetic FieldĒ [Avrett, Particle Motion in the Equatorial Plane of the Dipole Magnetic Field, Journal of Geophysical Research, Volume 67, p. 53]Ö
Avrett:Thatís something I just did completely on my own. I was a teaching fellow in an electricity and magnetism course, and it occurred to me that I could solve analytically a problem that most people were solving numerically. In a dipole magnetic field, and it looks like the Earthís magnetic field, a charged particle will move in a circle around the magnetic field line, but if it has also some motion northward, say, it will spiral toward the north pole, and then because of the converging magnetic field and other forces, it will spiral back and forth as it goes around. I worked out a nice little analytic solution of that and sent it off to the Journal of Geophysical Research, and it was published.
DeVorkin:So, youíre going through a physics degree, which makes you pretty much competitive for a lot of other fields. Would you say that there was any specific interest in astronomy at this point?
Avrett:No. I had never had any amateur interest in astronomy, although from a physics point of view, I was interested in planetary motion and eclipses and things like that.
DeVorkin:Didnít Sputnik excite you, or Moonwatch? Were you aware of those things?
Avrett:I remember the fall term of my first year as a graduate student was í57. When Sputnik went up, and I was very impressed, just from a general point of view, because I had been following the program that this country had prepared for the IGY. I knew all about satellites and things, and so there was no surprise to me about launching something into orbit. That was elementary physics. But politically and historically, the way our country was engaging in all of this, I found this very interesting.
DeVorkin:Any activities on your part equivalent to the World War II mapping project that you had?
DeVorkin:Keeping track of the satellites or anything like that?
Avrett:I read everything that was available, but I didnít really get deeply involved in it.
DeVorkin:At what level did you read? Did you read Sky and Telescope by that time?
Avrett:No, I hadnít encountered Sky and Telescope.
DeVorkin:Did you know about the Smithsonian Astrophysical Observatory Contributions?
Avrett:I wasnít aware of that at that time.
DeVorkin:Okay, so you were wholly within physics; you were aware of it at a man-on-the-street level, basically.
Avrett:Yes. Maybe it was two years after í57 that I first started working with Max Krook. I was aware that he had an association with SAO and was getting involved in satellite trackingóthat they needed people to solve some of these mathematical problems and that he was sort of peripherally drawn into some of this. So I was aware of this activity through him.
DeVorkin:How did you and he meet or how did you become his student?
Avrett:I was just shopping around for a project to work on and approached him and said, ďDo you have any ideas?Ē And he said, ďYes, try this one.Ē
DeVorkin:And you werenít thinking of stellar atmospheres?
Avrett:No, it could have been anything. It could have been some other field of applied mathematics. I approached it from the point of view of applied mathematics and I later learned how it was being used in astrophysics.
DeVorkin:I take it that the contact you had, reading for Liller, didnít have any influence on you?
Avrett:No, I just learned some elementary astronomy then.
DeVorkin:All right, so through 1964, at least with the beginnings of your studies of the departures from local thermodynamic equilibrium [LTE], I see youíre beginning to collaborate with other people up here: Wolfgang Kalkofen, Steve Strom. A lot with Steve Strom, actually.
Avrett:Steve Strom was my thesis student.
DeVorkin:He was your student?
DeVorkin:Well then, somewhere in here you must have a thesis?
Avrett:My thesis was with Max Krook.
DeVorkin:And that was the temperature distribution of the stellar atmosphere?
Avrett:Actually, there were two papers there and the Carrier papers were bound together with a long introduction, and that was my thesis.
DeVorkin:Thatís pretty good. Is that pretty standard for Harvard, do one or two publishable papers with an introduction?
Avrett:Sometimes, if theyíve actually been refereed and published and you write a nice introduction and you can convince people to go along with that.
DeVorkin:I suppose you still have to defend it. Iíve heard in some places that if you ended up publishing something, you canít use it as your thesis. Do you know about that?
Avrett:It doesnít work that way here.
DeVorkin:I take it you would prefer the way it is?
Avrett:Yes, because I put a lot of effort into those particular research projects. I wanted to continue, but I didnít want to set back and write a little monograph in the subject, which would be the alternative.
DeVorkin:Yes. Was Carrier was in the physics department?
Avrett:No, he was in applied mathematics; it was the Division of Engineering and Applied Physics, and basically he was an applied mathematician in the division of applied physics.
DeVorkin:Is there some point along this line, though, where you made the choice to do this work in stellar atmospheres, and you realized that you are moving into astronomy?
Avrett:Once I started writing these papers with Max Krook, I also became involved with Owen Gingerich at that time; that fits in a little bit with his career. Gingerich was writing a thesis at that time based on a computer program to simulate the solar spectrum, but he needed this mathematical method that I was developing with Krook in his program. As I was deriving all this, I would get him to try out various things, and when they worked very well, I was more encouraged than when they didnít work very well. So he helped me test out some ideas, actually.
DeVorkin:So you wrote the theory, he applied it, programmed it.
Avrett:Right. So he finished his thesis based on his program, and I finished my thesis based on the method that he used in his program.
DeVorkin:Right. Did he engage at all with you in developing the method, the theory?
DeVorkin:Not at all?
Avrett:I just gave him the equation and said program this.
DeVorkin:And thatís what he was good at?
Avrett:Right...He was a very good programmer at that time.
DeVorkin:Yes. I am learning some of the other ways that he got into history. Of course, Iíll be talking to him extensively.
Avrett:Yes...I remember at that time he was dividing his time between this computer work of simulating the solar atmosphere and writing a little program to be able to translate Latin, because he was, even then, reading these texts, and he didnít know Latin to begin with. He would translate word by word and kept studying and he produced his own little dictionary.
DeVorkin:Yes, I know a little of that. To close the chapter on your finances, I take it that you were reading and acting as a teaching assistant.
Avrett:Right, then I was self-sufficient. In fact, at the end of my first fall term, I was earning enough money so I systematically repaid my brothers and my mother.
DeVorkin:Was that part of the deal?
Avrett:Yes. It was a loan.
DeVorkin:You got married in 1961. How did you meet your wife, and her full name?
Avrett:Her name is Judith Reno Brett. At the beginning of my second year as a graduate student, I managed to become a resident tutor in Quincy House, and so that was a savings too. I had a free place to live; my duties were just to have dinner with the students and conduct one weekly science table, and just generally be part of the staff and accessible to students, and it was great. That first year, Quincy House had just opened, it was just built. I was the first person living in the building, because I had to move out of my place during the summer and I didnít have any place to live. I said, ďCan I move in early?Ē So I was walking planks!
DeVorkin:Before Harvard even accepted the building?
DeVorkin:Thatís interesting. They wouldnít let you do it today.
Avrett:The first year, the administrative assistant to the master was a distinguished elderly lady who had been working with him for a few years in preparation for the opening of the house, but then she left after that first year. A young lady who I got to know replaced her, so it was that summer, two years after I started graduate school, so it must be í59. No, it had to be í60 that I met her. I met her because I was a staff member of the house and she was the masterís secretary. I was also the Assistant Senior Tutor and I had some duties in the house so Iíd be working with her. So we got to know each other. Actually it must have been í59 we met, í60 decided to get married, and got married in í61.
DeVorkin:Is she from around here?
Avrett:She died eight years ago, so Iím a bachelor again. She grew up in Massachusetts, in Fall River or something. She lived in Boston.
DeVorkin:So she was a hometown or local person?
Avrett:Various places in Massachusetts, including North Andover, where she and her family lived for ten years. Her father was in the department store management field, and his job took him to Syracuse, but they liked the house they had in North Andover so much they kept it and rented it. We got married and lived for one year in Quincy house and then bought a house in Arlington and lived there for two years. Her father then offered us this house in North Andover because it was a house built in 1830 that required a lot of attention, and renting it wasnít working out very well. He was either going to sell it or negotiate with us to buy it. So we moved to the house that she had lived in, in North Andover.
DeVorkin:And this is while youíre still a grad student?
Avrett:No. I got my Ph.D. in í62, and we were married in í61.
DeVorkin:Yes, okay, so it was still a while after. Iím asking these questions to set the stage for your decisions after your thesis.
Avrett:Right, okay. Now, one of the primary things is that I had the opportunity to go to a meeting in England. It was a stellar atmosphere conference at the Royal Greenwich Observatory.
DeVorkin:A stellar atmosphere meeting at the Royal Greenwich Observatory?
Avrett:The old one, yes. And I met all the primary people in the field of stellar atmospheres: Dick Thomas, John Jefferies, Grant Athay, the French people, Jean-Claude Pecker. I presented my work, which was of interest to them because it was new and useful. Also, I met David Hummer, whom I collaborated with a year later in a nice paper. [Avrett, E.H. and Hummer, D.G., ďNon-coherent scattering, II: Line formation with a frequency independent source functionĒ, Monthly Notices of the Royal Astronomical Society, Volume 130, p. 295, 1965]. The people I met at that conference sort of immediately led me into the field.
DeVorkin:You were dedicated to that field at that time?
Avrett:Well, at that point, I became interested in the formation of spectral lines, which was a related but different problem from just the temperature distribution in an atmosphere, more subject to the rate of equilibrium.
DeVorkin:Moving from a thermodynamic to a totally physical or atomic approach?
Avrett:Right. At this point, I embarked on a very general project to be able to compute the spectrum of an atmosphere in great detail, including all the non-LTE effects, the formation of lines and the continuum, and started a general purpose computer program that Iím still using.
DeVorkin:Non-LTE was a big problem in the early Ď60s?
Avrett:It still is.
DeVorkin:It was a messy computational job.
Avrett:Yes. I was on the ground floor of that. Yes, I was in the group that was first attacking these problems with computers.
DeVorkin:And that group included you and Owen?
Avrett:Owen never did any non-LTE; he just did the LTE atmosphere and applied it to the sun, and then he stopped and moved on. But Iíd got into the non-LTE field, which is the formation of lines and continuum. There was Dimitri Mihalas, who was a contemporary.
DeVorkin:He was here?
Avrett:No, he came to the conferences and I got to know him very well, but we were never at the same institution.
DeVorkin:What were your decisions for where you would go upon graduation?
Avrett:I have a nice story. Are you going to be interviewing Chuck Whitney?
Avrett:He was in charge of the so-called ďStellar Physics Group,Ē you might say. He arranged to have me hired, and Kalkofen, and Owen, and a number of other people. Let me back-track just a minute to discuss Fred Whippleís organization at that time. He was the director, and he had the two assistant directors, one for science and one for administration. The science was Charles Lundquist, and he could tell you a lot.
DeVorkin:I would like to track him down.
Avrett:And then Carl Tillinghast (?), who I think has died. And then there was the staff. There wasnít any formal organization apart from the director and two assistant directors and a staff.
DeVorkin:Iím a little surprised, but Iíll tell you why in a second. But you keep going.
Avrett:Okay, but occasionally, there would be this team that Chuck Whitney was in charge of: the Stellar Physics Group.
DeVorkin:And that was what it was called, Stellar Physics?
Avrett:I picked up this term because when Chuck took this year leave of absence, a memorandum came around that, during Chuckís absence, I was going to act in his place as head of the Stellar Physics Group. Nobody had asked me. I never talked to Fred about that. Thatís the way Fred operated then. Have you heard the name Harris Rosenthal?
Avrett:Later, he was head of personnel. You should interview Harris Rosenthal, if heís still alive. I think he is. I think he lives in the Boston area, and heís a font of information and he can tell you everything. Now, he started out in the lowly position of sort of research services or something like that, but very capable, always aware of everything thatís happening. He would be one of these people who would check with this guy and check with this guy and make arrangements, and everybody would be happy.
DeVorkin:He worked for Tillinghast?
Avrett:Who knows? I donít know who he reported to, maybe to Fred directly. But I think he looked around, and he said, ďIf Chuck leaves, I should take his place,Ē and he checked with me, ďIs it all right with you?Ē and I said, ďOkay with me.Ē
DeVorkin:This is already later in the Ď60s?
Avrett:Yes. Then everybody got this memorandum that I had been put in this position. So there was this so-called Stellar Physics Group. Maybe it was called Stellar Theory. Yes, maybe thatís it.
DeVorkin:Yes, and this is 1963, from the Smithsonian Reports, 1963.
Avrett:Thatís probably what it was from.
Avrett:The Stellar Theory Group. I remember it as Stellar Physics, but I never saw any formal organization of that nature. It was basically Whipple and his two assistant directors and the staff. But then if there was any reason in reporting to SI to group things, then such names were made up on the spot, but it really wasnít part of the formal organization.
DeVorkin:Iím showing you the SAO divisions and programs in 1963, and all of these are organized by program.
Avrett:Yes, this was just what seemed to make sense that month. [Chuckles]
DeVorkin:Okay. It is helpful for us to understand whoís working on what problems and that sort of thing. We took Whippleís reports in the AAS and also in the Smithsonian reports and we put them together, because they werenít quite the same, and generated name lists, generated these programs, and of course, the divisions as he described them, so there was a Stellar Theory Division. Iíve got a lot of questions, but before I get to that, you mentioned that you were aware, when you came as a grad student, that there was a lot of orbit theory and orbit calculation going on, and they needed people who could calculate and do things. Did you ever do any of that?
Avrett:No. Whitney was involved in this, and Krook was involved to some small extent. They never asked me to do anything. I think I was coming in too late. I think they had the problems at hand by the time I was around.
DeVorkin:Now weíre talking '62, '63, when you were working with Krook. Okay, so there wasnít that pressure. But what was happening was that Whitney himself was moving back to stellar atmospheres.
Avrett:Right, thatís true.
DeVorkin:Were you aware of it then, and did you talk to him? How did he feel about this mission duty of orbit calculation?
Avrett:I was aware that he had been heavily involved in the orbit calculations, but I never really discussed that with him. And yes, he had done his early work on velocities in stellar atmospheres. I saw some of those papers, and he encouraged the development of the stellar atmosphere theory. At one point, he had a grand plan that he would be the author of a book on stellar atmospheres, with several of us writing chapters, and he worked very hard on that. I still have the latest version of his stellar atmospheres book, because he taught the stellar atmospheres course, and it was an outgrowth of that.
DeVorkin:What happened to the book?
Avrett:Mihalas published his own book, and so it didnít seem to be needed at that point.
DeVorkin:Oh, what a hard act to follow.
Avrett:Yes. So the initial edition of Mihalas is what came out when Whitney was halfway through doing that, and that seemed to be the book.
DeVorkin:So it was a book more like Mihalasís than like Lawrence Allerís?
DeVorkin:It must have been observational astrophysics oriented, with theory supporting.
Avrett:He was sort of relying on several of us to put our specialty into some concentrated chapters, and his contribution up to that point was more or less the overall introductory radiative-transfer, the kind of thing you find in Kourganoff if you remember that, and just the early development of the theory. Nothing really came of it.
DeVorkin:Before we get too far into your development of your work at SAO, let me back up and say youíre a Harvard Ph.D. in stellar atmospheres, but in physics.
DeVorkin:Wasnít the world at your feet, beating down your door?
Avrett:I have a nice story of that. I had finished my Ph.D. I asked Whitney at some point, a couple months before, [because] Whitney was acknowledged as the SAO person involved with stellar atmospheres to who I should coordinate everything, so that was clear. Krook was my advisor on the mathematical theory, but Whitney was the coordinator of the stellar atmospheres research.
DeVorkin:So he ex-officio became kind of like your advisor as well?
Avrett:Yes. So I think everything I wrote, I would show to Whitney as well as Krook.
DeVorkin:Okay, so he was totally clued in. And you mentioned that you moved up here?
Avrett:Yes, I shared Max Krookís office in Building A while Building B was being built, and then as soon as Building B was built, they gave me an office there. So I moved down the same time Whitney and everyone else did. But my story is that I was finishing my Ph.D. I asked Chuck one day, ďCan I get a job at SAO?Ē And he said, ďSure,Ē and heíd work on it, and I guess heíd discuss this with Whipple and so forth. So I was offered a civil service position with the Smithsonian. I asked, ďIs this permanent?Ē He said, ďYes,Ē and thatís all there was to it. I think I must have filled out an application of some sort, but basically, the job was offered to me. Now, my story is that after this had occurred, I got a letter from Jesse Greenstein offering me a post-doc at Caltech; I never replied to the letter. I have better manners now than I did then. I mean, just a letter came out of the blue offering me a post-doc. I guess jobs were easy to find then and it just didnít occur to me.
DeVorkin:You hadnít moved into your father-in-lawís house yet?
DeVorkin:So that wasnít a factor?
DeVorkin:Iím just thinking, were there any personal factors for you to need to stay here?
Avrett:No, I didnít want to move because I wanted to maintain the continuity of what I was doing here. I was involved with so many things and Iíd been offered a very nice job. I didnít realize how valuable that was then.
DeVorkin:Itís still, you know, a permanent job over a post-doc, unless it was an unbelievable post-doc. I would imagine that would be almost like a no-brainer. So you didnít search out any jobs or anything?
Avrett:No, I never did.
DeVorkin:No active search. So here you are, 1963, and you move into the Smithsonian. You were aware of the Smithsonian, then, as distinct from Harvard?
DeVorkin:Did you have any sense that you were not part of the inner Harvard family or the Harvard family at any point in the beginning?
Avrett:Well, actually, I knew where all the money came from, the sources and support, and so I was fully aware of all those technicalities. I was a resident tutor of Quincy house involved with the instruction of undergraduates and graduate students, including being the thesis advisor of people like Steve Strom and occasionally teaching astronomy courses. I knew that I was being paid by the Smithsonian, and I knew that I wasnít a professor in the astronomy department, but I felt totally involved in the program. I just regard these as the administrative arrangements and the sources of funding, the way this place was organized, and it was all perfectly honest; there was no conflict of any sort.
DeVorkin:Did you ask for or ever consider a Harvard appointment?
Avrett:Nobody ever offered this to me. I remember, many years later, for two years running, I taught the course called Radiative Processes in Astrophysics, and thereís a book by George Rybicki and Alan Lightman by that name. Rybicki had tired of teaching it and was going on to other things, so I taught it two years in a row, and the third time I was asked to teach the course, I said, ďWhy donít you make me one of these nominal professors involved?Ē The response was silence and they found somebody else to teach the course, so I didnít offer again.
DeVorkin:How did you feel about that? About when was this?
Avrett:I knew that it was a long shot, because the field of my specialty isnít regarded as the greatest new field. No, thatís all right. Iíve just accepted that reality.
DeVorkin:What was the rationale for Chuck Whitneyís group, letís say? I mean, heís moving back into stellar atmospheres, and heís building up a group as he does. And youíre one of the products, Owen is. Is that a reasonable way to look at it?
DeVorkin:Max Krook was involved in it, but he had a separate appointment, of course.
Avrett:Yes, the reason, of course, was Celescope.
DeVorkin:Thatís what I wanted to figure out.
Avrett:Yes, definitely. We were there as the theoretical backup of Celescope. Now, some of the people involved didnít want to get involved with Celescope at all, and I was happy to whenever there were things to do. One of my publications is a companion volume to the Celescope catalog.
DeVorkin:In the Ď70s, yes.
Avrett:Have you seen that?
DeVorkin:I havenít seen it yet, but I know what it is.
Avrett:I have it here. Thereís the Smithsonian book called Celescope Catalog of Ultraviolet Stellar Observations, and then a companion book called Blanketed Model Atmospheres for Early-Type Stars, [Washington: Smithsonian Institution, 1974] and the authors Robert L. Kurucz, Eric Peytremann, and Eugene H. Avrett.
DeVorkin:And these are models?
Avrett:These are models with all the data necessary to compare with the Celescope observations. These are the band passes.
DeVorkin:Weíre looking at page 118 of the Blanketed Model Atmospheres for Early-Type Stars, and these are all the band passes for the Celescope cameras.
Avrett:This is the theoretical energy distribution for stars of these parameters. If the star had this flux as a function of wavelength, then the product of these band passes and the flux would give you the colors of the indices that are observed by the Celescope, and that product is printed here. So you could compare the observations with the theory, assuming that weíve constructed the stellar spectrum reasonably well.
DeVorkin:These are two different stars?
Avrett:No, this is the same [star] plotted in different ways. This is versus wavelength and the other is versus frequency, and thereís a rate distortion. Itís the same thing plotted in two different ways.
DeVorkin:Oh, I see. Now, is there anything that I can tell by looking at this? Because, of course, the band passes are all nominally limited here.
Avrett:This is just a scale from zero to one halfway up the graph. This just tells you how wide it is.
DeVorkin:Oh, so this tells you that youíre looking at this part of the spectrum, right above it?
Avrett:Right. And this tells you youíre looking here, but in a fairly broad band, a much broader band than this. Thatís all.
DeVorkin:Now, how did you generate this theoretical continuum? Because thatís what this is?
Avrett:Right, so using the methods that I did for my thesis and further methods, given the energy flux from a star and its gravity, you can calculate what the spectrum should be, and thatís what weíve calculated. Here are stars of all different types of effective temperatures and surface gravities and the spectra from each of them, and folding that in with the Celescope band passes to give what the Celescope would see if you were looking at a star just like that.
DeVorkin:So youíre going from 1,000 angstroms here, it looks like, on the upper graph, up to about 6,000 angstroms, 7,000, almost into the red. But the primary interest, of course, is sitting around here. The Balmer discontinuity is right here, this abrupt jump.
DeVorkin:So youíre looking for various features that you expect to be there as a function of the spectral class of the star and stuff like that.
Avrett:Exactly. Yes, thatís right.
DeVorkin:Okay. I know weíre jumping way ahead, but what youíre looking to see is how well the data fits the way your predictions would be, right? And how did it do?
Avrett:Not a great deal was done with this. What weíve done is very clear-cut. These were the state-of-the-art calculations at that time of the flux distribution.
Avrett:Primarily they are calculations by Robert Kurucz. But there are lots of more lines and complications in subsequent calculations.
DeVorkin:How is the one on page 118 different than the one on page 119? Oh, I see, different temperatures.
Avrett:Different temperatures and surface gravities, so you change the gravity of the star by this factor and the spectrum changes.
DeVorkin:Factor of ten, actually, going two to three. When youíre going up to higher gravity, that would probably be a dwarf star?
DeVorkin:What Iím trying to get at is how to characterize how successful the observations were in either supporting the predictions, or did you doubt the predictions?
Avrett:I think the overall statement is that the Celescope accuracy was a little bit disappointing in that they had a lot of problems with calibration, and so there were big error bars on all their observations. But they managed with a great effort to finish everything as proposed, in a reasonable way. It wasnít a huge success because of the technical problems, and maybe five years later, there were other satellites that did a better job. So as soon as there were better resolution instruments, then all of this was put aside. It was an early satellite experiment that managed to be completed successfully, but just barely. This companion volume was just to add a little bit of luster to it.
DeVorkin:I see. Was this your primary involvement in Celescope then? Preparing this companion volume?
Avrett:I did this just as a publication to go along with this; it wrapped things up nicely.
DeVorkin:Thatís like 1970-something.
Avrett:Yes. I canít remember. Now, this was published by the Smithsonian Institution, and the office there was terribly slow in dealing with that.
DeVorkin:í74. Oh, yes. The telescope flew in í68.
Avrett:Yes. They took two or three years to publish this.
DeVorkin:Yes. So youíre saying that this is work you did say around í70, í71 with the data.
DeVorkin:Okay. Now, Celescope was supposed to fly in the early Ď60s, and I imagine you were quite well aware of that.
Avrett:I remember, yes, when it flew.
DeVorkin:What contact did you have with the actual developmental side, and how aware were you of all the problems they were having with it?
Avrett:Whitney took the sabbatical and I suppose I was thrust into this position after I became Whitneyís sort of replacement.,
DeVorkin:This is late í60s.
Avrett:Yes, right. I think it was at that point, the year of his sabbatical that they were trying to finally solve the basic calibration problems of Celescope. The problem is that each image of each star field that they had, the accuracy was not great enough to translate that into absolute terms.
DeVorkin:Now, this is not digital data?
Avrett:No. This is Vidicon.
DeVorkin:Your data is like an image on a videotape.
DeVorkin:And how do you analyze that anyway?
Avrett:Exactly. So they had these images with these little blots of white stuff. [Laughs]
DeVorkin:Yes. Iíve seen some of them. They look pretty crude, which is not surprising.
Avrett:Yes. And so what do you do with them? The way they did this is they had an image of the entire sky with lots of overlap between these images. So you have this image, and then you had another image and another image and another image, and then you put them all together. Itís the same star — and you assume itís not variable. [Laughter] So you can tie everything together, but you need the whole sky all at once and a huge computer thing to be able to do that.
DeVorkin:In other words, to calibrate one field against another, so that when youíve got this magnitude system, it means the same thing for every plate.
Avrett:Right. So you have this image, and then you have four overlapping images.
DeVorkin:Werenít there any instrumental standards or instrumental calibration? I remember that any photometric [instrument] would have a calibration strip of some sort.
Avrett:They had very limited calibration.
DeVorkin:Was that an oversight?
Avrett:No, I think it just didnít work, or something like that. They had to do everything on a relative basis. So if you had these overlapping imagesÖ
DeVorkin:They didnít plan on that.
Avrett:No. That was after all the data had been collected so they had the entire sky worth of data. They had to use all the overlaps to put it all together in a consistent, relative basis.
DeVorkin:Okay. This looks like somebody pulled the proverbial thing out of a fire.
Avrett:[Laughs] Right, yes.
DeVorkin:But this just sounds like a disaster for a lot of data.
Avrett:Yes. It was a near disaster, right, because we were faced with the enormous embarrassment to the Smithsonian of, ďHere we spent all this money and we have all this data, and we canít do anything with it. Sorry.Ē [Laughs] So there were weekly meetings that I was drawn into.
DeVorkin:Who were in these meetings?
Avrett:Fred Whipple, Chuck Lundquist, Bob Davis, Cecilia Payne-Gaposchkin, her daughter Katherine Haramundanis, Katherineís husband Edward, who was a mathematician, and Mike Gaposchkin.
DeVorkin:Katherineís husband was on the payroll too?
Avrett:To some extent, I guess. Just to work on this problem. Those are the principal people, I think.
DeVorkin:And so you met weekly.
DeVorkin:What were those deliberations like?
Avrett:That was just simply dealing with the computer details of matching all of this. The problem I was assigned was to look at it from an applied mathematics point of view. I donít know whether Rudy Loeser attended all the meetings. Here you have a plane above which there are a number of points at different heights in the plane — not in a square grid, just random data points with heights above the plane and you want to put a surface through those data points. In other words, you want to be able to interpolate from that to positions where you donít have any data. But itís all irregular.
DeVorkin:I take it those points are stars?
DeVorkin:And each star has a different brightness.
Avrett:Well, you see, you have a star at irregular positions in the sky. The problem was that they had some calibration at one set of grid points. But of course, the stars would be anywhere but there was a lot of distortion in the grid points for which you were trying to establish the calibration. At least you would lay down a grid, and establish the calibration at some standard set of grid points, but the star is never going to be at one of your grid points, and so you have to say, ďWell, what would be the calibration where the star is located?Ē For a given field of view, you laid out a grid pattern, and youíre trying to establish the calibration of the instrument at the points of that standard grid. Well of course, the stars going to be looked at are different here than when you move it here so youíre going to have to interpolate.
DeVorkin:The different part of the cathode.
Avrett:One thing I discovered is that somebody had made a very simple decision to interpolate according to the nearest point, which leads to discontinuities. In other words, if youíre at two grid points: hereís a star located roughly half way between the two grid points. If itís closer to the first point, youíre going to put the calibration at that value. If itís closer to the second point, youíre going to put the calibration at that value. Youíre going to have discontinuities, and so they were plagued by discontinuities just from a too crude interpolation. One thing I put into this is the simplest interpolation. Say if you had four points in space at different heights above a plane, but looking down, itís not a rectangle...Draw a line around the periphery of these four points in space. Now, if you take a roller and roll it along two opposite edges keeping the ends in proportions to the lengths that forms a surface. If you take the roller and roll it along the other two edges in the same way, it forms the same surface, even though itís a very warped surface. So this is called a rolled something or other. But thatís the three-dimensional equivalent to a trapezoidal rule, a trapezoidal rule in an extra dimension. Thatís just a simple concept. I never saw that in any book. I just figured it out.
DeVorkin:Were you the one who set up the correcting system?
Avrett:Rudy and I just did the little program to do their interpolations. It was just a fairly simple applied mathematics [exercise], but very practical and controllable. Thereís no chance of this going wrong.
DeVorkin:It seems like this was the key, the way out of the problem.
Avrett:They had to get rid of some of those discontinuities that were just messing things up, and this was a smooth way of doing it. Now, Katherineís husband, the mathematician, said that he had the much more elegant way of doing it, but we finally ignored him because his approach seemed too complicated.
DeVorkin:Who made the decision?
Avrett:I donít know. It just evolved in meetings.
DeVorkin:What was Fredís role in this?
Avrett:Fred wanted to make sure that things were happening, so he would attend every meeting. He didnít have much to contribute except to make sure that people were thinking about everything.
DeVorkin:Do you remember his attitude or his demeanor? Did he set the flavor of the meetings?
Avrett:He just found the whole thing slightly painful. Right. [Laughs]
DeVorkin:The fact that he was meeting with you, was that a bit scary?
Avrett:Oh, that indicated his priority. We were working for him, so yes, weíd be there.
DeVorkin:What about Bob Davisís contribution? Did he run the meetings?
Avrett:He was always very energetic and running around doing things, but he just accepted the point that things were getting beyond him, of what he was able to do by himself. He was appreciative of help from any quarter, and he never had any problems with anybody else, and no one had problems with him.
DeVorkin:What was his contribution, then, specifically to working out this method?
Avrett:I donít think he had very much to do with it.
DeVorkin:But he had to be there?
Avrett:He had to be there, right.
DeVorkin:Was that uncomfortable in any way, do you think?
Avrett:No. There were no conflicts that I witnessed. Now, maybe there were.
DeVorkin:Well, but nothing at the table anyway.
Avrett:Nothing at the table. Right.
DeVorkin:And what was Cecilia Payne-Gaposchkinís input?
Avrett:Well, of course, she was the expert on stars. Her daughter Kathy was involved, and her son Mike was involved, even though he was not connected with Celescope at all. I think he was head of the computer center, so he was involved in that point of view.
DeVorkin:He was. This is after Leo McGrath retired.
Avrett:I never knew McGrath.
DeVorkin:He was the Director in the computer center before the í70s, in the í60s. I interviewed him primarily for his Baker-Nunn work. He was one of the station people, but then he ended up back here. What were Robert Kuruczís and Eric Peytremannís involvement?
Avrett:Kurucz is still here. He was also my graduate student. He was involved in the stellar atmosphere calculations. He had a better program for doing these particular calculations than I did. I was primarily concerned with methods and also the non-LTE aspects. He did his thesis under Steve Strom to set up a program to do the standard radiative equilibrium — LTE — atmosphere, and thatís what this is. He had collaborated with Peytremann, who is in France, I think, on some of the line blanketing, incorporating opacities.
DeVorkin:Did you ever call yourself anything at any point in this deliberation on this committee?
DeVorkin:Did other people call you anything, you being the committee, collectively?
Avrett:No. Not that I recall.
DeVorkin:Okay. Was there any point where you knew you had a solution and a way to go that would carry out to a respectable ending?
Avrett:Yes, as soon as some of these problems of the discontinuities and some other minor things were straightened out. It should have been done properly to begin with rather than so crudely and had to be corrected later — then they made repeated runs of the whole global database and had worked out various bugs and deficiencies. Finally there was a fairly high degree of consistency, and they said, ďWell, okay. Now it works, and this is it,Ē and we published it. And that ends the project. NASA was just saying, ďFinish this up and give us your final report, and letís end the project. Letís end it successfully.Ē
DeVorkin:Anybody at NASA that you communicated with at that time? Were you at any level?
Avrett:No, but the general view of the astronomical community at that time was that this was a marginal project. There had been a competing effort, OAO — Orbiting Astronomical Observatory, OAO-1 — built by Goddard Space Flight Center, that would have done this ten times better. But it failed in launch and it was lost.
DeVorkin:But SAO was one of the original proposers — Whipple was one of the original PIs.
DeVorkin:SAO, Goddard, Wisconsin, and Princeton, thinking of all the groups that were part of the OAO Program, once it was defined. Of course, stuff going on at NASA was just Byzantine compared to this. Originally, they wanted to throw everything — solar and stellar — on one platform.
DeVorkin:Did you know that?
DeVorkin:Oh, it was crazy. And then finally, they split it into OAO and OSO. I know you did a little bit of reduction and work on OSO, then, too, right?
Avrett:Oh, yes. Right.
DeVorkin:Goddard was on the first flight, youíre right. But thatís only because SAO couldnít get their instrument ready quick enough. Were you aware of that?
Avrett:I think I heard that.
DeVorkin:They were having trouble with the UV tubes.
Avrett:So SAO went subsequent to that first failed flight , when the Celescope went up?
DeVorkin:Yes. They were removed from the first flight, the Goddard experiment flew.
Avrett:I guess what Iím thinking of is a third flight that failed because I know Nancy Roman was involved in an experiment that was going to be so much better than Celescope. They were saying, ďLetís cancel Celescope because this is so much better.Ē
DeVorkin:This was before Celescope flew?
Avrett:No. Celescope had already flown. It was maybe in orbit, maybe in data analysis and this was just about to fly.
DeVorkin:Would that have been the Princeton OAO-3?
Avrett:And only because it failed was Celescope allowed to finish its final report [Laughs] because there was nothing else. So, there was a third one, and it was a big one.
DeVorkin:Oh! It was one of the OAOs.
Avrett:Yes. Maybe it was OAO-3 or OAO-2 or something.
DeVorkin:Iíll check. I know that the first one failed completely, and that was '62. But by then, the Smithsonian was already off the manifest because it was having trouble getting ready. There was not another launch until í68, which was the Smithsonian and the Wisconsin Experiment Package.
Avrett:Oh, right, Wisconsin was on the same flight.
DeVorkin:As far as I know, wildly successful.
Avrett:Yes, Wisconsin was very successful. But then there was a flight [before] that that failed.
DeVorkin:Thatís what Iíll check out. Okay. OAO B was launched in 1970 but the shroud failed to open. The single instrument was a Goddard Space Flight Center spectrophotometer fed by a 36-inch telescope.
Avrett:I can remember that Celescope was in trouble in its data analysis, or the disappointments relative to the problems with calibration and sensitivity..
DeVorkin:So they knew that they were in trouble when it was in orbit sending data down?
Avrett:Right, yes, it was not quite the quality that they had anticipated.
DeVorkin:When were you called in or when did you become aware of this? Or was everybody aware of it?
Avrett:It was only when I was told to start coming to these meetings.
DeVorkin:Who told you?
DeVorkin:Lundquist, okay. This was after you took over the group, and Charles Whitney was out of the picture?
DeVorkin:Did you talk to Charles about this at all?
Avrett:No, I didnít. I have always regretted a little bit not asking him when he came back, ďWhat happened?Ē [Chuckles] But I just never did.
DeVorkin:Yes. Where did he go?
Avrett:Well, he just worked at home for a year. He didnít go any other place; he just took a sabbatical and started writing, maybe his galaxy book or something.
DeVorkin:Discovery of the Galaxy, I told him yesterday, that thatís one of the things that got me into history. That was a great book.
Avrett:Oh yes, heís a good writer.
DeVorkin:I can see why, in the way that he described it, because he knew that he was writing an astronomerís history. I was a junior astronomer reading it and it appealed to me much more than, letís say, some of Gerald Holtonís work. [Laughs] Iím sorry. I have to put that on the tape. My comment.
Avrett:[Chuckles] Iíve never read much by Gerald Holton, actually.
DeVorkin:So there was a point where Nancy Roman said, ďLetís cancel the data reduction because whatís going to go up is so much better.Ē
Avrett:Or at least it was felt here that if that had been launched successfully, then they would have said forget it for any more funding.
DeVorkin:This was a fear, a concern?
Avrett:Yes, it was just a concern here. Then when it failed, we said, ďOkay, now we have a chance to at least wrap things up.Ē
DeVorkin:Exactly. I see. So you were brought in to do this. Letís discuss the rationale for the Stellar Theory Group, that was, as you said, originally rationalized in support of Celescope. And you came into the group in '62, '63.
Avrett:Yes, my position was started in '62.
DeVorkin:By then they knew that Celescope wasnít flying yet and that it was going to be a long period of gestation.
DeVorkin:Did you do anything during those periods in preparation?
Avrett:Never was asked to.
DeVorkin:So this was kind of like a research reserve kind of mentality?
DeVorkin:Do you know that term, ďresearch reserveĒ?
Avrett:I was told that Fred Whippleís viewpoint was that because we were going to get these stellar observations, there should be a stellar observational theory group to interpret them, and so he was willing to just let a group flourish on its own merits. I saw no particular need to do anything in preparation for the Celescope launch.
DeVorkin:Just remain active, keep your theoretical tools up-to-date?
Avrett:Yes, just go according to the progress in the field.
DeVorkin:So that you could take advantage of it? You didnít go to the launch or become actively involved in any way; you were just there waiting?
DeVorkin:Now, letís go back to the report. You devote a lot of space in the report to these graphs — there are dozens and dozens of these. What is the purpose of the visual display here? What does it help me understand?
Avrett:I felt that [could not be] just a book of numbers [laughs]. I mean, it added some interest. Also, I had not worked with all of these stellar spectra of the variations with effect of temperature and gravity and how the thing is shaped and features because I had never really seen this myself. I thought this was a very useful visual element to see how the spectrum changed. If youíre referring to the Celescope colors, where in the spectrum do they refer?
DeVorkin:For instance, this particular filter is a combination of the sensitivity of the detector and the filter band pass.
DeVorkin:Thatís an instrumental profile, one of these little peaks here.
DeVorkin:Okay. Weíre looking at page 142 at random. Itís sitting right under the Balmer Discontinuity.
Avrett:Yes. Maybe it doesnít tell you so much, but if you take the ratio of the Celescope colors that youíve got from these two wavelengths.
DeVorkin:Any two of the colors, or the one that is peaking at 4,500 and the one that is peaking at 5,500, say.
Avrett:See, the number the Celescope will give you would be the product of the stellar flux and the sensitivity curve. And here, itíd be the product of another. Youíd expect this number to be bigger than that number because the flux is moving to a higher value. If it were going down the other way, you would expect this number to be bigger.
DeVorkin:Right. So that is a quick way of seeing if youíre on the right track, first-order.
DeVorkin:So thatís what these are for.
DeVorkin:Okay. Again, Iím referring to the instrument profiles. These are not in any way indications of the actual Celescope data. You have to go to see the numbers in the table to see which way itís going.
DeVorkin:Is there any tabulated chart in here that shows the discordance or the deviation between Celescope data and your theoretical data?
DeVorkin:So where did that discussion come out? Is that in the front? But thatís not what this book is about.
Avrett:No. This basically gives you the tools to be able to interpret the Celescope data without saying too much more than that.
DeVorkin:Okay. If I were to use one of these graphs, letís say this one. Weíre looking at page 29.
Avrett:See, there are lots of lines.
DeVorkin:Yes. This is a much higher resolution. Did you actually model the lines?
DeVorkin:Okay. So you were doing rather high resolution. This is Wayne van Citters and Donald Morton stuff, average over distribution function. I see. So youíre now looking at the hydrogen spectrum here.
DeVorkin:That is really neat. If I were to take one of these as an illustration for my history of Celescope, what one would make the most sense to you?
Avrett:[Laughs] I donít know. Itís been such a long time. Iíd have to look through this myself.
DeVorkin:Well, Iíll certainly be sending you a rough draft, and then you might suggest at that time.
Avrett:Why donít you borrow this book?
DeVorkin:Oh, I can get this. I know I have that catalog. I donít have this, which Iím kind of surprised about, but I can get it. If I canít, Iíll definitely ask for it.
Avrett:Actually, at the beginning of this, there are a few things I just noticed. Here are the UVB System and the various existing systems.
DeVorkin:Weíre on page 19, and itís the upper and lower graphs showing the UVB filter band passes or the instrumental profiles. And then all of these little Us — U1, 2, 3, 4 — are the Celescope?
Avrett:Celescope. Yes, right.
DeVorkin:And what about the UVB and Y dotted line?
Avrett:Thatís another visible system.
DeVorkin:Oh, okay. Oh yes, this is a Y-band pass; thatís an intermediate-band pass?
Avrett:Right. And this is just showing the relationship between the customary ground base band passes and the Celescope band pass in relation to theoretical stellar energy distributions for the different temperatures.
DeVorkin:Yes, I see that. Youíve got your 60,000 degrees, this of course is your hottest imaginable kind of star. Youíre still talking about a B-type star at 30,000 and 20,000 A-type, maybe. I see. Is this showing you that youíre much closer to the theoretical maximum for these?
Avrett:Right. See, none of these are really going to the maximum. But nevertheless, the slope is going down here and itís going up here, so if youíre comparing these two ratios, you could distinguish between the two.
DeVorkin:Yes. So you can get temperatures and classes that way?
DeVorkin:Okay. Thatís neat. Oh, the Stromgren System is this intermediate one. Thatís right.
Avrett:Right. This is some basic stuff here.
DeVorkin:I certainly am going to use this. Weíve come a fair way, but we jumped into the future, I think. I have this feeling that weíre missing a good bit of your work in the í60s. We have the teaching, also, to talk about — the course loads, the Smithsonian, the Harvard relations to the extent that they affected you. So how would you like to proceed?
Avrett:Well, one thing I think is reasonably significant in an overall sense is that I was Ph.D. thesis advisor to nine graduates in the Harvard Astronomy Department. In the 1960s, Steve Strom, Frank Stienon, John Rich, Jeff Linsky, and Jay Pasachoff, and in the early 70s, Bob Kurucz, Ted Simon, Eric Chipman, and Jorge Vernazza. Iíve mentioned my collaborations with Steve Strom. And Jorge Vernazza was a major collaborator for the three well-cited papers on the structure of the solar chromosphere. Menzel passed Jay Pasachoff on to me to see if I could help him finish his Ph.D. The material was okay, but it needed a lot of careful work and exposition. And it turned out that Jay was fluent as a writer but needed much editing help. He had no compunction about pouring stuff on the page, but it needed lots of work. And so he would pour page after page of rough material on me, and I would heavily blue pencil it and send it back to him several times. We finally got his thesis together. He never had any reticence in writing, but he really needed an editor, and I seem to have been his first real editor. I spent a lot of time with him on his thesis and we finally got it basically correct. Or at least not wrong.
Avrett:This is Pasachoffís thesis.
DeVorkin:ďThe Fine Structure in the Solar ChromossphereĒ, Pasachoff (1969). And your thesis consisted of two published articles with an introduction?
Avrett:[Laughs] Right. I never did anything like this. And this went through ten drafts, Iím sure. [Laughter]
DeVorkin:How do you think he became one of the best textbook writers?
Avrett:Apart from the thesis editing, I was one of the people writing glowing letters of recommendation to Williams College to get him hired there. Once he started teaching all the time, he just kept getting it all together and then he wrote these very successful books.
DeVorkin:What is the significance of putting a cartoon by Donald Menzel in as a frontispiece?
Avrett:Well, Donald Menzel was his hero.
DeVorkin:But he wasnít a student of Menzelís?
Avrett:No, not really. But Jay accompanied Menzel on eclipse expeditions, later becoming prominent in eclipse observations.
DeVorkin:Jay actually says he got his start in astronomy through Project Moonwatch.
Avrett:I had forgotten his early participation with Moonwatch.
DeVorkin:Letís move on to the conferences on stellar atmospheres. Whose idea was it for the conference, to develop it, and to what purpose?
Avrett:I was certainly one of the organizers. The year previous I had been to this stellar atmospheresí conference at the Royal Greenwich Observatory in England. Maybe it was partly a follow-up to that and there were many of the same people. Steve Strom was doing his atmosphere calculations with Kuruczís help, who was his student at that time.
DeVorkin:He had graduated by then?
Avrett:Exactly when Steve finished his Ph.D.? Letís see if I have it.
DeVorkin:Because youíre working with Steve in í64. Now, this is also a thick one [another thesis].
Avrett:Thatís Steve Stromís thesis. This is a grid of model atmospheres.
DeVorkin:Did you have to edit his too?
Avrett:No. He was very good.
DeVorkin:Itís got flow charts in here. This is the logical organization. Now, relating to this conference but also to your collaboration with Owen, he was doing the computing and youíre doing the theory. At this point, computers were not transparent, shall we say. They were batch process. The Smithsonian had its own computer, so you always were computer rich in everything. But what was the actual integration of the computer into your research program, or how did the computer change your research program, your whole basis of applying theory? Did it have an influence in how you chose to construct your theory?
Avrett:It was assumed that computers would be used just because the easy problems that could be done analytically had already been done and there were a few things, occasionally, that could be done along those lines. But a combination of the analytic derivation of methods and procedures, and then using the computer — I mean, quite often, the computer wasnít used in a brute force way; you had methods devised that the computer would just simply carry out what you could do by hand very laboriously. We just basically viewed this as a faster way of doing things, faster than you could do by hand.
DeVorkin:When you looked for students, did you start thinking in terms of students who were adept with computers? Was that part of your selection criteria?
Avrett:Usually with the students, it was just assumed that they were computer literate. In fact, the students were always more computer literate than we were. [Chuckles]
DeVorkin:I know that at a number of astronomy departments in the early í60s, access to computers for the students was far more limited than for the faculty. There was a worry that the students might destroy the computers or something like that.
Avrett:Oh. That was never the case here.
DeVorkin:Not here. This was a place where your grad students could get direct access and compile their own programs?
DeVorkin:Was there a central computing facility here at SAO?
DeVorkin:So you didnít have to go beyond SAO for your computing.
Avrett:No. Sometimes the computer center was in another building a short drive away over in the Alewife Shopping Center, Route Two. It was 185 Alewife Brook Parkway. There was an office building there, and the computer center was located there.
DeVorkin:Was that a Smithsonian rental?
Avrett:Yes. SAO rented that building. So coming back to Strom, it was basically at this time that Steve had things to report, as I did, and it just made sense to organize a meeting, a gathering of the experts. I think we had a series of three meetings in four years.
DeVorkin:Yes. Where did you get the money?
Avrett:I think Chuck Whitney handled all of that. He might have gotten a grant. I was never involved with fundraising. He probably got a grant, or maybe the Smithsonian contributed something to it. With travel funds, I think we probably had to pay the travel expenses for some of the Europeans.
DeVorkin:Was there a Celescope tie in?
Avrett:Never explicitly at all. Celescope was hardly ever mentioned in any of these conferences, which is sort of remarkable. There was never any presentation of Celescope data at any conferences. Now, maybe this was earlier than the launch.
DeVorkin:This was much earlier than the launch. Yes, this was in í64. Quite right. In other words, there didnít have to be a presence for Celescope. I read the introductory remarks by Erica Bohm Vitense that this was ďa straight conference on model stellar atmospheres. Proceedings principally comprise text provided by the participants. Discussions from the floor were tape-recorded and have been summarized and paraphrased by the organizing committee for inclusion in these proceedings.Ē
DeVorkin:How did you feel about the field from the results of these conferences? Were people feeling that this was the formation of a specialty, a sub-discipline?
Avrett:This was most of what astrophysics was in those days. We were aware that some people observed galaxies, but you couldnít do much with them. [Laughter] And it was too early for a lot of the exotic, high-energy stuff, and nobody knew anything about the x-ray spectrum.
DeVorkin:Thatís right. Looking at some of the titles, the one that strikes me is actually the last one on the abstract, itís a very long abstract, and itís by Lawrence Aller, and itís ďTheoretical Model Atmosphere Data Needed for Interpretation of Observational Material.Ē The question that rises in my mind because of this is that thereís always this little tug-of-war or a race between observation and theory. Where was the field at that time as far as theory and observation? By implication with Allerís paper, heís an observationalist asking for more theory.
Avrett:I continue to use his book. I find certain things in there far more valuable than Iíve found any other book.
DeVorkin:Aller was wonderful at teaching astrophysics.
Avrett:Yes. The Atmospheres of the Sun and Stars is a wonderful book, and itís full of theory as well as observations. So he just really bridges both fields. He never got into non-LTE calculations, but all the underlying physics is there. He was a very perceptive person to understand both subjects. I think he was looking at it from a very general point of view. I never saw much conflict. The observers were not always comfortable in publishing colors of stars and things like this. [Laughter] I think theyíve gotten to the point where you needed some theoretical framework in order to proceed any further.
DeVorkin:Well, thatís sort of what I was groping towards in the context of Celescope in my mind, even if Celescope is actually irrelevant as a guide through your group for the í60s. And it looks like it was pretty irrelevant. You agree with that?
DeVorkin:But in a sense, one might think that Aller was giving a paper saying, ďWell, youíre going to have all these ultraviolet observations, and youíre going to have to interpret them where you donít know anything about whatís going on in the ultraviolet flux of the star,Ē that kind of stuff. He wasnít saying that?
Avrett:No. It was just never mentioned.
DeVorkin:Was there a feeling on your part at all that you had to do these ultraviolet continua?
Avrett:Occasionally, there would be some mention by somebody about why we were hired. Because of Celescope we were expected to fit in some way, but Fred never pushed it, and Chuck Whitney never pushed it. They seemed to be happy with letting the stellar theory field develop on its own merits.
DeVorkin:You did do some work, and I can quote you. All right?
Avrett:Okay. All right.
DeVorkin:You and Steve Strom wrote a paper, ďComparison between Model Atmospheres and Spectra from Early-type Stars,Ē [Avrett, E.H. and Strom, S.E., ďComparison between Model Atmospheres and Spectra from Early-type Stars,Ē Annales díAstrophysique, Volume 27, p.781, February 1964] for a symposium, Astronomical Observations from Space Vehicles. This was help in Liťge. 17th Ė 20th August, 1964. Do you have any memory of that?
DeVorkin:What can you tell me about that? Did you go to Liťge?
Avrett:I think I did, and I think I presented the paper. But itís just a vague memory.
DeVorkin:Is it something that Steve actually did?
Avrett:Steve and I both contributed calculated results to the paper.
DeVorkin:Weíre looking at a reprint, ďComparison between Model Atmospheres and Spectra from Early-type StarsĒ by Avrett and Strom. And it says in the abstract, ďTo assist in the interpretation of ultraviolet continuum observations. We present observational features of the gray and non-gray model atmospheres in strict rate of equilibriumÖĒ Oh yes, hereís an interesting statement: ďWe consider the question of discrepancies between theory and observation in the ultraviolet from the viewpoint of these new calculations and find generally good agreement with recent observations by Ted Stecher.Ē Theodore Stecher. Now, heís at Goddard.
Avrett:That must be rocket spectra.
DeVorkin:Oh yes, that would be rocket spectra. Any memory of any of that?
Avrett:No. I do remember drawing the graphs. [Laughs] Thatís the only recollection I have of the paper, though.
DeVorkin:So this was not a big part of your life.
Avrett:I think I was just trying to be a good citizen and doing general solar and stellar atmospheres as well as pursuing the non-LTE line formation, which was my greater interest.
DeVorkin:Okay. Yes, reading from the paper, ďUVA observations are preliminary. Currently supplied by Ted Stecher in advance. Visual and new UV colors were obtained by Aller and associates,Ē so on and so forth. At the end of the paper, thereís no indication of credit given to a NASA contract or anything.
Avrett:No. This is prior to the Celescope launch.
DeVorkin:Oh yes, itís about four years earlier. But itís wonderful having this. Much appreciated. One would say that the connection to space is there with the reference in the abstract, but thereís nothing explicit going on.
DeVorkin:So thereís a little bit of patriotic work there.
DeVorkin:And you donít have any memory of anyone asking you to do this.
DeVorkin:How should I say you were drawn to this particular project?
Avrett:Strom was enthusiastic about it and I was delighted to collaborate with him. So I think that was the driver of this particular work. If he hadnít been here at that time, I probably would not have done this.
DeVorkin:I see. And his enthusiasm was for?
Avrett:He was very energetic; always has been. I think he understood the merits of the UV observations that might be available from Celescope, although this was never really discussed because it was in the future. We were just doing the best we could with data that was available at that time — Stecherís rocket data and so forth — and preparing the groundwork for further research in this field. Steve left in the late í60s to go to Stony Brook and Robert Kurucz carried on what Steve was doing with the model atmosphere calculations, but more from a systematic point of view. When the Celescope catalog was being devised, then we were in a position to help out by doing the companion volume. We were set up to do this sort of thing. It was the state-of-the-art model atmospheric calculations at that time in association with Celescope observations.
DeVorkin:Understood. I think that situates it very well for me to understand historically. Do you think it may make some sense for me to speak with Steve Strom? What about your other colleagues?
Avrett:Oh, yes. Steve can also give you some insights into the early development of optical astronomy at SAO and the building up of Mount Hopkins. He was one of the key people convincing Fred Whipple, ďLetís go for SAOís own ground-based observatory in Arizona and forget about Harvard.Ē That may have been contributing to the rift between Goldberg and Whipple because Goldberg was pushing a Harvard telescope in Chile and wanted the Smithsonian to join in with that effort. Fred, without probably discussing this with Leo, said, ďNo. Letís just do our own.Ē
DeVorkin:In collaboration with the University of Arizona, eventually.
Avrett:Yes. They chose to collaborate with Arizona rather than with Harvard, which might have annoyed Leo.
DeVorkin:Thatís something he definitely had to deal with. But the observatory there, of course, predates the MMT interest there. Dave Latham talked about even doing the site survey there. Are you saying, though, that Steve Stromís discussions with Whipple predate that even?
Avrett:I think so. Steve got his Ph.D. earlier than Latham did. I had the impression that Steve convinced Fred to do this.
DeVorkin:Okay. That would be good to follow up. That would be very helpful. Hopefully, he will come to the AAS meeting in January. Iím hoping to have plenty of tape available for people. Well, thatís an interesting clue, a really interesting clue. What about your other colleague, Kurucz. Heís still here?
Avrett:Yes. He was an undergraduate working with Steve Strom and then became a graduate student. Then Steve left and, I became Kuruczís advisor and saw his Ph.D. through.
DeVorkin:Would he have been closer to the Celescope Project?
Avrett:No. Iíve always been the intermediary. But he did the calculations for the Celescope companion volume.
Did you ever have to go to Washington to NASA to present at any review meetings or conferences?
Avrett:Yes, for one of the main briefings at NASA.
DeVorkin:I would like to receive a copy.
Avrett:Okay. Art Code and Fred Whipple were summoned to give a progress report to the head of NASA at that time.
DeVorkin:That would be James Fletcher, maybe? [Administrator, 1971-1977].
Avrett:It might have been an acting head. This was after the launch of Celescope because Code was presenting some real results and Fredís concern was that we didnít have many real results to present. Nevertheless, I was given the assignment to give a beautiful, 15-minute scientific talk to the head of NASA about the wonders of discovery in this area. [Laughs] I worked on that for more than a week.
DeVorkin:I definitely want to read it.
Avrett:Iíll find it. I pulled out all the books and was trying to say something about everything. Somebody said afterwards he made remarks that it was the only talk he understood. [Laughs]
DeVorkin:It wasnít an astronomer I take it, but somebody in the general NASA administration?
DeVorkin:So this was a formal meeting. You went to NASA headquarters in Washington, DC.
Avrett:And there was the administrator for NASA and all his people, with these two delegations, and there were two hours of talks.
DeVorkin:Do you recall if anybody asked you why there were no solid results or whether there could be solid results?
Avrett:Maybe that was explained and accepted. I donít know.
DeVorkin:Yes. Would it be in your text where you would say something like, ďWell, there hasnít been enough time yetĒ?
Avrett:I didnít say that. I just probably made some reference to that when all of this is done, itís going to reveal certain things.
DeVorkin:Okay. Well, thatís what Iíll be interested to read because this begs a question. In 1958 when astronomers were talking among themselves about ďWhat is the first thing that you want to get out of space as far as stellar astronomy is concerned?,Ē almost everyone, including Lawrence Aller, Goldberg and others at that time said, ďAn ultraviolet catalog.Ē Whipple picked up on this and he ran with it. Whipple says in his own oral history, which I can reveal since heís passed away, that Celescope took so long to get off the ground that by the time it flew and produced data, the data wasnít that useful, even if it was perfect data. Do you agree with that?
Avrett:Yes. I think thatís part of it. But I also think part of it was the original expectation that the data would have been of higher quality and the calibration would have gone more smoothly than it did.
DeVorkin:If all of that had happened and it was absolutely exemplary data, would that have made any difference in the í70s in astronomy?
Avrett:Probably not. This companion series of model atmospheres basically shows everything you could do with data like that, and itís not much.
DeVorkin:Even if it was perfect?
Avrett:Yes, because it gave only broad-band colors, and not more detailed spectra.
DeVorkin:Because the field had moved on? Is that a reasonable way to say that the sophistication of stellar atmospheres had moved on or the problems had been solved?
Avrett:Problems havenít been solved. I suppose there were observations in other fields that seemed more interesting than following up the unsettled questions about ultraviolet colors and things like this. I think interest was beginning to decline in the field of stellar atmospheres because there was greater interest in other fields, for which there were observations that clearly gave you interesting, exciting results because they were so new. This was just a continuation of an old field extending into the ultraviolet, and there were no great surprises, only incremental progress.
DeVorkin:Youíre filling in a picture.
DeVorkin:But I guess in 1958, when nobody knew what was out there, this was kind of a mapping. Would you agree with that?
Avrett:Thatís true in 1958. I think by the time Celescope flew, we had some rocket observations, could pretty well predict what we would see in the ultraviolet, and it wasnít that interesting. It was just a little bit more of the same that we were familiar with.
DeVorkin:Right. Charlotte Moore Sitterly was working through this time extending the tables to the ultraviolet at the NBS. Was there any cross-fertilization there, any contact with her or her group, with the multiplet tables? Did you need better multiplet tables? Were all of these things in hand?
Avrett:No, Kurucz picked up in that field and devoted his career toward spectral lines and their identifications and wavelengths, and has really carried that field on to a very high level of sophistication. Heís the primary person here calculating detailed spectra in LTE, and heís moved that field along and is recognized as the world expert in the calculation of solar and stellar spectra throughout the whole spectrum.
Weíve been talking quite a bit about Celescope, but during this period, you also had published using data from the OSO series, from the orbiting solar satellites. Iíd like to know a little background on that.
Avrett:Yes. Jorge Vernazza was one of the post-docs working with Leo Goldbergís Solar Satellite Project. For his Ph.D. thesis, he took the extreme ultraviolet continuum intensities at wavelengths between different lines [ďStructure of the Solar Chromosphere,Ē 1972 Harvard Ph.D. Dissertation]. The line spectrum is very complicated and one simpler aspect of the ultraviolet spectrum is to find patches of continuum between the lines. Itís a little bit easier to interpret theoretically. I became his thesis advisor, and he and I published a series of three papers based on this data and establishing models of the solar chromosphere on the basis of these observations. That was a very useful collaboration. In fact, those papers are still regarded as the standard models of the solar chromosphere.
DeVorkin:You were doing chromospheres in the í70s?
DeVorkin:Here it is. The first one is í75. ďFormation of the Solar EUV Spectrum.Ē [Avrett, Eugene H., ďFormation of the Solar EUV SpectrumĒ, Bulletin of the American Astronomical Society, Volume 7, p. 360, March 1975].
DeVorkin:Then ďThe Calculation of Theoretical Chromospheric Models and Predicted OSO 1 Spectra.Ē [Avrett, E.H., ďThe Calculation of Theoretical Chromospheric Models and Predicted OSO 1 Spectra.Ē Progress Report, 1 July 1974 - 31 December 1975, Smithsonian Astrophysical Observatory, Cambridge, MA, December 1975]. Thatís you alone again. Thatís a Smithsonian progress report.
Avrett:Yes. Sometimes I would go to meetings and make a presentation.
DeVorkin:Then there is ďThe Structure of the Solar Chromosphere Paper II: Underlying Photosphere and Temperature Minimum Region.Ē [Vernazz, J.E.; Avrett, E,H.; Loeser, R.; ďThe Structure of the Solar Chromosphere. II - Underlying Photosphere and Temperature-Minimum Region.Ē Astrophysical Journal Supplement Series, Volume 30, January 1976, p. 1-60]. Thatís Vernazza, Avrett, and Loeser.
Avrett:Right. And hereís a copy of paper number three.
DeVorkin:Sure. ďThe Structure of the Solar Chromosphere, III: Models of the EUV brightness components of the quiet-sun.Ē [Vernazz, J.E.; Avrett, E,H.; Loeser, R.; ďThe Structure of the Solar Chromosphere, III - Models of the EUV Brightness Components of the Quiet-sun.Ē , Astrophysical Journal Supplement Series, Volume 45, p. 635 Ė 725, April 1981]. If I go to another list, which is ordered in terms of your citations, that paper, ďStructure of the Solar Chromosphere IIIĒ, is your top-cited paper. You have almost 1,000 citations to it. How does that feel?
Avrett:Itís good. [Laughs] Iím writing a sequel that will completely replace that paper with something much better.
DeVorkin:So this is between í73 and then í76 and then í81, this series of three. So in a way, the OSO data were far more important to you in your career.
Avrett:Right. Oh, yes. If it hadnít been for that data, I probably would have pursued that line in any case with whatever data was available, but I did have an inside track to some of it.
DeVorkin:Yes. Well, thereís so much stuff youíve done. I mean, ďSolar Spectrum Synthesis,Ē [Kurucz, Robert L.; Avrett, Eugene H., ďSolar Spectrum Synthesis. I. A Sample Atlas from 224 to 300 nmĒ, SAO Special Report Number 391, 1981] is highly cited. ďThe Solar H and K Lines.Ē [Linsky, Jeffrey L.; Avrett, Eugene H., ďThe Solar H and K LinesĒ, Publications of the Astronomical Society of the Pacific, Volume 82, Number 485, p. 169, April 1970]. But then there was work on the extended chromospheres of other stars, like Betelgeuse, and then ďMass Loss from FU Orionis ObjectsĒ [Croswell, Ken; Hartmann, L.; and Avrett, E.H., ďMass Loss from FU Orionis ObjectsĒ, Astrophysical Journal, Part 1 (ISSN 0004-637X), Volume 312, p. 227 Ė 242, January 1, 1987] was highly cited. So really was the OSO data something that drove you into that area? Or were you getting more interested in that area yourself?
Avrett:I remember that shortly after I finished my thesis, I made the decision to write a comprehensive, general purpose computer program for stellar atmospheres calculations. I had all the equations and I knew exactly what was to be done. While I could have done some of it by hand very laboriously, I wanted this program for the computer. I went to Tillinghast, who was the Assistant Director for Administration and I said, ďI need a programmer.Ē He said, ďAll right,Ē and he assigned me an undergraduate, Rudolph Loeser, who needed part-time work and did programming, so he began working for me part time and that started this collaboration. I felt that we could do this general purpose thing because I had his programming services, and I could put in absolutely all the physics and with good mathematics, to simulate everything. After working together on several projects, we started our collaboration on the Pandora computer program in 1966 — I have all my program write-ups in this series of notebooks, and the earliest one is 1966.
DeVorkin:The black three-ring binders?
Avrett:Yes. Every week or two Iíd give him a formal set of instructions of changes in the program and I keep a copy, hence the series of notebooks. So from 1966 to the present heís been working with me on the same program. It includes many more detailed physical processes, at least for an atmosphere stratified in one dimension, than any other exiting program..
DeVorkin:Pierre DeMarque at Yale operates that way. He had a core program and kept building on it for stellar interiors. Is that a style these days? By ďthese daysĒ, I mean the last 30 years.
Avrett:Whatís my competition? My competition is younger, very bright guys who do all the programming themselves, and do some very sophisticated things that I find a little bit difficult to duplicate. But Iíve been building this thing for such a long time; there are more bells and whistles than theyíre ever going to get to. And the program can be applied to the sun, the stars, nebulae, quasars, but not 3D atmospheres. I collaborate with people doing stellar work as well as solar work. The program is fairly versatile. My current problem is that Rudy Loeser has been supported in a Federal position up until this year, but with the budget cuts, the director said, ďThis cannot go on any longer.Ē So he is now officially retired and is continuing, just on a retirement basis. I donít know how much longer. I can run the program, but I need him because I canít do the sophisticated programming to make changes or improvements.
DeVorkin:So he spent his entire career here then?
DeVorkin:And heís retired on federal retirement?
Avrett:Federal, so itís a generous federal stipend, but nevertheless, itís not quite what he was earning before. I have to get some outside money for him, so Iím working twice as hard trying to make the case to get some outside money to bring him up to the level that he was before.
DeVorkin:When did the belt-tightening begin here?
Avrett:Things have been pretty stable here as far as Iím concerned, up until just this last year.
DeVorkin:So, throughout your whole career here?
Avrett:Well, I havenít personally been affected.
DeVorkin:What about your programs, your ability to do research, to maintain your students, your assistants, that sort of thing.
Avrett:Thatís been pretty stable. There was a time when Fred Whipple had to make some staff cutbacks of permanent federal science positions that he had to eliminate so there were three or four people that had to leave. When George Field replaced Fred, he eliminated a few positions.
DeVorkin:Yes, one can expect that to happen. Do you remember what the situation was — did Whipple have to do any kind of retrenchment or RIF-ing [reduction in force]?
Avrett:Jim Wright, at the National Science Foundation as a fairly senior administrator, and was here on the staff then. His position was eliminated just because of lack of funds. So sometime, maybe the late Ď60s or early 70s, several people, including Jim Wright and Henry Mittler, had to be RIFed simply because the SAO budget was cut and it was unavoidable.
DeVorkin:Iíd be interested to know who they were so I could maybe find them.
Avrett:Jim Wright will, Iím sure, give you an earful. [Chuckles]
DeVorkin:Okay, yes. I think he lives in the Washington area, still?
Avrett:Yes, I think heís still with the NSF, or was a year or two ago.
DeVorkin:Yes, Iíll find out. Okay, thatís very interesting. Weíre moving toward the end, and I want to make sure we cover everything. Now, letís talk about teaching, what was the issue there?
Avrett:There were only a small number of Harvard professors in the Astronomy Department in the early 60ís and they didnít seem to take much interest in the graduate students at the time, who were then were gravitating toward Smithsonian advisors. I had five Ph.D. students during those years; it was the same for other Smithsonian people; whereas, the Harvard faculty was sort of ignored. Not entirely; Bill Liller had a lot of students, but Ed Lilly didnít. The astronomy faculty staff was very small, the Smithsonian staff was growing, and there was a fairly large student population. So, the Smithsonian staff took over a lot of the teaching responsibilities for the department, as lecturers.
DeVorkin:Were you aware of any kind of quid pro quo for that? Was there a payback from Harvard back to the Smithsonian for that?
DeVorkin:Not at all?
DeVorkin:Okay, so that became an issue, I imagine.
Avrett:That didnít bother anyone because we didnít have to do it; it was voluntary.
DeVorkin:Oh, it was voluntary. Itís something you wanted to do?
Avrett:Yes. Only the people who wanted to, did. I think there was a surprisingly large number of thesis supervisors during the Ď60s that were Smithsonian rather than Harvard.
DeVorkin:Youíre alerting me to this fact. Maybe I should do some statistics and see just what the split was to appreciate Smithsonianís role.
Avrett:Yes, not only in teaching of courses, but who was the thesis advisor of various theses. Youíll find that Smithsonian did a fairly heavy share of the department load in supervising and teaching graduate students.
DeVorkin:What were your favorite courses that you taught?
Avrett:Early on, I did some team teaching with Steve Strom and Cecilia Payne-Gaposchkin, mainly with Steve Strom. When Steve left, I didnít feel like I wanted to do that sort of thing all by myself, so it was somewhat later I taught the graduate stellar atmosphere course, and two times radiative processes in astrophysics. For more than a ten-year period, and then again for a three-year period, I conducted the undergraduate astronomy tutorial; so, I was in charge of the junior tutorial and administering the senior theses.
DeVorkin:You volunteered to do this?
DeVorkin:Did this have any influence on your decision to write Frontiers of Astrophysics? [Avrett, Eugene H., Frontiers of Astrophysics, Harvard University Press, Cambridge, Mass, 1976, 561 pages].
Avrett:Yes, exactly. In fact, youíll see in the preface what happened to be the readings that year, with a little bit of editing. [Chuckles]
DeVorkin:When people decide to do that, sometimes they do it out of frustration because they canít get the readings together for their students, or they canít get it in the proper overview, or somehow itís just a frustration; they want to have it ready. Others have different reasons. What was yours?
Avrett:It was a spur-of-the-moment thing. Iíd done the same thing of arranging a dozen or ten members of the faculty and Smithsonian staff to give a reading assignment or give a talk to the students covering all the different research areas that the students might be interested in. So I just decided at the beginning of the summer preceding the fall that, this year, weíre going to write a book. ďInstead of giving me a reading assignment, give me a draft of your chapter well in advance of your lecture.Ē
DeVorkin:And again, this was voluntary on your part and their part?
Avrett:Yes, there was no budget, no expenditures.
DeVorkin:Was there a publisher?
Avrett:Harvard University Press.
DeVorkin:So you knew that from the beginning?
Avrett:I contacted them. I said, ďWhat do you think of this?Ē and they said, ďFine, go with it.Ē
DeVorkin:Okay, so it wasnít as if you had the manuscript and then you started looking; you had it from the beginning. Good, okay.
Avrett:My ground rules were that the reading assignment given to the students prior to their lecture would be their chapter already written.
DeVorkin:Thatís very smart.
Avrett:Okay, I said. ďYou write the whole chapter, Iíll do one round of editing, then you revise it, and that will be the reading assignment. Weíll then get input from the students and then you can revise it again after your lecture.Ē They all at least drafted something beforehand, rather than give a lecture and not having anything written months later.
DeVorkin:Did the students know what you were doing?
DeVorkin:And what was the general reaction?
Avrett:They liked it. They were all thanked in the preface.
DeVorkin:Yes, I remember seeing it ages ago, saying, ďI donít know whatís going on here.Ē
Avrett:It worked. It was in the fall term, and a month later it was all finished, went to the press and published. Lyle Boyd was the copy editor, and she was excellent. In fact, I was amused by her style. She had little slips of paper — she would put little slips as markers, but she had a fountain pen with green ink, and she would take the authorís manuscript and she would just simply rewrite what she felt should be rewritten. She wouldnít point things to the author and say, ďClarify this.Ē She changed it; she made the decision of changing wording. But then the author would see this, and if the author wanted to do something else, then he could do that. She was very good at it.
DeVorkin:Sheís written or co-written and edited a lot of stuff. History too; itís mainly history stuff. You continued to use that book, I take it?
Avrett:We used that book the next year, and then I think the year after. I then thought,, ďWell, Iíve done my part,Ē and I handed it over to somebody else. In fact, I handed the course over to Bill Liller. I think they used the book for a while. But Iíve had people at meetings in Europe whoíve said, ďOh, youíre the author of that book.Ē They knew me from the book rather than from my research papers...
DeVorkin:Weíve gone pretty darn far and we are almost finished. Do you have any comments or general observations or things that we havenít covered?
Avrett:No. From what you see in that 1981 paper, Iíve continued that basic line of research. Iím now working on a successor to this that does the whole thing so much better, but this stands as what people use until I supply something better.
DeVorkin:Yes, understood. I noticed here — Iím just looking at it briefly — that you are using a lot of EUV data, and you used Harvard Skylab EUV data, and that again is from Leo Goldberg. So you must have had a lot of contact with Goldberg. Could you maybe just talk about the Goldberg-Whipple problem? Tell me about that.
Avrett:The staff had no problem here between the two directors, but Goldberg and Whipple had their own. Goldberg was in a situation as HCO director with rather limited funds. He had his own NASA contracts and so forth bringing in money, and his own research group, but thatís soft-money. But Fred Whipple had this flow of money from SI and federal positions, and thatís very different. I think Goldberg was a little bit jealous of that. There was very little consultation as SAO evolved and there were new staff positions and so forth. Fred declined to let Leo be a party in discussions of any of that. Fred was keeping SAO pretty separate, from his point of view.
DeVorkin:Was it the Southern Telescope project?
Avrett:Maybe that was part of it. The fact that Fred went ahead with Mount Hopkins and the collaboration with the University of Arizona may have been a great annoyance to Leo, and SAO not collaborating with Harvard in the Southern Telescope, maybe that was part of it. There was almost competition between the two of them in staff positions. The staff here, everybody got along with everybody else just beautifully and there was no problem, but there was a problem between the two directors.
DeVorkin:So the staff wasnít degrading as a community?
DeVorkin:But was Fred interested in Harvard positions?
Avrett:No, Fred didnít care about Harvard positions. Leo could do anything he wanted.
DeVorkin:Okay, but Leo wanted the Smithsonian positions.
Avrett:There has traditionally been an HCO Council that is supposed to consist of the professorial staff and certain Harvard research associates. Leo broadened that a bit to include some Smithsonian people. Andrea Dupree and I were added to the HCO Council. What Leo wanted the HCO Council, or the broader HCO Council to be, was to discuss joint scientific priorities. His complaint was that Fred would just sit there and would volunteer no information about Smithsonian. He was a Harvard professor, and he had his rights to say things about Harvard, but he was not going to volunteer any information about SAO.
DeVorkin:I see. I could see thereís a bit of tension there.
Avrett:Leo got a lot of information from everybody else, who were very free, and so he knew what was going on. But nevertheless, Fred didnít particularly want to share the SAO administration with Leo.
DeVorkin:Have you heard of ĒSHORTĒ, it was a round table (the RT is Round Table), Smithsonian Harvard Observatories Round Table, in í59, and Iíve not been able to find out anything about it. I found a folder about it, and Iím trying to get access to that folder in the archives.
Avrett:I never heard of it. Does Chuck Whitney know about it?
DeVorkin:No, I asked him about that. He remembered SHORT. He said, ďOh yes, it sounds familiar, but I donít remember a thing about it; I wasnít involved.Ē So far I havenít figured it out. What youíre saying is the Council sort of became a meeting of the two institutions in some formal way.
Avrett:Well, Leo made an attempt to do that, but it never worked because Fred would not yield any information. That was Leoís big complaint. I donít know whether Leo provoked this fight before or after he decided to leave for Kitt Peak, and whether Leo just wanted to make sure that Fred wouldnít be taking over the Harvard side. So there was this big review. Iím sure you can get information about it. See if you can find information in Fredís files about the review of the Harvard-Smithsonian relationship.
DeVorkin:Who headed that review?
Avrett:It was Dean Dunlop.
DeVorkin:So was it internal to Harvard-Smithsonian, or did they bring in professors from all over the place?
Avrett:It was Dean Dunlop and some other Harvard professors and some outside people who formed a small committee. They took testimony from about 20 Harvard and Smithsonian people, every member of the Harvard faculty, every senior member of SAO. They took all this testimony about, ďWhat do you think about the relationship, and what are the problems?Ē They digested all of that, and then they made a recommendation that it should be a single director.
DeVorkin:And thatís the origin of the Center for Astrophysics, basically, that we know it today?
Avrett:George Field was then designated as the HCO director and SAO director a year later; he would take both positions. The Center for Astrophysics was George Fieldís idea, thatís his creation, after he came.
DeVorkin:I can straighten this out as far as when Leo left and that sort of thing. He was interviewed extensively by the AIP and Iíll read that interview too, see if he says anything about all this.
Avrett:I donít think Fred Whipple had any ambition to take over and also become director of HCO. He was perfectly happy to have that run by somebody else.
DeVorkin:But Leo was worried.
Avrett:I think Leo was so frustrated with Fredís unwillingness to run this place jointly or with some coordination that he tried to set things up so that somebody else would come in and take the joint position and replace Fred. I think Leo was out to get Fred.
DeVorkin:Well, now, as far as big transitions are concerned, of course, Leo Goldberg coming in 1960, í61, something like that, with Menzel out; that was important. Back in 1952, when Harlow Shapley was retiring, they brought in J. Robert Oppenheimer to head a committee to figure out, first, what to do with the Harvard College Observatory, and then, only upon that decision, which was never completely clear, Oppenheimer then chaired a committee on the appointment of a new director. I do not yet know how Menzel was designated the acting director, but itís clear that the Harvard Corporation took this very seriously.[DeVorkin 2006 Harvard in Shapleyís Wake — Hoffleit Symposium] There were a lot of problems going on at that time, mainly with Shapley. But it was something where they took one of their own board members, the board of overseers. Oppenheimer was on the board of overseers. Thatís how he got tapped for this. It was a very tough time, and it was mainly fights between the senior people. In terms of big watersheds in the history of this placeÖ
Avrett:That was a bigger one.
DeVorkin:I think the biggest was Edward Pickering to Harlow Shapley. Whereas bringing Menzel in — Menzel actually was the architect for a lot of that, making it possible for Whipple to head SAO was an enormous change in this place, and in astronomy, too.
Avrett:Yes, Iíve understood that Menzel facilitated SAO coming here with Whipple as the director; he suggested Whipple.
DeVorkin:Yes, quite right, and that was very significant. Actually, what Iím looking for now are connections between Menzel and Leonard Carmichael. Iíve been looking between Whipple and Carmichael and found nothing, but now Iím going to start looking for Menzel and Carmichael, and hopefully Iíll find something. Anything else about this Goldberg/Whipple period?
Avrett:I think thatís about it. The staff had no problems and got along very well. The Smithsonian people, the Harvard people and the Department of Astronomy people, there werenít any conflicts there. In fact, a number of Smithsonian people had been given Harvard professorships, so everything was fine, except at the top.
DeVorkin:How did you feel with this watershed period coming in? Did you feel at all insecure about the future?
Avrett:Well, I remember saying in my testimony to this committee that it made sense to me for Harvard and Smithsonian to be here together; that if Smithsonian moved elsewhere, I might not move with SAO. Also, another big point is that with Smithsonian being here, many of the staff have come up through Harvard. Theyíve gotten their Ph.D.ís and theyíve gotten staff positions here. So there are quite a number of people who have a connection with Harvard because they came through graduate school here, and it might be unlikely that they would be staff members of SAO if SAO had been located in Washington, say. So theyíve grown.
DeVorkin:Anything else you would like to add?
Avrett:In 1973, Alex Dalgarno was appointed Letters Editor of the Astrophysical Journal, and he asked me to serve with him as Deputy Letters Editor. We both continued for the next 29 years. This was another voluntary position. Also, I served for 5 years as the CFA Associate Director for Solar, Stellar, and Planetary Sciences.
Thank you very much.
Carrier, C.F.; Avrett, E.H. "A Non-Gray Radiative-Transfer Problem," APJ 134, 469.
Avrett, E.H., "Particle Motion in the Equatorial Plane of a Dipole Magnetic Field", JGR 67, 53-58.