Oral History Transcript — Dr. William Baum
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Interview with Dr. William Baum
William Baum; January 14, 1997
ABSTRACT: This interview surveys Baum's career as a physicist at the Naval Research Laboratory (NRL) and astronomer at Mt. Wilson and Palomar Observatories. After sketching Baum's early life, the discussion concentrates on Baum's role in the development of spectroscopy research at NRL, specifically his work on the UV spectrum of the sun - including the first successful UV spectra of the sun. Aspects of his experience in experimentation with V-2s and Aerobees, and his thesis research on rockets at CALTECH (PhD, 1950, physics) are also explored. Additional topics discussed include: Optics Division, NRL; White Sands Proving Ground (NM); relationships with, and costs and descriptions of Baird Atomic; V-2 missile experiments, development and launch; meetings with Werner Von Braun; and contacts with R.W. Wood, J. Strong, Lyman, Stockbarger, and Tousey.
DeVorkin:This is a tape-recorded interview with Professor William Baum in the Westin Harbor Castle Hotel. The interviewer is David DeVorkin, and the auspices is the American Institute of Physics. We're meeting to talk briefly about your early experiences as a member of the American Astronomical Society. As we talked briefly yesterday at breakfast, my interest is to find out what your impressions were of the early Society and how the Society has changed, in your mind. Especially, I think we talked about parallel sessions and the concern that people had over the nature of parallel sessions. So I will just leave it to you.
Baum:Well, first, to put this into context, I went to the Mt. Wilson and Palomar Observatories straight out of the Physics Department at Caltech. So I didn't know the astronomers; I didn't know very much astronomy. That was in January 1950. So early on, I was anxious to go to scientific meetings and to get acquainted with colleagues and to learn something. The first astronomical meetings that I went to were in the early 1950s, and without looking up some records I'm not sure I can recite the precise facts, but at that time a typical meeting consisted of about a hundred people. We came to know most of them, or know who most of them were, so that there were relatively few people at those meetings that I had not met at a previous meeting. I remember, though, that probably about 1951, when first contemplating going to a meeting, I went to the director of the Mt. Wilson Observatory at that time, who was Ira Bowen, and said that I thought it would be useful if I could go to an Astronomical Society meeting. His reply was, simply, that he had no objection. He didn't say, "Why, yes, we'll contribute to the cost of your trip," or something of that sort, "Go ahead if you want to." [Laughter] I don't remember whether I did go to that particular meeting, but I certainly went to some subsequent meetings, and I gained very much from them.
DeVorkin:What do you feel was behind his equivocal nature about going to the meetings?
Baum:I don't know. He was a conservative person. At that time, I think, to put it in context, I don't think it was very common to fund trips to meetings or to pay for them. If people went, they did pay for them out of pocket, or at least largely out of pocket. Perhaps he, as director, might have felt that he could tap the institution for the support of the director's travel, but I don't think that it was too common to pay for trips of other staff.
DeVorkin:And he was also, of course, a physicist.
DeVorkin:Could it be that he still identified more with the American Physical Society, or saw the real work of the observatory getting the 200-inch fully operational? That was part of your work.
Baum:That was, of course, the reason that Bowen was taken on as director of the Mt. Wilson-Palomar organization in the late forties. They were eager to get Palomar up and running. Bowen's expertise was in optics and instrumentation; he was very, very good at that. He had done important astronomical work having to do with unknown — at that time — Nebular lines. But his real field was spectroscopy, and his real background was in physics. When I was a graduate student in the late forties, probably about 1949, he dropped into my office in the Physics Building at Caltech one day and asked me whether I might be interested in a job at the observatory. The reason that he was asking me was that I was involved with instrumentation and with photoelectric devices, and they were interested in developing photoelectric photometry for use at Palomar for going faint, and they thought maybe I could fit that niche at the observatory. So he was proposing to offer me a job at the observatory. I said, "Dr. Bowen, I don't know anything about astronomy. I took an elementary course one time. I'm interested in astronomy, but I'm just not familiar." He said, "Don't worry about it; I don't know any astronomy, either." [Laughter] But in fact, he knew a lot of astronomy. It turned out that I did take that position and developed the photoelectric photometry for use at Palomar. But I felt I had a lot of learning to do, and there were really two ways to learn, apart from just reading. One was to attend Astronomical Society meetings; the other was to go to lunch with the bunch from the observatory each day, which I did, and I gleaned a lot from that. So my astronomical education came from lunch and from meetings.
DeVorkin:So the meetings did perform an important part of your education.
Baum:Very much so. Yes, indeed.
DeVorkin:It naturally raises the questions, what are the values of having meetings like this, and have the functions of the meetings changed?
Baum:I think the value might differ from person to person. For someone today taking a degree in astronomy, and somebody having had all the courses that are given in graduate study in astronomy departments today, for such a person, I can imagine that attending a meeting is quite a different experience than my early attendance at Astronomical Society meetings. Those people who have had those courses come with a level of preparation that I did not have in astronomy.
DeVorkin:So they come with different purpose in mind, probably, today.
Baum:I think so. There's a more competitive atmosphere today. Each person is trying to present papers and establish his career, his niche in astronomy. At the time that I was going to early meetings, the atmosphere was a more relaxed one, somewhat more collegial in a certain sense, I think, and I didn't really have that feeling that I was in competition with anybody. Perhaps I was naive in that respect, but I didn't feel that.
DeVorkin:When did you give your first paper?
Baum:Again, I would have to look up some records to find out. But I remember that by 1953 I had a photoelectric system operating at Palomar in the pulse-counting mode, which was then a very new thing, and was able to go much fainter in measurement than we had been able to do with ordinary DC chart recording of the signal from a photoelectric photometer. And that meant that I was able to report new results that were of some interest, starting about 1953.
DeVorkin:Were you finding that you were corresponding or collaborating with other people who were developing photometric systems? I know that for a little while, Newton Lacey Pierce was trying to develop a pulse-counting system at Princeton, but it didn't get very far.
Baum:That's correct. I was aware of that program. I had almost no contact with it. I did have a little contact with Harold Johnson, who was periodically at Lowell. He was back and forth and had various jobs. A little contact, but not a great deal. In the end I was mostly on my own, really, doing my own thing and working out my own way of doing things, but I did get some help from some of my colleagues at Caltech who were involved in high-energy physics. They were involved in pulse counting; these were for recording the tracks made by high-energy particles in crystals. The pulses that they were dealing with were those that typically resulted from a number of electrons departing the photocathode from a single event; that is, a single flash in the crystal would produce a burst of electrons from the photocathode, which would be multiplied up in the dynode structure of the photomultiplier, and deliver a pulse which was distinctly above the ordinary noise of the photomultiplier. The astronomical problem is a little bit different. Single electrons are ejected from a photocathode due to the fraction of photons that succeed in ejecting anything. So I had to understand how to optimize the distinction between signal electrons and noise electrons, some of which even came from the photo cathode. So there was a technological jump there. There was a difference in what I was trying to do and what they were trying to do, as to the level of signal-to-noise, but there was a similar hardware technology that I could learn from.
DeVorkin:When you went to meetings, did you typically give talks about your pulse-counting techniques? I'd be curious if you found the meetings useful for furthering your techniques, or you found that people were mainly interested in hearing about the techniques.
Baum:I think that the Astronomical meeting papers had to do with work we were doing in globular clusters and some work that I did measuring the light of galaxies.
DeVorkin:So you would report mainly on your astronomical results.
Baum:That's correct. I was collaborating with [H.C.] Arp and [A.] Sandage a little bit, around 1952 and '53, just as these techniques were beginning to come on line; and later on with Harold Johnson and AI Hiltner, in addition to Sandage and Arp. We were applying faint photoelectric photometry to the stars of globular clusters, particularly trying to reach the main sequence of the globular cluster. I was also measuring the integrated light of galaxies and thought that I could make use of the light profiles of galaxies in clusters nearby, compared with similar profiles of galaxies in more distant clusters, to relate the distances of clusters relative to one another. I also started using a multicolor system, first with six colors and later with eight colors, to measure the redshift of clusters, and so those were the astronomical reports that were given at various meetings.
DeVorkin:I should ask, these are very much in tune with the types of research programs that Mt. Wilson-Palomar was undergoing at that time, under Baade, under Sandage.
Baum:That's correct. Right. Walter Baade was the one who was instrumental in getting us onto the globular clusters, I think. Arp and Sandage were graduate students when I first started in 1950. I was on the staff of the observatory, they were graduate students at Caltech, and they later came onto the staff, following me a couple of years, I don't remember exactly. Sandage was away for a year, I remember, at Princeton. But when he came back, he joined the staff, and soon afterward Arp was taken on board. So we were working together in various combinations on the globular clusters, but I was doing my own thing as far as the galaxy work was concerned.
DeVorkin:And that was your own personal research, but was it in context of extending the redshift?
Baum:That's what I was trying to do. Now, that really didn't materialize until about 1957 or so. I went to the IAU in 1958 and reported, among other things, on some of that work, on the use of the light of galaxies in various spectral bands, about eight bands, to try to use that as a technique for measuring stellar populations in those galaxies. Then and soon afterward for measuring red shifts as well, around 1960.
DeVorkin:Back to the AAS, then. You were continually going to meetings? Did you find that you were going to meetings regularly?
Baum:Not too frequently. If I remember correctly, the observatory did contribute to some of the costs, but it was sort of on an ad-hoc basis. It was not something to be assumed, and people didn't have grants. Today, nearly all of us have grants, and we tap our grants for our travel funds, but that was a modus operandi that didn't operate at the time.
DeVorkin:For you on the West Coast, was the ASP an important outlet, as well?
DeVorkin:How would you compare the meetings of the ASP and the AAS that you did attend early on?
Baum:At that time, the meetings of the Astronomical Society of the Pacific, the ASP, were more like a smaller copy of the AAS meeting than they are today. Today, they tend to center around a particular theme, a particular symposium-like theme, or one or more. There are programs for high school teachers and that sort of thing, and for the amateur members of the ASP. But it used to be much more just a scientific meeting resembling the American Astronomical Society meetings, but perhaps on a smaller scale. The early meetings of the American Astronomical Society — I can't remember just what year, but perhaps in the late 1950s or so — the number of people was beginning to increase, the number of papers was increasing. There was great concern about whether they could continue having only single sessions; that is, avoiding multiple sessions, parallel sessions. In the early fifties when there were only a hundred people coming and a typical session was one made up of papers that were individually allocated fifteen minutes, nominally ten minutes to talk and five minutes for questions, papers were all oral. There wasn't such a thing as a poster paper or a display paper.
DeVorkin:But there was definitely a time limit, though?
Baum:There was definitely a time limit, but people were rather casual about it. The sessions would run behind, and the person chairing the session would politely suggest that perhaps we should get on with the meeting, we were running a half-hour behind, that sort of thing.
DeVorkin:But these were all un-parallel, just single sessions?
Baum:Single sessions. But there was the feeling that as the sessions got longer and the number of papers increased, something had to be done; they had to either shorten presentations or they had to go to parallel sessions. The question was, well, which should we do? I remember some fairly heated discussions. I don't remember the details of the discussion, with the exception of a plea made by Martin Schwarzschild in which he vigorously stated that he thought that the American Astronomical Society would fragment and we would all lose touch with parts of our field if we went to multiple sessions, and that we must do everything possible to avoid that.
DeVorkin:Can you remember approximately when that was, or was it at a Council meeting? I
Baum:No, that was in a general business meeting of the Society. I just remember we were all sitting in a typical college lecture hall and debating this issue.'
DeVorkin:Do you remember any other comments at the time? Were there reactions for or against? Who was making a compelling argument for the multiple sessions, or shorter papers?
Baum:I don't recall. I just remember that those were the issues and that the discussion was fairly vigorous. I won't say heated, but at least there was serious concern that we were in a position where something had to change.
DeVorkin:How did you feel about it?
Baum:I think I would have favored multiple sessions, which ultimately we did go to. I don't remember how soon after that particular meeting multiple sessions actually did take place.
DeVorkin:Did you go to American Physical Society meetings at this time, and did they have multiple sessions? 1Schwarzchild called for a quota system at the Princeton AAS meeting, April 1955.
Baum:I did not. I had attended a meeting or two of the American Optical Society, but that was, I think, before I took the position at Mt. Wilson. I think that was while I was still associated with the Naval Research Laboratory or still in graduate-student status.
DeVorkin:We have covered, generally, the things we talked about yesterday, but has anything since then come to mind that you feel is significant about the nature of the Society, the place of the Society in the discipline, something that you feel should be said about the Society at its centenary?
Baum:I could remark, perhaps, that the use of display papers is very recent. That's something that perhaps others have already spoken with you about. My first impression of them was that I was not eager to present display papers. I felt somehow I could communicate better with a reasonably well-prepared oral presentation, with slides and diagrams, and with an opportunity to field questions. I've come around to thinking that display papers are a good thing and perhaps the only solution to the very large meetings that occur today, but I had to be converted by seeing it. I didn't instinctively think that was a way to go. There was something a little bit off-putting by presenting results in that way, to my instinct. Today, I happily present display papers, and I understand that that's what we have to do and that this is an effective way to go.
DeVorkin:How about the structure of the Society, the fact that there is a vigorous executive office that now is based in Washington and very proactive?
Baum:I think it has to be that way, partly because so many people in the Society are deriving their funding from federal sources. There are policy concerns, there are concerns about recent graduates finding jobs. The Society can play a role that it never played during the earlier years — earlier for me, at least — that we've been talking about.
DeVorkin:Do you feel the Society has been proactive in anticipating these needs, or has it been dragged along, in responding to these pressures?
Baum:I don't think I have a comment on that. I happen to know Peter Boyce very well. Peter was at the Lowell Observatory and took the position with the Society in this regard. There were other people who had been working in that role before him, but I have been very much impressed with what I think was a good job on his part during the years that he carried the ball. The Astronomy Society transformed itself a great deal during that time period, not necessarily because of Peter alone, but because of decisions made by the Council and his implementation of them.
DeVorkin:Do you feel, if we were to point to one or two presidents of the Society who made a big difference over the past half-century, or at least the time that you have been involved in the Society, would you be able to name people and why they were significant?
Baum:I don't think that I had my mind turning on those issues at the time, and I don't think I could really point to some particular people. Probably there are one or two who should be cited as important, but I don't think I can speak to that.
DeVorkin:Any other thoughts at this time?
Baum:No, I don't think so.
DeVorkin:Well, this is a good start, and as we agreed, I hope, I will transcribe this, probably not edit it much at this time, but send it to you as quickly as I can. This will be for purposes of your crafting a one- or two- page statement, three pages, or whatever you think is needed, that we could use in our reminiscences section on the impressions in the Society, by a senior member in the Society. Does that sound fine to you?
Baum:Fine with me, and I'm sorry that my memory is fuzzy on some of the details.
DeVorkin:Well, as you said, you are willing to go back and look at some of your records, and to the extent that you can do that, it would be great.
Baum:That's perhaps an over-brave signal on my part, whether I can find the records I'm talking about or thinking of, but I think I may have some things. I tend to squirrel away a lot of old stuff. I may be able to find something.
DeVorkin:One final question. I know that you took pictures at White Sands.
DeVorkin:Did you continue to take photographs at Astronomical meetings, and do you have any of those pictures?
Baum:No, I didn't. I didn't carry on that habit of taking a camera with me.
DeVorkin:Too bad. [Laughter]
Baum:There might have been exceptions to that, but I just don't remember offhand. I don't think of having a collection of pictures anywhere. I wouldn't know where to look for them if I have them.
Baum:You can contact me in Seattle. I should explain, perhaps, that I do most of my work at home. I have runs of journals, and all that.
Baum:I am a research professor at the university; I go in to the campus about three times a week. I have a graduate student that I work with. But the number given is my home telephone, the fax is right behind my desk at home. And the e-mail address, although it's through the university, is one that I log into every day.
DeVorkin:Where should I mail stuff to you?
Baum:At my home address is best, and that's 2124 NE Park Road, Seattle, WA, 98105. I also have a mailbox at the department, but I may not see it for a couple of days, or certainly not across a weekend. So I think the home address is the best one to use, particularly since when my funds will run out, I'll go into emeritus status as far as the university's concerned. I'll probably be able to maintain a mailbox and an e-mail account, but my connection with the department will become an emeritus one, instead of an active member of the staff.
Well, thanks so much.