Harold Weaver - Session II

DeVorkin:

Dr. Weaver we were just talking about some interesting things, and you were mentioning the work of Bottlinger, possibly you could continue.

Weaver:

I was saying how much I appreciated his work and I thought he was a very imaginative and original worker in astronomy and that many of the things that had been attributed to Walter Baade in the way of stellar populations and so on, had really been thought of ahead of time, or had been worked or suggested by Bottlinger. I remember very well that at the time, it must have been a year or two before Baade came out with the story of the populations that Baade had been reading and thinking about some of Bottlinger’s work on populations. I do think that Bottlinger had preceded Baade in this in many ways and that Baade was building on what Bottlinger had already done. As I remember, Bottlinger had three populations the extremes of population I and II, and then an intermediate case.

DeVorkin:

He actually did identify them?

Weaver:

Yes and even some of the same stars, W Virginia for example appears in the Bottlinger work as I recall.

DeVorkin:

These are published?

Weaver:

OH yes, these are all published and they’re in the Berlin-Bablesberg publications There are several papers there that do this. I think that somehow Bottlinger has sort of faded from the memory of many people and it’s too bad because he does deserve in so many ways a more firm name in astronomy.

DeVorkin:

The Bottlinger diagram too?

Weaver:

Yes, the Hass-Bottlinger diagram. Hass use to write and complain if you didn’t call it the Hass-Bottlinger diagram because he claims he really thought of it first and published some paper on it. But it’s really the Bottlinger diagram.

DeVorkin:

That’s the way I’ve always heard it. Okay let’s begin our discussion where we left off a year ago with the year 1944-1945 and you’re at the Lawrence Radiation Laboratory, Berkeley. You are still engaged in war work and I’d be interested to know how did you get to Lawrence?

Weaver:

Oh, how I got to the radiation lab. I really don’t remember just now whether I had mentioned that. I had been in Cambridge and there as technical aide to the Optics Division of which Ted Dunham was the chief. And in that position I did a good deal of travelling, in fact about a third of the time I guess, something like that, I was going around the country visiting the projects in optics that this division had; arranging for service tests or assisting in arranging for service tests of new instruments.

DeVorkin:

In service, do you mean new instruments and how they would perform in the field?

Weaver:

Yes, really field tests and getting field tests of new equipment, finding contractors or visiting contractors who would have been making these new instruments that had been proposed. It was just sort of general optical research for war purposes and I certainly visited Berkeley on occasion during that period. I renewed my acquaintances herewith people in the Rad Lab and there was some suggestion that perhaps I would like to come and join in the work here. At first I didn’t do that, but finally I did leave the work at Cambridge and accepted the invitation to come to Berkeley and join in the work here. It seemed as though first it probably was a more important task than I was doing though I must say that I enjoyed the work I was doing because I met a very large number of people in science, a great many people I never would have met in any other way; people who were involved in optical things. At Eastman Kodak I came to know quite a few of them and Perkin Elmer and the various large companies that were then doing optical work.

DeVorkin:

Can you discuss your specific duties? What was it?

Weaver:

In optics?

DeVorkin:

In optics, yes.

Weaver:

I suppose Ted Dunham originally invited me to accept that position because I had done a fair amount of instrumental work involved with instrumentation and had also enjoyed it. I had made telescopes and done things, and I was a young Ph.D. that Ted Dunham knew and felt would be compatible with him in the work. He obviously was the chief, but the two of us sort of operated that section over the period of time that I was there.

DeVorkin:

Was there other astronomers involved in that section?

Weaver:

Well not in the section, no. There were several people in the division of optics that were in some sense had close contact but I’ll come to another in just a moment. Dick Lord in spectroscopy at M.I.T. was the division aide and we were often together because our offices were adjacent at M.I.T. — 6109 was the building number. But there were astronomers involved in, I don’t remember the exact technical name for it now, what I’d call it the overseer’s panel. Each one of these divisions or sections had a group of scientist who were assigned the task of overseeing the work. They formed the “board of directors” if you wish, wrong term but right idea. And there among them were McMath and Bowen and W.V. Houston the physicist. They were the ones that I remember quite clearly from that time. Bowen of course was always very very good about the optical concepts and designs and was certainly very helpful in many ways. And McMath had all kinds of “ins” beyond science so he was also very helpful in a great many ways. That was when I first came to know them as individuals and not just as names on papers and books and so on.

DeVorkin:

You came to Lawrence Radiation Lab, at that time C.D. Shane, I believe, was the personnel manager?

Weaver:

He was the personnel manager, yes, and it was of course he was the one who hired me.

DeVorkin:

I wanted to clear that up. Was he the contact that wanted you to come here?

Weaver:

Yes he was one of the principal ones at the time.

DeVorkin:

What were your duties at the Radiation Lab?

Weaver:

Well there were two sorts of things that I did. Although I didn’t work there terribly much, I think I was originally assigned to what, was called the Technical Information Division. And in part that was to prepare reports and to circulate information of a variety of kinds. But more than that really the division or the section to which I became attached in fact was sort of the theoretical physics section. I worked on a number of problems there in shaping magnetic fields and scattering of particles, and so on. I did a good deal of the experimental work in designing certain shapes of devices used in the Calutron; this is the mass-spectrograph, the mass separator that was used for the purification. This was really in the division of the theoretical physics section that I did most of the work. It was interesting. There were several astronomers or near astronomers involved in it. Lawrence Aller was in that section and we were often together. We had known each other as students here at Berkeley before that.

DeVorkin:

Dan Popper was here then?

Weaver:

Dan Popper was here. He was an operator at one of the instruments that is he actually operated one of the mass separators. They were just experimental ones here, they weren’t production devices. But he was actually in the operating crew. Lawrence Aller was in the theoretical physics section. Massey was the head of the group. Oliphant was often around and quite a few of the British group was here I came to know quite a few of them. I worked quite often with Oscar Bunmeman who was in the theoretical physics section and he’s now at Stanford in plasma physics.

DeVorkin:

What types of experiences do you think you gained during the war through this kind of work that helped to shape in your future studies in astronomy? Do you think there was an effect?

Weaver:

In the first part yes, I think, that the optics work I did. I think that that was very helpful and very useful to me because I came to know quite a good many scientists that otherwise I would not have known. I always felt perfectly at ease going to optical companies and dealing with engineers and so on. Perhaps that was already there because I enjoyed optics and enjoyed doing things like that. But I think that it was in a sense a very useful and helpful experience for me. I cannot say that for the experience at the Radiation Laboratory. I can’t say that I got anything. Again I feel that I got to know a lot of scientist’s from a good many places that I wouldn’t know otherwise. I have made some very good friends among them, some of the English physicists who were here and I’m glad I had that opportunity to work with the physics community in a closer way than I would have normally. But as to the work itself I think that it had a negative value because it stole time it took time. In fact I remember Lawrence Aller use to occasionally quote what he called the “Weaver Equivalence Principle” and it was that “a year in this place is equivalent to a year in the grave.” And it really was. I really hated the time away from astronomy and other things.

DeVorkin:

Okay then maybe we should return to it. How did you come to Lick Observatory after that because that was your first position after the war?

Weaver:

Yes, that was the first position. Well that developed immediately out of my contact with Shane. He had invited me to join the staff at Lick. I confess I was sort of torn. I think I would have enjoyed going to Mt Wilson actually. And I thought for a while that perhaps that would be where I would end up. But it was in fact at Lick Observatory which certainly had many opportunities, but I probably did a rather different kind of work than I would have if I had gone to Mt. Wilson.

DeVorkin:

Had you had an offer from Wilson?

Weaver:

It depends on who you listen to. That was just at the time that the directorship was changing and Ike Bowen was becoming the director and he hadn’t made up his mind what he was going to do. Adams had always said that there would be a position for me there and I think if he had been named director, there might well have been. In fact Bowen was very long in deciding what he was going to do and the sort of work that he thought the observatory should do was rather different from what I was doing. So I guess I didn’t fit into those plans at all.

DeVorkin:

Well there as certainly advantages there, there were telescopes almost in completion whereas at Lick there were telescopes just barely on the horizon.

Weaver:

Oh just barely on the horizon.

DeVorkin:

Did Shane talk to you about the proposed large telescopes?

Weaver:

Yes, as I recall that was very much in the wind and certainly Shane was a good one to push that forward particularly I think because of his experience in the university. He had a very good background of knowing how to do things within the university and also particularly through the radiation lab I think he gained a wider acquaintance and ability in that way. I think that was a big plus for him in administrative things. So I think it was quite clear he was going to push through a large telescope.

DeVorkin:

Well what were the conditions like when you got to the Observatory? I assume that you had moved up there completely?

Weaver:

No, that was not the case. In fact it was a rather awkward situation at the start. You see had not been on the Lick staff, he was professor of astronomy here on the campus.

DeVorkin:

He was chairman down here, yes.

Weaver:

Well, that sort of got traded around from one individual to another. But he certainly had served as a chairman. At the time as I remember Crawford was the chairman of the department. But that’s a position that’s simply traded around, at least after the days of Leaschner who was the permanent chairman.

DeVorkin:

What were the difficulties that you mentioned?

Weaver:

Well the problem was that this place [Berkeley] was getting to start up again, that is students were beginning to return. And the staff was shorthanded. So I was in fact loaned by Lick Observatory to the Berkeley campus to teach at the start. So I was here on the Berkeley campus doing some teaching.

DeVorkin:

I see, that explains why once or twice I’ve seen you listed as on the staffs of both Berkeley and Lick.

Weaver:

I was for a while in both. For a period I had a double appointment, but at the very first from the Radiation Lab I was appointed to the Lick staff, but on loan to Berkeley because Shane would normally have been here as a member of the department. So I was on loan to the Berkeley department to assist in the teaching. We lived in Berkeley and in fact there was a bit of overlap. I was still working at the Radiation Laboratory but the appointment had not yet gone through but they needed help here so I used to come down from the Rad Lab for an hour or so a day and tech a class here in astronomy and then go back So at the very first it was a very mixed up affair. I was in process of being appointed to Lick, I was still on the Rad Lab’s staff and I was teaching a course in astronomy. Maybe there were two courses, I don’t remember, maybe only one, here. So I was probably teaching either the course in astrophysics or the general course in astronomy for the majors or one of those things.

DeVorkin:

Shane had moved completely up to Lick then?

Weaver:

Yes he was completely away from the Berkeley campus.

DeVorkin:

So was it understood that you were here only until they were able replace Shane and to regain their teaching staff.

Weaver:

Yes and also they had a housing problem at Lick. There wasn’t a house immediately available and so we remained in Berkeley. It remained that way for several years, then finally a house did become available at Mt Hamilton and we moved there. At first the idea was that it would be just for a summer that our family would go to Lick. And then we stayed indefinitely until I left Lick and became a member of the Berkeley department. For a period then I was still appointed at Lick — that is that during this sort of overlap period I had a part of my salary from Lick and a part of my salary from Berkeley.

DeVorkin:

Were you here when Struve came or were you up at Lick?

Weaver:

That was ‘51 I guess. Struve had invited me to come to the Berkeley campus. We talked about it many times during his observing periods at Lick, so it must have been after his first year but it was in 1951 that we moved to Berkeley.

DeVorkin:

I’m interested in how the Berkeley department changed with Struve’s coming and how Struve did come here? Do you have any information on that even though you were not here?

Weaver:

Well, yes and no I do have information or at least I think I have. As I understood it at the time there had been some internal squabbles at Yerkes and it just wasn’t very good for Struve to stay there. I think there had been several different things that he was considering and the Berkeley job I think suited him in many ways. It had connections with Lick and he was given an opportunity to do what he wanted to do. So he accepted this job. It was a curious thing. The department did prosper under, him and I think it started to take off under Struve. There’s no’ question about that because Struve was such an influential and important astronomer. He brought a number of people here. And the place did prosper. It was a curious teaching arrangement.

DeVorkin:

What was that?

Weaver:

Struve never taught a graduate course or an advanced course the whole time he was here. He taught only “Astronomy I,” that is the popular lecture course which revolved around the articles that he wrote for Sky and Telescope. There was a complete connection between the two. I guess he used the articles in his classes and developed his classes and wrote the articles, and there was kind of a reciprocal relationship there. But he always maintained complete freedom of operation and never taught any classes other than that one. He attended the seminars, always participated and did things like that but was not involved in the teaching in any formal way at all. He certainly had some graduate students and he had a number of Ph.D. students, but no formal teaching things except for that big lecture course and he always gave all of them.

DeVorkin:

That’s interesting. Did it make it difficult on the teaching loads of the rest of the department here, especially the teaching of astrophysics?

Weaver:

Well in part it did. The way that it got organized finally as I remember those things (we could look them up in the catalog) Henyey taught the graduate astrophysics course, both stellar structure and stellar atmosphere’s. And I taught the undergraduate course in astrophysics which I had been teaching for a number of years anyway. And a lot of interesting people had gone through that.

DeVorkin:

Who were they?

Weaver:

Oh, Bob Kraft was a student there and we still talk about that occasionally. That was his first course in astrophysics.

DeVorkin:

What do you talk about with Kraft?

Weaver:

Oh (laughter) what went on and what we did and so on. In fact I recently turned up an old exam that Bob Kraft had taken there and he was an excellent student. And it was a darn good examination I must say. He wrote out everything and did a fine job. I wish I could see some good ones like that now.

DeVorkin:

I know that his position was quite interesting. He’d already been a teacher, he had a family.

Weaver:

Yes he did.

DeVorkin:

And he came back to school. Were you aware of this at the time he was going through?

Weaver:

Oh yes indeed. That was all entirely known. He was always and outstanding student and certainly deserves every honor and position that he’s obtained. He was first rate. Roger Lynd’s was in that course and Beverly Lynd’s and there were lots of students who have gone through including some of them here on the staff, Hyron Spinrad. All kinds of students scattered around the place.

DeVorkin:

Did you teach any galactic structure?

Weaver:

Yes. In fact that was the principal reason for coming. Trumpler’s position became available. He retired that year. And it was really to replace him that I came. And I did thereafter, up until recently, always teach the course in galactic structure.

DeVorkin:

Let me ask you now that we’re talking about that specific point how did the book by Trumpler and Weaver^[1] develop. When did it become evident that you were going to do such a monumental work?

Weaver:

Well, Trumpler had always wanted to do that. He had always talked about doing a book based on the course that he had developed over many years here in the Berkeley department. And toward the end of his career he definitely wanted to do that book, so he proposed that we do it together. And so we did. It was something that I thought I would enjoy doing. It was of course the field in which I specialized and it gave me a marvelous opportunity to think things through and put it together. So we planned it. It was obviously his book. He was the senior author absolutely. It was patterned largely in the way he wanted to do it; though when it came down to writing we really shared it very equally. We divided the chapters and then he did first drafts of one and I did first drafts of others. We sort of alternated one, two, one, and two. And then we’d exchange these things and argue and fight about them at length and finally we came down with what was there.

DeVorkin:

What kind of arguments did you have?

Weaver:

Oh there weren’t any very serious ones I say that factitiously. We never did argue or fight that way. The only point that ever came up was that suddenly it seemed to me that there was something entirely missing and I realized that never once in the book had solar motion been discussed. And so we had to do that and a few other things of this sort and we did argue in one or two places. I think that there’s a sloppy section that does not deal properly with least squares. And I do remember that we argued at length about that, about the order of which things should be presented. I’ve always been somewhat dissatisfied with that particular section which deals with a discussion of solar motion where I’ve never thought it really did it in exactly the right way. It’s not as rigorous as it should be. I wouldn’t mind doing another version of that sometime with someone. But I don’t know that it ever will be important.

DeVorkin:

How would you change it today?

Weaver:

Well in some ways it was as unfortunate a book as Unsold’s.^[2] It came out just before H and so the opacity is all wrong. And in 1951 our book in stellar statistics was written just before galactic spiral structure was discovered. So of course there isn’t anything of it in there. There are just some bland statements about the spirally of the galaxy and a little bit about the Gould Belt and whether this is an offshoot of a spiral arm or some little perturbation or whatever. But there isn’t anything about spiral structure, so of course there’s a whole major chapter of galactic structure that’s left out. And it’s not a very theoretical book obviously. It has a practical approach to things and I think that any modern book would be a lot more theoretical. Whether it would be more useful I’m not sure but at least it would be more theoretical.

DeVorkin:

Did you have contact with people engaged in theoretical studies of the galaxy at that time?

Weaver:

Yes to some extent of course, all the people working in the field. But it was not an aspect of it that ever attracted Trumpler that was definitely his book.

DeVorkin:

Was he satisfied with the book?

Weaver:

I think he was quite pleased with it. I think he felt it was culmination of his work in that field and that it did represent the kind of permanent statement of his view of the course.

DeVorkin:

And it was used here as a text, I imagine the following year?

Weaver:

Yes it was, though it was also supplemented. I did give a somewhat more theoretical course than is involved in there and I dealt with a number of topics always that weren’t mentioned in there. I very much enjoyed teaching that course and taught it for a long time. Then as the department grew, I seemed to have gotten tarred with a different brush, I was called a radio astronomer and so I was supposed to teach other things and others came who had interests in that. So in fact I have not taught anything in galactic structure except in seminars for a number of years now. I really sort of miss it. I feel sort of cheated not doing this anymore. But Frank Shu likes to teach it and I think he should.

DeVorkin:

But this is relatively recently.

Weaver:

That’s relatively recent and Ivan King teaches a part of it. So everybody sort of wants to get into the act.

DeVorkin:

Even though the publication and writing of the book was premature for spiral structure you had been engaged at that time doing color work, or at least producing refined HR diagrams using the MKK system and things like that. By 1953 you began working on B stars, O associations and spiral structure.^[3] Obviously you had been quite effected by the discovery and I would like to have your recollections how it came about, how you mapped out your own participation in the field.

Weaver:

In a way I guess that’s an interesting interlude. I can in fact trace it to the very hour that started me out on that. I guess it was in the IAU in Rome in 1952. Oort gave a very important review paper on spiral structure as determined from neutral hydrogen That was sort of the first important big disclosure of what had come in the way of spiral structure as a result of the 21 centimeter discovery which had been made a year before. And in fact Hank van de Hulst is here for a while, he’s been here for a couple of weeks. [Pause] I could trace my really extremely great interest in doing more in spiral structure to this very interesting, important and fundamental review that Oort gave at the IAU. I thought about it a great deal and in those days one didn’t travel by airplane very much by boat, so we had a trip across the Atlantic on a boat and I think we were there for five, six, seven, eight days something like that. I still remember sitting out on the boat, on the deck, planning all of the different ways that I would work on spiral structure when I got back. And the first thing of course was to look at the clusters and the distributions of clusters and the B stars and that was when that work originated. So I can trace the sort of inspiration to a specific talk at a specific place. That occupied me for several years thereafter. I think that there were some interesting things out of it.

DeVorkin:

Who did you talk to at the Rome meeting? Did you talk to Oort about what your participation might be, or to anybody else?

Weaver:

I probably did. I don’t remember talking to individuals about it as much as I do just thinking about it on the way home. And that was when it did develop. The two major things were of course this straightforward business of just getting a better set of numbers, a better set of distances for clusters. There was a paper on that.^[4] And one that I always thought was very nice and that was to treat the stars as molecules or atoms in a gas. And then to discuss the distribution of velocities of the early B stars in segments or sectors of longitude around the galactic equator and indeed one comes up with the same sort of picture that was found for neutral hydrogen. I don’t think that’s ever achieved any great popularity but I always thought it was a nice application and it does show the spiral structure beautifully of course. The same pattern in the “star” gas (treating them as individual atoms or molecules) and in the neutral hydrogen picture and somewhere there is a model published, a picture of that distribution compared to the distribution one would get if there were a uniform distribution of stars in the plane and obviously the uniform distribution does not fit and one can reproduce a very nice spiral pattern dealing with the distribution of stellar velocities

DeVorkin:

Was this basically an N-body study?

Weaver:

No, No. It wasn’t anything as sophisticated as that. It was just putting down the distribution of velocity in each 10 or 15 degree longitude strip and seeing that that is a multi-modal one — that there are various humps which correspond to concentrations at different distances of stars in those particular longitudes and therefore to continuous features or strings of stars which turn out to be the spiral arm.

DeVorkin:

During this period you must have begun getting very interested in radio astronomy.

Weaver:

Yes because it was obviously something that one needed to know about in order to do work in the galaxy. And so I did a lot of reading and a lot of thinking about how to use this new tool. And in fact in that particular time Struve’s importance inserted itself time and time again. He certainly was interested in radio astronomy and very early on invited Ron Bracewell to come for a year. Ron came and he gave a course in radio astronomy. He had just finished writing Radio Astronomy with Pawsey, and in fact I think he had the page proofs along with him or something like that and they were his lecture notes. So that also spurred people on at Berkeley to think about radio astronomy because we had a real live radio astronomer with us at that time. Another question initated by Struve was whether or not Berkeley should go into radio astronomy. He proposed to the university that this question be looked into, so the dean of the graduate division appointed a committee, the usual administrative method, to investigate the problem.

DeVorkin:

Who was on the committee?

Weaver:

I was the chairman of the committee, and the other two members were Louis Alvarez and Sam Silver. We spent quite a long time talking about what radio astronomy could do in all kinds of studies, and we finally arrived at the conclusion that “yes indeed if the University of California purported to be an up-to-the minute and important research place it had better get into radio astronomy.”

DeVorkin:

How were you chosen as chairman of the committee?

Weaver:

I really don’t know.

DeVorkin:

You were asked?

Weaver:

I was appointed. The university appointment letter says: “Please accept the appointment of this, that or the other, if you find that you cannot serve please reply or otherwise don’t bother me…” effectively. So I knew I was just the chairman of it. These letters are very curt.

DeVorkin:

Were there any people here who felt that radio astronomy was not the way to go?

Weaver:

No I don’t think so. I think it just required some sort of push and some sort of formal document to get into it.

DeVorkin:

No contact with Lick Observatory at all on this?

Weaver:

No and I don’t think they had any interest. In fact I don’t think they still do. They’re not interested in those things. They have their own problems. No I think they never had any interest. That’s perhaps cruel and I’ll modify it slightly. But let see, I was saying that we did decide that this place had to get into radio astronomy and we wondered what kind of radio astronomy, what should it do? Well there had been an idea or a lack rattling around, an idea that we lacked something here. This had rattled around for a long time in the Berkeley department. We never had any solar astronomy in this place. The nearest we ever got to having a specialist was Shane. Shane’s research was in solar work; work on line contours. He had a very nice large and powerful spectrograph that was used on the Sun. So he was in a sense a solar astronomer but he wasn’t terribly active in the field so there was a great worry that this place always lacked expertise in studying the Sun. So we thought that here was an opportunity to get two birds with one stone. We would go into radio astronomy and it would be solar radio astronomy. And we talked at length about who we might get and several people were proposed. In fact Bracewell was at one time invited but turned it down. And so the whole plan for going into radio astronomy languished for a period of time and finally Struve proposed that maybe I would agree to do it and I thought about it, but said obviously it was not going to be solar radio astronomy if I did it because we had talked about solar, this place should do. And so I agreed that if the whole idea of the field, the whole concept of what field of radio astronomy Berkeley would go into could he changed, that I would agree to do the job. And so Clark Kerr appointed me and established the laboratory. He had just then become president.

DeVorkin:

Right that was his first year.

Weaver:

That was in fact his first act. Whether it was Clark’s first or Sproul’s last I’m not quite sure. They were both very both interested in it. Clark Kerr was a great support. He was very favorably inclined toward astronomy and pushed this idea very hard and put the University’s word behind it and that was what finally helped us. So that was the start of radio astronomy at the place.

DeVorkin:

How large a facility did you envision? I would be interested to identify your funding sources and that sort of thing.

Weaver:

It was a long hard struggle for funding sources. The original plan was that the construction money would come from the outside that is the university could not supply the money for the telescope but the university agreed to supply half of the support. And we thought at that time of something in the beginning like $50,000 a year as I recall the number for operations and $25,000 would come from the university and $25,000 from somewhere or maybe it was 50 from the university and 50 from somewhere. We’d have to look up those, original numbers. But the plan was that there would be continuing operation paid for jointly by the university and some outside funding agency, and the outside funding agency would supply presumably the money for the telescope. Well we tried, I remember, many attempts at NSF and at the Office of Naval Research and I got quite adept at beating the paths around Washington looking for money, including some private foundations and so on, but without much help. Well the thing that really established the radio observatory was Sputnik. And when Sputnik went up and science became important and the Navy got’ money, the Navy started shoveling money into Berkeley for radio astronomy.

DeVorkin:

So this was still about a year before Kerr, Kerr was ‘58, Sputnik was ’57. Did you say it was’ an immediate effect of Sputnik, did it take a year or two?

Weaver:

No it was immediate. After the lab was established we didn’t have instant funding by any means and it was Sputnik that did it and the Navy at that time had the funds.

DeVorkin:

So you had searched for funds before 1958?

Weaver:

Yes I really should look up the dates of those things. They’re all easily accessible. But there was a long period of searching for funds and trying to establish it.

DeVorkin:

Okay that’s the important thing to identify.

Weaver:

Yes it was not an easy task and as I say I think we never would have succeeded in spite of all, the university’s good intentions if it had not been for Sputnik. And when Sputnik went up and the Navy had additional money they then immediately funded us. In fact I thought rather they funded us generously and they several times asked us if we couldn’t use more money. That was the only time that anything like that ever happened.

DeVorkin:

You were funded first by...?

Weaver:

ONR.

DeVorkin:

Later on within several years you began getting AFCRL money, but maybe we can talk about that later.

Weaver:

That was a sort of separate thing. That was really not radio astronomy that was just galactic research. That was under M’czaika at first, who was the head of that there. That’s a sort of separate story. That would be an interesting thing to explore sometime.

DeVorkin:

Okay let’s talk about the growth of the program in radio astronomy and then maybe we could talk about this because it involves your work published in a Lowell Observatory Bulletin, the work that you’d done on Cepheid variables and galactic structure.^[5] It sort of indicates to me that even though you were wholly involved in radio work you still were doing some optical work.

Weaver:

Yes, that certainly was right. I never got out of optical work completely. There was always some work in progress. Unfortunately I’m not a prolific publisher but I always had some optical work and I had several assistants and people working with me that kept some of the things going. They could do computing, Art for example, who just came in with that diagram now, Art has been with me helping in computing and so on for, “heavenly days”, it must be fifteen or twenty years.

DeVorkin:

What’s his full name?

Weaver:

Arthur F. Settiducatti.

DeVorkin:

The interesting thing about this is the fact that you continued optical work too, for the benefit of the tape, I’m looking at a, looks like a computer printout of synthesized radio map of the galactic plane, or something not too far from it.

Weaver:

It’s not too far, it’s between ten and fifty degrees and it’s centered on loops, on radial loops. Two and three for which I have a model now. And it shows that there were in fact two supernovae that exploded in that area and this is the little one that went off.

DeVorkin:

Well the interesting thing to me is that your generating resolution that is sufficient enough to give you a visual picture of what is going on. Is this very important to you in your research?

Weaver:

Very important, yes. I guess that I think more visually than numerically in that sense. I guess I think geometrically and visually because I always imagine things first as geometrical models which I can turn around in my mind and view from various ways and I very much need pictures generated by the computer to work with that. So I’ve long been involved in the generation of pictures from the hydrogen data or stellar data and so on.

DeVorkin:

It’s a remarkable picture. I can see the two loops you’re talking about.

Weaver:

Oh well I’ll have to show to some of the others, there are some really good ones.

DeVorkin:

Now at the time that you were developing the lab though computers were nowhere near present sophistication, so what were your hopes for the future, what did you see as an integrated unit of study?

Weaver:

Well I saw as an integrated unit of study a thorough investigation of galactic hydrogen I guess. And with as large a telescope as could be available, so the plan was that we pushed right up to what at that time was the limit of construction under anything but extraordinary circumstances — 85 feet — which was a fairly big telescope in those days. It was one that could be funded by the Office of Naval Research and that was the size that we planned.

DeVorkin:

That was the same size as Gold stone.

Weaver:

Yes that was the same size as the telescope that had been built at Greenbank too. That was an 85 foot telescope.

DeVorkin:

Were these standard designs that ONR was trying to encourage people to build or what?

Weaver:

At first I wanted to build a standard design and in fact what I wanted was a telescope that would have been a slight improvement over, but essentially the same as, the first 85-foot telescope at NRAO, at Greenbank. And it would have been by the same company, by Blau-Knox. They build the first 85-foot telescope. It was a somewhat ungainly design in some ways I think but it worked and I was trying to get as much as possible for the dollars available. I mean one doesn’t put dollars into un-useful things I think. But it finally proved to be impossible to get it, there was so much argument. There was really a terrible argument between the university Office of Contract and the Blau-Knox Company and they could not agree on guarantees, on design performance, on characteristics and this is one place certainly where the legal office just absolutely killed it off by delay, by all kinds of things and it was a very unhappy time for me. Finally we had to locate another source of supply and that was finally the Philco Corporation, Philco-Ford. This was a field the field of antenna design and building — in which they had had some experience, they had built some very nice smaller ones for Pt. Mugu, for various other places — rather elaborate and fancy designs — more than we required. They were anxious to get into it and so they gave us, I think a real bargain and we got the 85foot telescope, which has been very satisfactory, for a rather modest amount of money. My recollection is that it was $250,000 or something like that or even a little less. So we got it, but it did require a great deal of time, there was a long, long hiatus. I thought we should have been on the air and working when we were just starting to build because of this difficulty.

DeVorkin:

During this time in building up your staff what kind of decisions did you make regarding the types of staff. Did you want to hire astronomers who were electronic engineers, who could build and run and know what the astronomical needs were of the observatory, or did you want to create a very highly specialized technical staff? What was the philosophy?

Weaver:

The philosophy I would say was a mixture of what you said. We certainly had to have an engineering staff that we needed because we were in fact building these things ourselves. We did build one telescope. It was entirely engineered and built here, that was the 30-foot. It was considered, or at least I considered it a learning device. It was the instrument on which we were going to learn how to build things and how to install them when we had the big one. In fact in order to decrease the price of the 85-foot we agreed to do all the controls ourselves and so the 30-foot was a very important instrument on which we developed the controls, the setting mechanisms, the take-offs to give the readouts on the right ascension, declination, and the like. It’s a good thing we did do that because as it turns out not a single aspect of the controls on the 85-foot resembled the controls on the 30-foot, and we would have been in real trouble if we had put those original controls on the big one. So we learned a lot from that.

Weaver:

You asked what sort of development was planned for the observatory, and I said that at first we certainly needed an engineering and technical staff. The first developments were along that line. And so we had one engineer who came from Cal Tech and had been involved with the construction of their equipment, involved with the Cal Tech experiments. We had draftsmen and a second engineer in electronics. We needed to have people in the electronics field and I really looked very hard to find someone there. We had some reasonably competent help but more of a technician type. And the first combination radio astronomer and individual who could develop electronics was David Williams. He was the earliest sort of Ph.D. radio astronomer on the staff. Now I must say that I had tried to get a lot of other people too but it was very difficult and in fact essentially impossible to get anyone. At that time there was a development in the United States of the National Radio Astronomy Observatory, NRAO.

DeVorkin:

Struve had left by this time for the directorship of that?

Weaver:

Well no I think he hadn’t left yet. No he was still around. Struve was still here. We really should have a calendar that put these things out so that we get them all in sequence. No it’s very easy to get things reversed in sequence, that must be terrible for you in these historical things, and memory I think is notoriously bad in all this. No Struve was still here I remember.

DeVorkin:

We can always reconstruct the dates.

Weaver:

I’m probably a minority of one on this, but I think that NRAO, that the National Radial Astronomy Observatory in some ways started too early and held radio astronomy back in the United States. And the reason for this was that there were very few trained radio astronomers in the United States in those early days. There had been a few who had gone through Harvard with Bart Bok; those were Dave Heechen and Frank Drake and Ed Lilley and some others, Cam Wade and K. Menan; these were the individuals who had had an astronomical background because they went through a school of astronomy. They also had electronic backgrounds; they were instrumentally inclined in some ways all of them, they all were involved. Doc Ewen was a very important character in this in many ways. Well I think that those individuals should have been fanned out over the United States and been involved in universities where they would have propagated the faith and reproduced themselves as radio astronomers. In fact they did not because there was NRA0 and if you remember, Dave Heeschen was on the staff of NRAO and the first 85-foot exists because of what Dave Heeschen did. He insisted that they had to have some telescope to work with. He was a great power in just doing the right things in that place. And it was really through his instigation that that all got started.

DeVorkin:

Instead of waiting for the 140 or the 300 foot to be finished?

Weaver:

That’s right. Get something going because there wasn’t anything there. So that was a great step forward and I think it did a great deal to boost the morale. But the point is that that place was much more attractive to all of the radio astronomers and they all ended up, one way or another, at NRAO. And we offered jobs to all of them at one time or another here. We had nothing but blood, sweat and tears at this place or any other place starting up like this at a university because they certainly would have had some teaching duties here. We could have appointed them on pure research. We had a couple of positions like that. But if they had been full-fledged members of the department they would have been teaching in part and doing research in part. And I think that was, in many ways, less attractive to them than this other opportunity which promised the largest equipment and the greatest places and, so on. So in fact universities had a very difficult time getting started in those days because the young astronomers who had the proper training were attracted to a place that was pure research and doing all these things and not involved with the reproduction of other astronomers. And I think that that delayed the development of radio astronomy in a sense. There was a minimal grass roots push because the roots weren’t there; there were only a few individuals of an astronomical bent who were pushing radio astronomy in the universities as such. There was some work at Cal Tech. There was a Cal Tech group and there was a Berke1ey group and there was some work at Ohio State, but that was in the engineering department. John Kraus was really an engineer, he wasn’t an astronomer. It tended almost to be more engineering than astronomy.

DeVorkin:

Lloyd Swenson was at Illinois, but these were sporadic and were relatively small.

Weaver:

Yes, and from the engineering point of view rather than from the astronomical point of view. And so I do think that though it has an absolutely a marvelous record now and it’s just going great guns that in fact NRAO did sot of hold radio astronomy back for the first few years, because it wasn’t developing in the universities in an adequate way. I think we would have made more progress at a faster rate if some of these young radio astronomers had come into the Universities and inspired at a more rapid rate the students who were then in the field.

Weaver:

You know I’m not at all sure that others would share that view but I thought about it in the past a great many times and felt that it was important. And I suppose the reason I gathered this sort of view was that we tried so hard so many times to build up this place with that type of individual only to be turned down because it just wasn’t as bright an opportunity as existed there.

DeVorkin:

Well once you did get off the ground with staff and equipment, how did your relations maintain with the astronomy department? Were you part of the astronomy department?

Weaver:

No, I think there were tensions at times between the two. It was separate, it still is. It is a separate funded laboratory. It has its own budget. It has its own line items in the university budget. It has its own staff. And it is separate from the Department of Astronomy. It cannot teach. Laboratories of this sort are not permitted to teach in the University of California. The Department of Astronomy is the only teaching department. The laboratory can accept graduate students and provide them with facilities for research and give them advice, can aide them in the building of equipment, it can give them observing time, it can do all these things, but it cannot offer courses. It can only offer advice and research

DeVorkin:

If there was an undergraduate course in radio astronomy let’s say?

Weaver:

It would be taught by the Department of Astronomy.

DeVorkin:

Is there one?

Weaver:

There isn’t any, no. That’s sort of a separate item that I really should return to in a moment. Let me continue with this sort of separation of the two places. The goal for the laboratory was always to provide a service for the department. To be in a sense its research arm and to provide research opportunities of all kinds; assistance in making pictures and doing electronics, and all sorts of things for the department. It didn’t always work out that way. I think that the relationship of these two somewhat parallel organizations; associated very closely together in the same building on the same floor, intermingled, had certain tensions at times. But it has smoothed over and has become a very much of an integrated system at the present time.

DeVorkin:

When were there tensions? When did the tensions exist?

Weaver:

Well in the first year or two. In the first two years.

DeVorkin:

You’re talking about late ‘50’s, early ‘60’s?

Weaver:

Yes. And Struve rather, though he had favored this very much, worried about it and thought that it might take some power from him somehow.

DeVorkin:

You were all in the old Leuschner Observatory?

Weaver:

In the old place over there at the time.

DeVorkin:

That’s very interesting. It’s almost ironical because Struve went off to become the director of NRAO sometime in the early ‘60’sand yet he had these qualms.

Weaver:

He didn’t have qualms about radio astronomy. He had qualms about anything that he could envision as removing power from him. He was a very jealous sort of person in a lot of ways. And he tended to become very embittered toward the end of his life. I really do not know exactly why he always felt threatened, but he often did feel threatened quite obviously. He felt threatened when he was the director of NRAO.

DeVorkin:

Was he really the proper person to become the director of that?

Weaver:

No, no, not at all. It was done because there wasn’t any other solution. Soon thereafter, soon after he became director I did become a member of the Board of Trustees of AUI. And so I saw it from the inside administrative point of view. And Struve was totally the wrong person for that job in a great many ways. He had no knowledge of radio astronomy. And in fact he really wasn’t a very good person about instruments. He depended on somebody else to do something always. He would say: “go and design me this.” I still remember, to put it directly, the crazy recollection that has always stuck with me; When I first introduced Struve and the new engineer for the radio facility, Struve said “Well Mr. Larrabee it’s so good [Temple Larrabee] you’re here. Now just go off and build us a good radio telescope.” Just as though you leave it to this guy. Struve thought he could come in later and turn the key to start operating the radio telescope. Well things just don’t grow that way, you know it’s something you really worry through and sweat through and go through all the pains of hell to get an instrument that works. And you cannot rely upon somebody else to do it. Now that same sort of attitude on the part of Struve existed in the construction of the 140-foot telescope. And that went on and there were terribly difficult moments when Struve was director of NRAO because he insisted that he should have control of things. Whereas the telescope was obviously failing and was a miserable thing and Struve couldn’t have handled the problem. It finally went over to the engineering department at Brookhaven. And that’s the only reason there was anything that was sensible.

DeVorkin:

Who was responsible for making that major transition of responsibility?

Weaver:

The president of AUI.

DeVorkin:

Who was that at that time?

Weaver:

It was the guy who went on to become chairman of the Atomic Energy Commission and he became director of the National Science Foundation. He had been the Director at Brookhaven. It’s right on the tip of my tongue, the sounds are all coming in but there not coming in the right order. I can hear them. He was a very good guy in engineering, was a physicist. He knew all about the big machines at Brookhaven, had been involved in them, and they had a first rate engineering department. And they really took on the task of the 140-foot telescope. That’s the only reason in the world that it achieved the success that it did. There was a pile of junk lying around there at first.

DeVorkin:

You were on the advisory council of AUI.

Weaver:

On the Board of Directors.

DeVorkin:

Right. So you were privy to what was going on.

Weaver:

Hm mmm.

DeVorkin:

Now, how well known was this in the astronomical community, because I could see that a move like that, without knowing the circumstances, would create quite a bit of concern or fear of AUI and physics taking over NRAO.

Weaver:

I don’t think there was anything like that — that created any fear or had any repercussions of that sort. It was how the engineering would get done and would it get done by consultants or would it get done by some group? After all Associated Universities (AUI) ran both places and I think it was a rather sensible and normal way to do it. It wasn’t an abnormal thing, except I’m sure it was very galling to Struve personally.

DeVorkin:

Yes and that people would see it from that direction.

Weaver:

Yes, if he told about it and he tended to tell things rather freely.

DeVorkin:

During this period Lick Observatory was going through a major transition too. And I’m interested to know what if any you’re input as a member of the Berkeley group was with this.

Weaver:

You mean after I had come back to Berkeley after 1951?

DeVorkin:

In the early ‘60’s after Clark Kerr.

Weaver:

No, none. Lick Observatory was always a thing apart. There’s now much much closer relationship than there’s ever been. But Berkeley and Lick were never that close really. It was a great shame. But again there always were some kind of internal problems. They didn’t really interact at all in those years.

DeVorkin:

Well I was bringing that up because when you did do visual work such as with Cepheid variables, I assumed you did it at Lowell not at Lick.

Weaver:

Yes.

DeVorkin:

What was the reason for that?

Weaver:

Oh the reason was simply that there wasn’t any instrument that would have been available at Lick Observatory for the long period that was required. I had the Lowell telescope for a whole summer and more, one of the 20 inch telescopes. It was the telescope that Harold Johnson had been using for photometry. And it seemed rather reasonable to use that thing. Harold Johnson was one of my early Ph.D. students and so I knew him very well and that worked out alright. Again what I had gotten interested in was the Cepheid’s from the point of view of galactic structure; in the question of spiral arms and the distance scale in the galaxy and a variety of things of this sort. And I thought that I very much needed further information on the distances of them and that couldn’t be done without good photometry.

DeVorkin:

You wanted the whole light curve?

Weaver:

We did the whole light curve, and so we just started doing light curves for a large number of Cepheid variables. I would still like to return to some of those things if I ever live long enough to do it.

DeVorkin:

You became director of the radio group in ‘58, and you continued through the directorship till today.

Weaver:

Well I’m not director now.

DeVorkin:

Oh I see. When did that cease?

Weaver:

Oh about five years ago.

DeVorkin:

Oh I didn’t realize that.

Weaver:

Five or six years ago. I got awfully tired of the administration. I was just evaporating as a scientist and had no time for anything. It wasn’t the type of work that I had ever wanted to do, if I wanted to go into administration I think I wouldn’t have gone into astronomy. I would have gone into business somewhere and made my fortune instead of being a professor. I wanted to do the research and that was just not possible, in a way that I enjoyed. I couldn’t do the two together. And so I did resign as director and Jack Welsh is the director now.

DeVorkin:

I see. You maintained the professorship in astronomy?

Weaver:

Yes.

DeVorkin:

And you still maintain that to this dated.

Weaver:

Yes. And it’s very nice that I’m much freer to do research now.

DeVorkin:

Are you interested in getting back to optical work too?

Weaver:

Oh yes. Yes, in fact I have a small optical camera in process in the shop at the present time. I want to do some optical work and in fact I have been thinking, of all things, about returning to Lowell Observatory if I could, perhaps this year sometime. I want to talk to Art Hoag about it. It has to do with a combination of radio and optical work. I have been doing a lot of work in radio astronomy; the kinematics and dynamics of the local gas (local is within about 500 Parsecs), and very much need to know the distances of some stars that are involved in these structures of gas. And so I need to get spectral types and magnitudes and colors, etc., and it seemed to me that Lowell Observatory might offer opportunities to do this.

DeVorkin:

The opportunities are more sustained — because again you are not going to Lick?

Weaver:

It’s the sustained telescope time. I believe, and this is something that I have yet to determine, I believe that the Perkin 69-inch telescope (or maybe it grew to 70 or 71) there at Flagstaff would have a short focus camera with rather small dispersion spectrograph that could be used for spectral classification. And then the photometry either exists or could be done conceivably at Lick or Leuschner over the hill or someplace. I need to know for a few hundred stars all these standard statistical data and I just think that Lowe1 might be the p1ace. The old 36-inch would be very good but I’m not sure that the 36-inch at Lick has been used for such purposes in years.

DeVorkin:

Now you mean the refractor?

Weaver:

The refractor. It would he just splendid for these fairly bright stars, you know. There’s nothing beyond nine or ten and a lot of them at seven or eight.

DeVorkin:

Ninth or tenth magnitude might be getting a bit faint for that but seven or eight …

Weaver:

Seven and eight is easy, even nine and ten is not too bad. If it gets to be eleven and twelve, that’s really a terrible struggle. But the rest could come easily. And it has to do in fact with that object that you were looking at there a moment ago.

DeVorkin:

The supernova object.

Weaver:

That supernova object. I want to know how far away some of those gaseous features are, absolutely as surely as I can determine it and they will produce some extinction and some polarization and some other effects.

DeVorkin:

Have you made any attempt to recognize that event in ancient records?

Weaver:

I think it’s too old for that. But there is actually a crazy idea that I’ve had about it.

DeVorkin:

What’s that?

Weaver:

Well, it’s almost too crazy to discuss. The material on Velikovsky always comes through here you know, this Pensé thing that came out. And I sort of read that as an interesting sort of thing. There’s been recently some thinking (I probably have it badly garbled) that many of the truly ancient aspects of civilization with the cross and various symbols and so on, and the fact that northern direction was so involved (and there’s even one of the early gods associated in that way) was associated with a very bright object in the north. And this bright object was low enough so that the scintillation and other things would give these strange forms which later became symbols of one kind of another and stylized in a variety of ways. Now this supernova, which may have been one of them within, I don’t know, as much as 50,000 years or so, was in the north and it must have been a real whopper. It would have been as bright as the full moon. And. so it must have been a very attractive object and so I have wondered: “Is it just crazy, or is it real that there is some sort of very distant memory in the race of something terrible bright, funny, strange, queer up there in that northern direction?” And if that’s so then the two objects that I’ve been looking at up there certainly must be the objects.

DeVorkin:

There are two objects.

Weaver:

There have been two supernovas. One of them has produced a very strong perturbation in the gas. The other is a smaller object in angle in the sky. It’s a little bit farther away. And it must be a somewhat more recent one because it looks as though it has exploded inside of the bubble that the first one made.

DeVorkin:

Is there any kind of correlation between the two, one producing the other?

Weaver:

Well, again if one wants to be imaginative, yes. It was a double star. They come from the same group of stars, that’s clear, from the same association. It’s the Persei association. And if one wants to be somewhat imaginative here it was a double and the first one went off and the other by sling became a runaway star. And then sometime later it went off as a supernova too, so they may have been associated.

DeVorkin:

A violent event.

Weaver:

I’ll show you the pictures afterwards; you’d be interested in them.

DeVorkin:

We’ve covered a lot of material.

Weaver:

We’ve been really rambling.

DeVorkin:

We’ve covered a lot of ground. It’s been rambling, but it’s been centered on your radio work and we have covered parts of other aspects of your career. I’m not too sure exactly where to go on, maybe we should go back to the ’53, ‘54 period, and cover your optical work that we have not yet discussed. Does that sound appropriate to you?

Weaver:

Yes. What sorts of things would you be interested in?

DeVorkin:

Well how you came to different problems. You already reviewed that to a certain extent. Do you think there’s anything that we’ve missed? I’m interest mainly in the origins of ideas.

Weaver:

I guess that many of the things for a long period in there go back to this one unique event that so interested me and inspired me to work in a specific field and many of the other things grew out of that. There were the problems of the spiral arms, the problems of the kinematics of the galaxy, the Oort constants, which got me into all kinds of troubles.

DeVorkin:

I’m not aware of that.

Weaver:

Pardon.

DeVorkin:

I didn’t realize that you’d worked on the Oort constants.

Weaver:

Yes I did quite a long series, well not so terribly long, it may have been half a dozen papers or so — that’s long for me.

Weaver:

In part that’s why I was involved with the Cepheid’s also because I needed better and better distances to discuss this kinematics of the galaxy. The situation was that I began to come out with values that were very different from the ordinary; from the then accepted ones. The Oort A was 20 kilometers per sec or 19½ and the Oort B constant was about l0 sometimes a little bit more than that and so on. And these numbers, as I could find, from my own investigation just didn’t match up. And so I did several things related first to a kind of statistical survey, or statistical approach to what were the questions of mathematical bias in the way in which these were done. And the particular numerical values which depend very much on the distance scale after all it’s called “kilometers per sec per kilo parsec,” so if the kilo parsecs are of different lengths then the numbers are different. And there was a whole sequence of things of that sort that I had gotten involved in. And it got into lots of trouble. It got me into trouble with Oort, because he did not like the numbers that I came up with, my interpretation, and it took me a long time to get things into print with lots of referees going forth and back.

DeVorkin:

Did you have direct contact with Oort on this?

Weaver:

Yes. And he was rather cool and rather not very helpful at all on lots of these things.

DeVorkin:

Now this was basically a recalibration?

Weaver:

Yes, there were two things that I pointed out. The first was that there was mathematical bias. And I think my interpretation angered him, because I don’t think he interpreted the word mathematical bias in the mathematical sense, it may have been interpreted in the way of “he’s a biased man” which was not the case at all. It’s just that if you have a mathematical function and you approximate it, you linearize it, you will then normally get some sort of bias in the result when you use the linearized form. And so I wrote several papers^[6] dealing with this problem showing that in fact in the linearized form there is a double linearization of the problem and that the first linearization gives you a certain bias. The second linearization, which is the Oort formulation, provides you with a very severe bias that you can come out with quite wrong answers no matter how many precise numbers you put in. When you grind those numbers through you come out with a wrong answer. You’ll come out with the precise answer if you do it exactly in the way you should, which means the rigorous formula. But it was this other problem that caused some trouble. Then it came out with A=14 or A=13 or A=15. And these were very different so there were lots of trouble and lots of problems and so on. And then finally I guess the value was about l4½ that I finally got for A and B was 10 and R was 10 because I always insisted that the proper quantities had to go together. There’s a sequence of relationships that must be obeyed. You must have A-B is equal to W and R₀W₀ must equal V₀ etc. etc. And you’ve got to have these things all obeyed.

DeVorkin:

That would affect the size of the galaxy.

Weaver:

Indeed it did. And so the numbers that I had advocated were in fact the official values that had been adopted by the IAU since or very close. I think I had l4½ for A or something like that. Well those were officially adopted at one of the IAU meetings and the interesting thing is that though those were the numbers that I had been advocating for a long time I was not even invited to the Commission to discuss them when they were adopted.

DeVorkin:

Was Oort invited?

Weaver:

Oort had arranged it.

DeVorkin:

Unbelievable.

Weaver:

I shouldn’t say that for posterity.

DeVorkin:

Well it’s important. I mean you can have editorial control over it but it’s very important that something like that be understood in the future. They did come out and agree with your value but you’d not been given the way it’s been?

Weaver:

Well I think that’s correct. You know there are many sorts of, stones as sidelights of this kind that many astronomers can tell. In fact this point came up a few weeks ago at the Madison meeting of the American Astronomical Society. Martin Schwarzschild was there. I hadn’t seen Martin in a while so we were together at the picnic at the place. And Martin asked about this, somehow the point came up, because recently there been so much interest in the question of a big halo and the fact that the rotation curve is flat. This is related to this because you’re getting close to equality of A and B when you’re in a galaxy with a flat rotation curve, and it’s not very tilted at our point. On the other hand if A and B are ten and twenty this is essentially an inverse square. So in Oort’s galaxy we were in essentially Keplerian orbits and in the ones that the IAU adopted that I had been finding we were not in anywhere near Keplerian orbit and we were in a galaxy where the Keplerian orbits were still way way out, in other words a flat type of rotation curve. And Martin and I were discussing that again and he brought up that question and he was mentioning the fact that Oort didn’t like the numbers. And he said you know when he, Martin, did the thing on the Andromeda Galaxy, you remember that thing that he did on that, he said he had had terrible trouble with Oort and Oort really had lectured him quite properly about that paper which he, Oort, didn’t like. And again I think it has to do with this idea of the distribution of the mass and the character of the galaxy and other galaxies and there was one thing that Oort believed and it just wasn’t fitting in with the data that were coming out. And Oort is a very strong minded individual who will really lecture the person who comes up with these ideas.

DeVorkin:

When it has such strong consequences you would think that he would have the ability or someone like him would have the ability to see through the interpretations that were mathematical. And especially when the outcome is merely a better knowledge of nature.

Weaver:

Yes, yes, you’d think that wouldn’t you.

DeVorkin:

What is it?

Weaver:

Well I can only speculate, I don’t know. I think a person likes to see the numbers he has advocated vindicated, approved, and checked.

DeVorkin:

Now his constants have changed in value quite a bit over the years.

Weaver:

Oh yes.

DeVorkin:

But this was a different form of change, this was not changing the observation, this was changing the interpretation?

Weaver:

Well it was changing the numerical values and it was changing several things and one thing he said afterwards was that I came up with the right numbers for the wrong reasons. I’m sure he said that because I did not stress adequately the fact that the distance scale was involved. I always put this cycle of constants together as I mentioned to you and that involves the distance scale. But he said I hadn’t stressed it enough and that it was the distance scale that was changing, etc. etc. The interesting thing is that that is all coming up again, and we’re going to go through that trauma once more and not just in future. If R comes down to eight, eight and a half, nine, or whatever people want to make it, we’re still then in this problem of an inconsistent set of fundamental constants of the galaxy, the rotation constant, the distance scale and the velocity of rotation at this point. That whole problem is going to have to be thought out once more I hope, with a much better view of the galaxy and other galaxies than anyone had at the time the last squabble went on. And I think we’re going to have to learn that it’s not as simple a problem as it was. For example the things that Vera Rubin has been observing now in which there are distinct fluctuations within the spiral features in galaxies; the curve is flat way out, and it kind of undulates. That has to do somehow with the dynamics of the arms and the motions within the arms which are the bright objects that show up on the spectra. And I think we’d better think very carefully about all these things and not just bang off a set of numbers again which somehow ignore all the complexities within the arms, etc. etc. We just haven’t enough fundamental knowledge to specify and argue some of these features of the galaxies and of other galaxies at the present time. It’s a shame that somehow people get riled up and personalities have to assert themselves and so on.

DeVorkin:

But it’s a pretty common occurrence.

Weaver:

It’s a very common occurrence.

DeVorkin:

I’ve been at one or two meetings and I’ve seen people react quite visibly against the idea’ of the massive halo even though many people require the massive halo to sustain spiral structure.

Weaver:

Yes.

DeVorkin:

In the future what do you feel will be your directions of study of these problems. I mean you’re working on objects now in the radio range.

Weaver:

Discrete sources, but involved with the gas and its distribution, the interaction problems between stellar winds and the interstellar medium and supernova in the interstellar realm within an area surrounding the Sun big enough to provide a good sample of all of these things. There are a good many associations within a distance of 500 parsecs and there have been a good many supernovae in the past actually that can be traced out by the effects on the interstellar medium.

DeVorkin:

You feel then that this is a clue to some of the discontinuities that she had been seeing?

Weaver:

No, I don’t think that’s right. I don’t think in this information I have any clues to any of that. I think this will produce a very much more realistic view of what the gas is like, small hunks. Everyone wants to know the general source of the energy in the stellar medium, but I think here are direct indications of the interactive phenomena and how it goes, and the sorts of things that one sees. I can for example with this provide an overall view of why the sky in neutral hydrogen looks the way it does. Why we see what we see. Why there are all these arches and why there are certain motions, and the source of the intermediate and high velocity gas and all that sort of thing. It’s hopefully a kind of synthesis of the phenomena that have produced the radio sky as we see it around us. Not the large features in the galaxy, but just the radio sky we see cutting out the distant objects.

DeVorkin:

So you’re not looking for the origins of the magnetic fields in galaxies on the local scale trying to see if the highly charged shock fronts are producing these major loops that we see when you look at the whole maps?

Weaver:

Well I can explain those major loops. The pictures in back of you are scenes from a movie that we’re going to produce this summer.

DeVorkin:

Computer printout?

Weaver:

Computer printout. And the thing there on the left that you see is a tube of gas and then a supernova blows up, and you can see that star and you can see what it does. And those arches that result fit the arches that we see in the sky. And that’s the sort of thing. Yes there are really very simple explanations for all of the large scale features that we currently observe in the H1 sky, the hydrogen sky.

DeVorkin:

And a large part of them is supernova?

Weaver:

The large part. There are two sources. One is supernova remnants, or supernova explosions, and the second is stellar winds, particularly when there is a large group of stars — an association. And so you have all of the stellar winds adding up together and blowing bubbles. And in fact that’s a bubble blown by stellar winds, not a supernova.

DeVorkin:

Would you be able to determine the difference just in looking at the loop, whether it was caused by a supernova or stellar winds?

Weaver:

Yes. In this particular one there are no synchrotron radiation results that are its very calm and peaceful. One of the stars subsequently blew up in there; one of the members of the association and I think probably several, but one that’s very clear. And you can see the supernova remnant inside the bubble of gas. So it’s a multiple phenomenon in that sense, that these two sources are involved.

DeVorkin:

Will this movie be generally available.

Weaver:

Sure. In fact if it works out well I’ll show that in Washington next year. I’ve been invited to give one of those lectures at the Air and Space Museum at the Planetarium. They have monthly lectures and I give one in May of next year. And I want to use this movie.

DeVorkin:

In the moments we have left I would like to ask about popularization in astronomy. How do you feel about it and what has been your participation?

Weaver:

Oh, I feel that it is a very important thing and I’ve tried to foster it whenever I can. That’s one reason why I’ve taken a great interest in the Astronomical Society of the Pacific which I’ve been involved with very deeply for many years. I think it’s very important for astronomers to let the public know about astronomy and that is also why I’ve participated in other things — in lecture series. I’m on the board of Directors of “Science and Human Values” which is the group that organized the big popular lectures in San Francisco over quite a few years. The one on stellar evolution had been very popular and has two series going this summer. And here on the campus, several of us have been trying to improve the lower division elementary courses in astronomy that introduce astronomy to the freshmen and sophomores and all the none-majors in science.

DeVorkin:

How do you feel that they should be improved?

Weaver:

Well I think that they have to be interesting and given in an interesting way that will attract the students. I think you’ve asked a very deep question in saying how should they be improved. I think there are lots of different ways in which they could, be improved.

DeVorkin:

Are you implying that they be more rigorous or that they be more attractive. How do you see the role of mathematics, do you want to downplay it?

Weaver:

In these elementary courses in the ones that are for the arts majors I downplay mathematics very much. In fact I do not use a single equation, but I try to provide (I have over the past few years been practicing this as much as I cart) rigorous explanations of how things work. For example these students who have no equations, etc. can really tell you how stars evolve. And I think they understand the physics of it. It’s all done by explanation and reasoning as to how it works, the physical principles invo1ved, lots of arguing by analogy and so on. But no mathematics because I think it frightens them away. I think if I start writing mathematics they’ll disappear, and I think it’s important somehow to provide these students with a picture of the tremendously interesting and important work that astronomers are doing. They’re just providing new views of the universe; it’s terrible not to try to let the students know about that.

DeVorkin:

Except that there must be some point where you draw a line with using numbers, using mathematics. Can you describe the balance of forces in a star so that students can functionally use it without even using, let’s say, the inverse square law of gravity or something like that.

Weaver:

Depends I think there on what you mean by “so they can use it.”

DeVorkin:

Use it in understanding how a star would evolve in responses to the changing internal structure.

Weaver:

I think one can do it so that they have a feel for what is going on physically. That they have an intuitive feel at least for what is necessary to start thermonuclear reactions; that there must be a certain temperature which means that there must be a certain velocity of banging together of the particles, that it is temperature that generates the speed with which the particles move; if they don’t move fast enough they don’t bang together hard enough to enter into nuclear reaction, etc. etc. I think that they can have a good feel for what goes on without writing down all the equations.

DeVorkin:

Oh certainly without writing down the equations, but I’m thinking of the feel. You can stay away from numbers completely?

Weaver:

Pretty much so I think. They get use to numbers as to the sizes of things and so on but, and the ideas of temperature. I really have been amazed at how well they can give all this back to in examinations, showing that they have a real understanding of how some of these physical principles work .

DeVorkin:

So you do see a better response?

Weaver:

I see a very much better response and I think that the classes that I’ve been teaching have been responding better and better as I’ve learned how, perhaps, to explain it more simply and with terms and concepts that they can understand.

DeVorkin:

Five and ten years ago, let’s say just two random periods, did you use more mathematics in the elementary course.

Weaver:

Indeed very much more. And in fact, I’d better say who did it. I haven’t been teaching these elementary courses very long, only the last five, six years. Struve was the one who taught most of them and Struve’s idea was always to have numbers and rigor. I think for one thing that the students then would accept that and I do not see most of the students accepting it now.

DeVorkin:

Why?

Weaver:

I really do not know. I wish I knew the answer to that question.

DeVorkin:

But you’re willing to take the compromise situation and go with it?

Weaver:

Yes because I believe it is very important to try to provide a view of what these scientists are doing. And it doesn’t do you any good to provide that view to just a few students who would come if you use mathematics and if you require that approach. More students will get information if you provide it in a way that they will accept. So in that sense I am a compromiser. This is not for the students who go on in the sciences and do astronomy and so on. It’s for those students who are in bookkeeping and business administration and English and history and etc. etc.

DeVorkin:

What text are you using?

Weaver:

I’ve tried several and I like Jastrow and Thompson^[7] best. Also three of us were trying to write up a text in this way, to join the crowd of now more than 40 textbooks and I guess we will put it together sometime.

DeVorkin:

Who are the other two?

Weaver:

One is the science writer of the Chronicle and the other is Ed Duckworth who teaches at San Francisco City College and is involved in this lectures series. That’s how I came to know him. He’s a great popularize of science. And it turns out also that him and I both taught courses from the same direction. I was teaching from the outside in. I start with the big bang and let the universe develop. And Ed always did it that way too in his classes. Most of the people here do it the reverse, they start with the Earth and then you work out and then the last lecture you see the Universe. Well we see the universe, from the beginning and go from the outside in.

DeVorkin:

That is an unusual way to do it.

Weaver:

I find it very satisfactory. And I think that it works out quite well with the students. I think they can see that.

DeVorkin:

I can imagine that it would catch they’re interests.

Weaver:

It really starts. And how did it develop?

DeVorkin:

The last question that I’ll ask you is; looking back over your entire career, we’ve looked at changes. Changes in your career, changes in policy and all sorts of changes, but I would like to know what stays in your mind as the most satisfying thing that you’ve done in your career.

Weaver:

The most satisfying oh my goodness.

DeVorkin:

Want me to put in on pause while you think?

Weaver:

Put it on. Let’s start. I guess there are really two things perhaps from a purely personal point of view and maybe that’s what satisfaction means. It is gaining some understanding of how things work. I do think that some aspects of astronomy I understand quite well at least at the modern level of understanding, maybe a thousand years from now it will be better. But I think I understand some aspects of our galaxy and other galaxies and of how they work. And from another point of view perhaps the thing that is most satisfying is having had a role in starting some aspects of astronomy in this department and in this area of starting the Radio Astronomy Laboratory. These are sometimes both very unsatisfying and unpleasant things and that’s a different story.

DeVorkin:

That’s an interesting reply. I appreciate that very much. Thank you very much.

Weaver:

You’re welcome.