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Oral History Transcript — Dr. Robert Leighton

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Interview with Dr. Robert Leighton
By David DeVorkin
At Downs Laboratory, Cal Tech, California
August 5, 1977

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Robert Leighton; August 5, 1977

ABSTRACT: Topics discussed include: early schooling in Los Angeles; family background; interests in mechanical design and new techniques; Los Angeles Astronomical Society; schooling at Los Angeles City College and Caltech; early career choices; changes of interest; medical van de Graaff project; experiences at Caltech during World War II; interests and work in rocketry; engineering courses at Caltech; Carl Anderson and development of interest in particle physics and cosmic rays; development of interests in planetary and solar astronomy; access to Mt. Wilson. Students, colleagues and funding at Caltech; work on solar cycle; research philosophy and choice of projects; Mariner and other space projects; ground-based astronomy; support patterns in astronomy; Kitt Peak; relationship of Hale Observatories and Caltech.

Transcript

Session I | Session II

DeVorkin:

This is a second session with Dr. Robert Leighton, Friday, August 5th, and we are beginning to take up your postwar work in cosmic ray research here at Cal Tech with Dr. Carl Anderson. If I recall from last time, we had reviewed that Dr. Anderson literally had asked you to join this. Is that correct?

Leighton:

That's right. I worked with him during the war on the rocket launcher activities. I don't know what else there was about it, other than the fact that I was a graduate student and I guess he thought I was doing all right, and so I was there, and he needed someone else at the research fellow level in his cosmic ray work. I think my first appointment was as his research fellow. I’ve forgotten that now. It was shortly, in any case, in a year or so, that I was an assistant professor. lI’ve really forgotten. You can look that up in the official record.

DeVorkin:

The date for assistant professor for you is 1949.

Leighton:

Yes. I think I got my degree in ‘47.

DeVorkin:

‘47, that's right.

Leighton:

So I guess there were a couple of years as a research fellow in there. Well, I explained I think last time that I had complained to Carl that I didn’t really understand anything about cosmic rays, and he said, "Well, don’t worry about that, nobody else does either." And it was about that same time that the new particles were discovered by Rochester and Butler in England, and it was an exciting time. I guess really, up to that time, I guess the full import of all that didn't immediately make itself felt. But before that, there was the question of the nature of the meson. We called them "mesotrons" at that time. I guess Cal Tech was the only place they were called mesotrons. But the question of the decay products of what we now call the muon was a point of considerable interest. And then, the general nature of the penetrating showers, the nucleonic component of the penetrating showers, was also a hot issue in cosmic rays. That was also high energy physics at the time, because as you know, the machines were up in hundreds of MeV, and eventually soon, right around in there, were producing pions—pion beams, and discovering the [pi0 handwritten] and many other things. But I think at the time I started working with cosmic rays, the pion was not yet discovered. It was discovered within a year or so. ‘47, wasn't that the pion discovery time?

DeVorkin:

I think so, but I’m fuzzy on the actual names of the particles as they evolved. I know the names have changed. Later on, you worked on a V particle?

Leighton:

Yes. That’s something else. That's right. The muon was called the mesotron, at the time.

DeVorkin:

Yes, that's the confusion.

Leighton:

It was thought in some places, or many places, to be the Yukawa particle, the nuclear glue particle. Then Powell and company discovered another meson, that decayed into the muon, with a neutrino—a two body decay. And the pion clearly had a strong nucleonic interaction. It was clearly a strongly interacting particle. The problem with the muon was that it had the right mass, an intermediate mass particle to have the right range for the nuclear forces, but it didn't interact with nucleii. And people couldn't understand that. There were a lot of possible hypotheses that you could make.

Anyway, the nature of the decay products, of the muon, was a point of some importance, because it was still possible that it was the Yukawa particle.

So I think the first experiment that I was really involved with was in building our own cloud chambers at the time I built a cloud chamber for the specific purpose of trying to catch as many stopping mesons as possible—atmospheric, cosmic ray mesons, slow mesons in the atmosphere. And we made that cloud chamber. You showed me a picture in the GRIFFITH OBSERVER there. That's the magnet and the cloud chamber that I remember building for the purpose. (GRIFFITH OBSERVER, July 1950) It's what we call a falling cloud chamber. The chamber would expand, and then drop down out of the magnet gap. The purpose of that was to get a large volume' inside the chamber, in a fairly uniform magnetic field. If you look through the pole piece, you had an inhomogeneous magnetic field. We had a fairly uniform field. And then, it was thought that during the free fall, of two or three feet, that the convection currents which normally distorted the tracks would not be acting. The convection would start from the expansion, mainly because of temperature changes near the wall. We thought it would be a more stable kind of a cloud chamber. It might have been, but we had some technical problems, and we never quite realized our expectations and hopes, although it was very good for the particular purpose we used it for.

DeVorkin:

As you expanded the chamber, did you have trouble with maintaining or creating the drop in pressure?

Leighton:

No, it had two glass walls, two plane, circular glass walls, and we simply used the piston to push against one wall and compress it, and when it expanded, that piston moved back out of the way, and the wall came against a stop. Then it was a fixed-volume chamber, and just fell down out of the narrow hole in the air gap, and down some ways. There was an oil dash pot, which stopped it gently at the bottom and then it went back up by compressed air, like a hydraulic lift. But the mechanical aspects weren’t the important thing. The important point of that experiment, the important technical aspect, was that we put one of the Geiger counters right inside the cloud chamber. We had a copper plate, I think, if I recall, or aluminum perhaps it was, and then we had right next to that plate, a very flat thin Geiger counter, which would occupy a large solid angle, for things stopping in the plate. I forget exactly how we triggered it, but it was based upon the notion of a heavily ionizing stopping particle that went into the plate, but didn’t get out of the plate, followed by a lightly ionizing particle, within a few microseconds, after we opened up a gate and waited for a while. So we effectively selected out, preferentially, the stopping mesons. I remember, we got 34 of them![1]

DeVorkin:

34 counts.

Leighton:

Something like that. But this idea of putting the Geiger counter inside the cloud chamber was, I think, the key. There were a lot of other people, three or four other groups, who were hard at work, trying to find the decay spectrum, and you'd hear a report that they had a case in MIT and a case in Indiana and so on. And people thought for a while there were two discrete energies for the decay electrons. It was a 20 MEV one and a 60 MEV or something like that. And I think it1s true that the 35 cases or so that we got, 34 cases, gave us enough of a handle on the spectrum that it showed the characteristics that one would expect of a three body decay. And that essentially closed the problem. It didn1t provide a precise definition of the mass or anything like that, because we didn1t get the upper limit, but I thought qualitatively, it did define it as a three body decay, and so we immediately suggested an electron and two neutrinos.[2] Now, that idea, for putting the Geiger counter inside the cloud chamber, was Carl Anderson's. And I think it's fair to say that virtually every fundamental good idea we had, for some years in there—when Dr. Bud Cowan and I were here at Cal Tech, he and I were young people on the staff—basically went back to Carl. Of course, held done a lot of thinking about this. He had good insight and good intuition and everything. He certainly provided good guidance for the group. Strangely, he did very little actual laboratory work himself. But that was the beginning of sponsored research, you know, and there was the ONR, and there were proposals to write and reports to write, and things like that—and God bless him, he did that, and we young ones didn't have to worry about it. He got the money. It wasn't much in those days, but it was adequate to keep us going, and that was something I only later came to really appreciate.

DeVorkin:

I was going to ask you that, because it was acknowledged, it was joint sponsorship of ONR and the AEC.

Leighton:

That's possible.

DeVorkin:

This was a very early application of their funds.

Leighton:

Yes. I hadn't realized that, but undoubtedly that might be right, yes.

DeVorkin:

What you say is, of course, that Dr. Anderson had the contacts.

Leighton:

That's right.

DeVorkin:

So he wrote the grants. But I’d like to know how did he consult with you? Did he consult with you, let's say, in writing up the description of the project? Or was this a sort of exploratory thing? Was this cloud chamber built under the project, or did this exist before you came?

Leighton:

I built that. Not quite with my own hands, but almost, you know. It was big shop stuff, everything like that.

DeVorkin:

Did you have to have the design in mind?

Leighton:

No.

DeVorkin:

And do a whole budget analysis?

Leighton:

No! No, that's the beauty of those days, you know. The agencies had the sense to select good investigators, people who had some proven record, track record, or who had promise or something like that. Students that I know of, good groups, also were supported. But they didn't ask for exactly what they were going to do, or anything like that. One proposed to work in a certain field of research, using certain methods. But it was not specifically stated. Now, actually, I suppose one has to give credit also to some of the later agencies now. Generally one does not have to describe in detail a particular experiment, at least in the fields in which live worked. But the general approach, and some general plan has to be stated. And, of course, there's always the budget. If you're going to buy a lot of equipment, or build a lot of equipment, then you have to be very specific with cost estimates and so on.

DeVorkin:

All of this is done within the Cal Tech campus.

Leighton:

Yes. That's right. Shop work and all.

DeVorkin:

So as far as the budget was concerned, that was all internally determined thing?

Leighton:

Well, I really don't know the answer to that. I was so far from it, and I just didn't ask any questions. We would propose to Carl to do something, and he would say whether he thought it was a good idea or not, and if it was a good idea, we bought the material. Of course, all the purchase stuff went through him, at least the major things. We had a secretary, and we’d take things to her. But I'm sure that she immediately got his signature on it. So he knew what was going on.

DeVorkin:

As you mentioned high energy physics was all combined at the time, particle physics, and here we have an early interest of the AEC, in a rather important period of the time centering on the Cold War period.

Leighton:

Right.

DeVorkin:

I'm wondering if there were justifications? Was there any cloak of secrecy?

Leighton:

Oh, no secrecy whatever. No. No secrecy whatever. As a matter of fact, I think it was specifically a policy of ONR that it was quite OK for things to be published, and it was expected. As a matter of fact, for our reports, I think a copy or a reprint of published articles was considered OK. So there was no pressure from anybody to do anything secret. I don't know what would have happened if we'd had something that really was qualified to be secret. That is, if there was such a thing as a "meson bomb" or something like that. But I don't know what would have happened if there had been anything like atomic energy or nuclear fission or something like that involved. But at least in the things we were (involved in), there was no inkling of any possible need for secrecy, and there was no suggestion we worry about it.

DeVorkin:

Certainly there were tremendous gaps in understanding all processes of fusion, and astronomers did know, at that time at least, that there had to be another source of fusion that they still didn't understand, beyond proton-proton and CNO.

Leighton:

—that's right—

DeVorkin:

Had you ever had any inkling, or had anybody ever talked to you about the possibility that through some of this work, you would find that missing particle that would fit some sort of a fusion reaction better?

Leighton:

I don't think so. I think that we, and our sponsors, agreed that we were investigating fundamental processes, but with what ultimate goal in view, and with what possible utility, these were not a primary concern. The fact that it was fundamental research was satisfactory, certainly satisfactory to us because that's what we wanted to do, and it was satisfactory to ONR and the AEC because they also had seen in recent years that what appears to be fundamental and useless often is useful, in different hands or at different times or with enough understanding. And so, I don't think anybody was trying to get a bomb, or anything like that. I think they were genuinely appreciative that additional, increased understanding of fundamental science was a worthwhile endeavor for mankind, for US interests, and that the contact with the scientists, the knowledge put into circulation and understood, was a sufficient output. I don't think any of us felt either apologetic or obliged to justify our work.

DeVorkin:

Did you ever take flights of fancy and wonder yourself about the unknown processes in stars, from a purely intellectual level, at that time?

Leighton:

I was vaguely aware of the carbon cycle, and I have to say that in many of the things I've done, in hindsight—I guess it's true for everybody, but I feel it very keenly—I realized what questions should have been in my mind. Not specifically, but what attitude, really, I think. And I guess maybe this is partly why I'm not in particle physics now, high energy particle physics. I didn't ever have a feel for it, not in a purely theoretical sense so much as in a kind of pattern, a kind of an organizational sense, in terms of the possible qualitative quantum properties of particles—namely, the idea of particle schemes and so forth. I guess maybe nobody really had that idea, but certainly, the things that were motivating R. Feynman and the questions that he asked, only later struck me as being, not exactly obvious, but the right kind of things that I should have been able to think of for myself. But somehow or other, I wasn't able to. I couldn't see the forest for the trees.

DeVorkin:

Is there a possibility that you may not have been looking for these synthesizing elements because Dr. Anderson had immediately said, "Well, don't worry, no one else knows anything anyway." Was there that sort of attitude: well, we must observe and collect a certain degree of data, before we can really ever settle anything about questions of fundamental particles? Was that his philosophy?

Leighton:

I don't know. In retrospect, I think some of the items that went through our conversation, Cowan and Anderson and I, and Feynman and anybody else who was around, were really very close to things which, if we had realized their truth, and could pick them out of all the possible choices, all the confusion, you know, would have provided a very good guide for a later systematic investigation. And things could have gone much straighter. But that's the way knowledge is, I guess. It always is a random walk. That's good, because you go into byways you wouldn't have thought of, and so maybe you would miss a lot of things. But, for example, the notion that these V particles that we then came to study were, in some sense, excited states of a nucleon, because they decayed into a proton and a pion, we found out soon, and maybe they were excited states of a nucleon, and we already had an example of an unstable state of a nucleon, the neutron, and so maybe there were other ones. And that you'll find in one of the papers. I think Carl Anderson wanted to be sure that got in there. Whether it was like an excited state—and sure, that's a good way to look at some of the things. But it is not simply a random spectrum of baryonic particle masses we find these days. They have other quantum properties: the spin and the strangeness and the isotropic spin and so forth, are the classifying agents. But that idea, I never had. Somehow, I guess I regarded it as being too empirical a thing. My own view of it was driven by empirical things. That is, here were these things, never mind why they're there, they're there, let's find out about them. One can study their properties. But the notion of a synthesizing idea, I just—it never gripped me well enough for me to really do anything as a result. And maybe that's a failure. As I say, I'm probably just not the kind of a person who could do that.

DeVorkin:

Isn't it possible, though, that that reflects the state of the discipline at that time? Even now? People are getting very excited about whole new classes of particles, and charm, and that sort of thing. It seems to be just, not from the skeptical standpoint, because I'm not knowledgeable enough to be skeptical, but it seems to be an extremely empirical groping.

Leighton:

Oh, no. No. That's not the view I have. Maybe I'm far enough from it now. I see nothing but beauty in the particle schemes that I've been hearing about lately, with the supergravity, and now, these new quarks. I don't know in detail how they're supposed to fit in, but I understand roughly the classification scheme. I've got to learn more about it so I feel more at home with it. How the symmetries define groups of particles, and once you decide on a symmetry scheme and see how things fit in, you can then predict the possible other ones that are there. And it provides a good guide, for people to search.

DeVorkin:

You can see the guide presently, but at the time you were working, the guide was not there?

Leighton:

Yes. That’s right. I think that’s a good way to put it. That’s a good way to put it, the systematics were not there. They came very closely afterwards, with M. Gell-Mann and the idea of strangeness.

DeVorkin:

Well, you used that term, of course, quite early, the degree of strangeness, at least.

Leighton:

Yes. Well, but that was only after Gell-Mann had introduced it.

DeVorkin:

There were some other terms and particles which you and the team you were involved with were working with. But the important thing is that you seem always to have been involved with new types of machinery, for detecting decayed particles and things like this. You mentioned that Carl Anderson always had the good ideas. Is this really true, or did you?

Leighton:

He had one very bad idea, which fortunately we never followed up on. This is about the time of the nuclear emulsion particle work, you know—and he thought that there would be some virtue in making what he called a “micro cloud chamber.” Since his whole background was with cloud chambers, he thought he would do it with cloud chambers, you know. He wanted to make little micro cloud chambers. And I think, from what we now know and what we sort of had the feeling then, that just wouldn't have been a very good kind of a detector. The other kinds: scintillation detectors and later the spark chambers. The spark chamber probably was the real breakthrough, in making present day physics possible. You can select, on line, your [targets] and you keep a picture if it looks as if it's going to be interesting. We had to take thousands of pictures, to get 30 or 40 good cases of things. And they still have to, in some experiments. But that whole scanning mode of things, that was very much a way of life. I think probably he had a bad idea there. We never followed along on it.

DeVorkin:

How come? Did you know, or did you intuitively sense that this particular idea was not right?

Leighton:

Well, nobody picked it up. And as I say, he didn't do anything in the lab, and wasn't about to go build his own cloud chamber and everything. He's such a gentle person, so he could never say, "Hey, you guys, we've gotta build that little cloud chamber." We had a lot of things, good interesting things to do. We weren't looking for new ideas particularly. But I do remember, he kept mentioning it, that idea, and I always thought, it just wasn't a very good idea. I didn't ever really argue with him.

DeVorkin:

Now, you'd classify the early, through the mid-fifties, as a period that you were working primarily in particle physics?

Leighton:

I’d say so. Yes. There were some little excursions in other directions, with planetary photography and things like that. You were mentioning about the gadgets and the machines and so forth. There is another thing I learned from Carl in all this. He said once, probably more than once, that if anybody ever devised a new way to look at any particular phenomenon, or found a way to measure it ten times more accurately, he was sure to discover something interesting. And you know, I found that to be true, in the things that I've done, more often than not. I've found that getting an idea needed being interested in something. You have to start with an interest. It doesn't ever come just out of the blue. Then you get an idea of how to measure the thing, or how to look at it, or how to make the thing more efficient, say, in searching through pictures or something like that. If we made a way to do that, we could have found rarer events, and maybe found more—made our counters more selective, or something like that. But that is always a good payoff. I guess it is that we were still in an exploratory stage, and we were, in particle physics, at that time, and in certain other things that live become involved with, in exploring the planets and the sun, the solar cycle and stuff like that. There's little enough known about it that almost any new idea that you get has some chance of being interesting.

DeVorkin:

But you need the funding, and the energy, to carry them out.

Leighton:

That's right.

DeVorkin:

Was there any filtering process that Dr. Anderson went through, let's say in the various different types of projects, that you would tackle?

Leighton:

Well, I think research was sufficiently inexpensive, in those days. We did a lot of it ourselves, in terms of physical construction. I’ve always liked to do that, and once you get so you live that way, well, things happen fast enough that it isn't a waste of time, because I think a person who knows what he's doing—I don't mean he's better, say, at machine work or electronics or something—but knows what he can get away with, and what he needs, and can go five or ten times as fast as making drawings and hiring engineers and getting it built in the shop and everything. It won't be as nice a device, but it will work or not work so much sooner that you can be off on something else, or making the next improved model. And so it really pays to be able to do things yourself. And I've always valued that. I’ve always liked to do it.

DeVorkin:

In a way, those years seem to be much more individualistic, more bootstrap, than let's say the present day situation, where you have very, very highly competitive localized centers for studying high energy problems. Could this have been something in the fifties that you saw coming, that ultimately it was going to be just a very few centers that were very, very expensive, and the whole manner of research was going to be different?

Leighton:

I think we saw it in the high energy accelerators, sooner than other places. I think really it was a combination, wasn't it, of the natural tendency of machines to get larger in size, especially things like the high energy accelerators, and more expensive, but also, there was then another thing, and that was the tremendous growth of the enterprise, physics, and particularly astronomy. I think then that nobody saw that there would have to be, not just two or three more big telescopes, but ten or twenty big telescopes. The space effort, of course, did a lot of that too, by acting as a sponge or sink for astronomy students and physicists, people with some kind of technical background, who could really do things—they had a place to go. They were needed, in the space effort, all of a sudden, where they had not been really needed before. It was hard to find jobs in astronomy, for example. Then, all of a sudden, they needed all you can produce and “we want more.” You know. Well, a lot of colleges that didn't have much of an astronomy program suddenly started to get an astronomy program. And of course, there was a big bidding up for PhD students, and fresh degree holders, who would go to become head of the department at some place, and so the thing mushroomed. And we all know about the 17 percent a year, or whatever it was, that physics and astronomy were growing, at the time. The budget leveled off and there were great screams and things. It just had to be, because otherwise, by now we'd all be physicists.

DeVorkin:

I’m very interested in trying to identify the possibility that you were aware of this happening quicker, in the field that you were engaged in at that time.

Leighton:

You mean, so that I would change my field?

DeVorkin:

Well, it's a possible feeling. Yes. Because things were changing tremendously.

Leighton:

Well, I’ve always been interested in a lot of things. And I guess the specific question is: why did I change out of particle physics, when it seemed to be such a good thing and we had had some success?

DeVorkin:

Well, you had the successes, just about as much as anybody, from the observational standpoint, I imagine. But was it such a good thing? It seemed to be in a state of, not as bad as chaos, but there weren't these guidelines you were talking about.

Leighton:

Well, in a way, that makes it more interesting. I remember admiring the work of Dahlitz and people who were making statistical studies of things. They had enough cases. They would collect cases from all the places, and plot them on these diagrams, and find out where the points lay, and everything like that, and find what the phase space properties were, and all that was very nice. And there were a lot of particles. There were a lot of new things around. It was chaotic. I guess my own personal feeling was that I saw that the energies of machines were coming up to the level where they would soon be producing kaons and so forth. And I somehow couldn't visualize— I knew I was going to have to move somewhere else, to do work, research at a distant center, and with a big team. It looked like a kind of a scientific life that I just wasn't cut out for. And so I just opted to do something else. I went upstream (in the cosmic ray stream), up to the sun. But that was a personal decision. I think that, at the time, I could have easily moved over into machine studies. And I just looked at it, and decided that it wasn't really what I wanted to do. So I didn’t do it.

DeVorkin:

That's interesting. Well, you mentioned these excursions into planetary astronomy, and I do remember the color time-lapse motion pictures that you had generated of major planets. Was this from the mid-fifties actually?

Leighton:

Actually, 1950 was the first.

DeVorkin:

That early?

Leighton:

Yes. You see, we were building these cloud chamber units, and we got a new idea: we'd build a great big one down at Bridge Lab, here at Cal Tech, at about that time, ‘54, ‘55, I forget, but in the late forties and early fifties we were very active in that. But we realized that to study these strange particles, we could get much richer beams if we went to higher altitudes—so, making portable cloud chambers, airplane-mounted cloud chambers. As a matter of fact, they had the B-29 project, which is partly why Carl needed somebody else, when I first went to work with him, at the time. The B-29 cloud chamber was his old positron cloud chamber, adopted for the big airplane. And except for the fact that they hooked it up wrong, it could have been a real pioneering instrument. They looked at the electron showers. But they didn't look for penetrating showers. If they'd looked for the nucleonic component, in the airplane, they would have just gotten a fantastic output. And with what reward, nobody knows, because the opportunity went. They had three B-29's and they lost two of them in accidents, and I don't know, I guess eventually they didn't fly them any more, for scientific use. But about that same time, we were taking these cloud chambers to mountain sites. The falling cloud chamber was put on a trailer, and taken up to White Mountain.

DeVorkin:

Yes, I remember.

Leighton:

To ten or eleven thousand feet, I forget what it was. And we then brought it back from White Mountain. We lost a student, you may know.

DeVorkin:

No. I didn't know that.

Leighton:

Oh yes, an undergraduate who worked with us during the summer was killed in an automobile accident up at Big Pine, somewhat in connection with that. They'd taken him down to catch the Greyhound bus. That was how you got back and forth. And there was a jeep that spun out on a gravel intersection, and he got thrown out and died. But after a summer or so of working the cloud chamber up there, I guess just one season as a matter of fact, we brought it back down. It was very productive, but it was too much of a logistical hassle, to get gasoline and things for the generator and so forth. So we looked around for closer places. (I'm getting to the planets.)

DeVorkin:

Sure.

Leighton:

Mainly, we decided that Mt. Wilson was enough of an elevation gain to give us a factor of three or four over sea level, here.

DeVorkin:

It's about a mile elevation?

Leighton:

Yes, about 5,500 feet. So we put two cloud chambers up there, two trailers with cloud chambers, and had them running, with a motor generator set over on one side of the old Snow Telescope building. Ira Bowen, who was the head of the Mt. Wilson-Palomar Observatories at that time, was very helpful in that. And so I was spending quite a bit of time up there, and we even had the courtesy of the monastery on occasion; if people had to work up there at odd hours, they would bum a meal from the monastery at the observatory. And I had a number of astronomy friends, and around the table, there'd be talk about this problem and that problem. The planetary stuff came up almost accidentally, in that Olin Wilson, who is now retired from Mt. Wilson Observatory, knew of my interest in astronomy and photography and things. And at that time, just after the war, the 60-inch telescope was not in much demand. It didn't have the instrumentation that the 100-inch had, the spectrographs and so forth like that, so nobody was using the 60-inch. I’d made it known that I had some ideas, to look for polarized objects and things like that—so he would call up, oh, twice a month or so, and say, "I’ve got two or three or four nights on the 60-inch, can you use it?" So based on that availability, I started getting some ideas for planetary photography, and I think I was interested in trying to get stereoscopic pictures of Jupiter, by the planet rotation. Eventually, to use infra-red film, and see if I could see into the atmosphere. It was a harebrained idea, a sort of a long shot, but I had the impression from looking at some infra-red pictures that the atmosphere was much hazier—well, less opaque. It was much more dispersed. I thought you might be able to see in. So I was going to look and see whether, with pictures taken a few hours apart—Jupiter rotates so fast—if I could get good seeing, whether in fact I could—with infra-red film, in fact see layers. It was, as I say, a long shot. I didn't know whether there would be any possibilities. But I also, just for the esthetics of it, took a lot of my pictures in Kodachrome. I did take some black and white pictures with infra-red I-N film and so on. But I took a lot of them in Kodachrome, and they were kind of interesting. I did see some things on Jupiter that struck me—and Saturn—and then Mars would come along, in opposition, and I would try some pictures of that. It was very much of a sideline. I would not call it part of my scientific work. Evenings, weekend type—that kind of thing. But an interesting thing happened to me, about 1956, when I had taken quite a number of such pictures off and on. I was still working on the cloud chamber and the pictures and that sort of thing, with the things up at Mt. Wilson. Bob Bacher, who was the chairman of the physics division here (R. F. Bacher)—he’d been on the AEC, and he’d come to Cal Tech just after World War II as chairman of physics, mathematics and astronomy—he stopped me in the hall one day. And he said, “Say, Leighton, I understand you've been going up to Mt. Wilson and taking pictures of the p1anets.” I sort of cringed down in my shell and said, "Well, yes ... that’s true, I was taking pictures up there." He said, “I want you to know, I think that's a fine thing. I like to see young people getting new ideas, to do new things. I really think that if anybody sticks in the same narrow field for more than five or ten years, he gets rather stodgy at it. Of course, you have to stick with something for a few years, or else you just are sort of a dilettante.” He said, “I think that's just fine.” I just was walking a mile high, you know. I thought, gee, maybe that's all right. And about that same time, lid been talking with Guido Münch and some other astronomers about solar problems—I’d heard about solar granulation, and about convection—the convection zone in the stars— and prompted by my planetary pictures, from which I understood some things about the earth’s atmospheric seeing, I thought I could learn something about the structure of the surface of the sun, by very similar methods—by just taking repetitive pictures, during times of good seeing on 35 mm film, rather than on plates. They always took plates, and when the seeing was good you only got one or two plates and even then maybe the focus wasn't quite right. Whereas with the film, I could bang away, and then there would be periods of a few minutes of good seeing, and some not so good. And by looking at those, I found out right away that the popular current notion of the structure of the surface of the sun was quite wrong; what my pictures showed had been suggested around 1900 by a number of visual observers. They always maintained that there was a reticulated pattern of dark lanes with bright granules, whereas on almost every Mt. Wilson picture, (everybody looked in the Mt. Wilson files for the very best pictures of the sun) the granules always looked light and dark symmetrically, rice grain structure, they always called it. I then found out that, even though the telescope was a 12-inch diameter telescope, in order to improve the average quality of the pictures, they would stop it down to four inches, when they took their pictures. So there were years and years' worth of plates up there in the vaults, the best of which only have the resolution of a four inch aperture. The first thing we did was to open up the aperture to 12 inches, and put the filter in front of the film, so that if we had to cut the light, you'd do it there. Right away, bang, out came the new things. Then it took M. Schwarzschild's Stratoscope project—Schwarzschild was one of the people, interestingly enough, who was maintaining that the turbulence was isotropic turbulence with plus and minus fluctuations being more or less symmetrical. And he even had students and post-docs evaluating this, and he was sure that if you got down to the level of an arc second or so, that you'd see very bright spots, of superheated things. Well, his own Stratoscope pictures were the things that convinced him that what we were seeing was right, that there really was a reticulated pattern. And that was kind of nice, to have had all those results there, in a very simple way. Anyway, that started me thinking about the sun.

DeVorkin:

That was before your magnetic work.

Leighton:

That was before the magnetic work.

DeVorkin:

Did you stimulate the Lockheed people actually to begin their patrol work? Because they did end up using film.

Leighton:

Possibly so. I know that there was some connection there. Well, I did not stimulate Gale Moreton, I think that's the name. He was running a little telescope about that big, with a filter on Mt. Hollywood.

DeVorkin:

Four, five inches.

Leighton:

Something like that. He would take pictures from there, for Lockheed. He was operating systematically and with good touch. He really was close to his project and his apparatus. And he got flare pictures, and other things, a lot of things which were really striking, and that was all very independent. I don't know where he got his start, but it was not from anything we did. We later sent students over and PhD's. Alan Titles who's now working for Lockheed in San Jose, is the head of its and was one of my students.

DeVorkin:

That brings up another interesting question of courses the students, and the possible combination of philosophies that you had, that might have been aided by Anderson’s ideas, and specifically then by this fellow who was the director of the division, Bacher.

Leighton:

Bob Bacher, yes.

DeVorkin:

In stimulating change and broader attitudes, as far as the problems that should be attacked—you had graduate students, in the years you were doing purely particle physics, but did they ever go along with you on some of your other ideas, in astronomy? Title, was that later on?

Leighton:

That was later, not really. I guess, when I was doing the particle physics with Carl Andersons there was a group of graduate students. A student would come into Carl's office and say he was interested in particle physics or cosmic rays or what not, and Carl would discuss it with him, and then there would be some assignments or some mutually agreeable arrangements where the student would be assigned to a post-docs or a staff member to help bird-dog something or others and it would involve operating the apparatus, and looking at film, and maybe constructing some things—you knows the things that students have to learn to do.

DeVorkin:

You were definitely working with a group.

Leighton:

It was a group. And I never felt that I had a student who came to me and said, "I want to work with you." I would have been afraid. As a matter of facts I have always been a somewhat reluctant, or I don't know what you want to say—I've not “put out my shingle,” for getting students. And almost all my students have, in the solar things come to me and say, "I want to work on something in the sun, what can I do?" And there—aside from finding fellowships for them—I was still working with Carl Anderson’s money, and ONR and everything. We had changed the title of the project to studying origins of cosmic rays, and that’s where the solar study came in. I had known that there was a solar cycle effect on cosmic rays. And so I was trying to see whether, by studying the sun, I could elucidate something about what conditions on the sun, the flares and so forth, gave rise to such a thing. So I was just pursuing one aspect of that.

DeVorkin:

In dealing with that kind of a direction, was there any element of justifying using Carl Anderson's funds, to really look for origins? Or you were taking it as an origin and you wanted to learn more about the sun in general? Because you did end up looking at the magnetic fields and that sort of thing.

Leighton:

Well, I think we always looked ahead far enough that, in getting the renewal of the operating grant, that mention was made of the things I was doing on it. It was only a small part, until the very end, when Cowan was the vestigial grantee of the ONR work in cosmic rays. But for quite some time, I'd say up through at least ‘63, ‘64, the things I was doing on the sun were a small enough part of the total cosmic ray work. that, to say we were studying the sun with a view to possibly elucidating the origin of cosmic rays and we were studying magnetic properties of the sun spots, and the circulation and so forth, was sufficient. I didn't feel and we didn't feel, that we had to be more specific about that.

DeVorkin:

So this was still ONR and AEC, all the way through?

Leighton:

Yes. I'm not sure whether NSF came into that or not. Probably not. But anyway, you were asking about students.

DeVorkin:

Yes.

Leighton:

All the solar students I had walked in the door, and said they wanted to work on solar things. I wasn't sure—I’ve always been reluctant, as I said, to accept a student. And I don't know quite why. That is, I guess I'm enough of a "Lonesome Polecat" that I know what I want to do, and I’m not ashamed of doing what I want to do. But sometimes-I'm not quite sure where it's going to lead, and I feel a little bit badly about sending a student off in some direction, if I haven't got some—not answers or anything, but if I haven't some notion that there's something for him to hang onto, let's call it a trapeze—and there's going to be some place to land. Actually, I had a couple of solar students, I think, Bob Noyes and George Simon, before I really had thesis material for them. And I was a little nervous about that, actually.

DeVorkin:

Well, in 1962, you were working on velocity fields in the solar atmosphere, and there was a joint pub1ication.[3]

Leighton:

That’s right, I think Bob Noyes came to me in 1959 or so, 1958 or ‘59, and George Simon came a year or two later. And when I started with Noyes, I was still doing the high resolution picture work. And we made a camera that would take the entire image, then.

DeVorkin:

Right. I wanted to ask you about it. That was an improvement of Babcock's design, in a way, or at least was an adaptation of Babcock's magnetograph?

Leighton:

No, this is different. I'm just talking about a camera to make a high resolution picture of the sun.

DeVorkin:

Direct?

Leighton:

Yes, a direct picture. We used 7-inch aerographic film, and developed it ourselves, and Bob Noyes helped me make the machine. And we got some good pictures. We were also looking at the magnetic things. We were looking for, not spicules, but faculae around the edge of the sun, the bright regions that are excited by presumably particles or radiation coming up from below. And what we were going to do with these, we weren't quite sure, but we had in mind that if we looked at high resolution pictures in different colors, we would get some idea of the height structure of the solar atmosphere. I don't know quite what we had in mind, but anyway, we knew it would lead to new knowledge, but we weren’t quite sure how much, and to what extent. But about that time, I got an idea for the subtractive method of bringing out velocity or magnetic fields, and tried it out again. I tried it on my own. I didn't tell a student to do it, because I just—you know, I was going to just work something up that would give me an idea of what the possibilities were. But that whole thing, then, got into a very productive stage, by virtue of proving it, with the very small aperture instrument they had. They could only take a three inch section since it had an image of two inches, which they used for spectroheliograms, calcium and H? spectroheliograms. But this big image that we got, with the 12 inch lens, was about a seven inch image, and the spectrograph wasn't big enough to cover that, and so I made an arrangement with Ira Bowen at Mt. Wilson to actually modify the spectrograph, so as to make it possible to take full disc, large image spectroheliograms. And at the same time, we built into it some features that weld made for the smaller version that was there, which made it into a really powerful instrument. And we then exploited that for the velocity fields and the magnetic fields, for quite some time—about five years or so, we worked on those things.

DeVorkin:

Did you talk about your design ideas with Babcock? Because you were definitely building on some of his techniques. You mentioned very strongly, in your 1959 paper, "Observations of Solar Magnetic Fields in Plague Regions,"[4] that a great step forward and this is sort of paraphrasing, was Horace Babcock's invention of the solar magnetograph, 1953, where he used photoelectric measuring of Zeeman splitting. But your technique allowed for larger areas. He could only observe very, very small areas.

Leighton:

Yes, he would have to scan the sun. It took a long time. It was a scanning thing. At the time, it would only give out a graphical plot of the solar disc.

DeVorkin:

Time resolution was very poor.

Leighton:

Time resolution was poor. The spatial resolution was not very good, but the field resolution was excellent, and of course, he discovered many very important things with it. But what I was after was finer spatial resolution, and I thought that by going to the limit of the photographic plate, possible small structures in the field could be seen. And that, I think, paid off at the time.

DeVorkin:

It did. You found two components, two granulations. And I'm just wondering, were you suspicious that they existed?

Leighton:

No. This was not like the decay spectrum of the mu-mesons, it was a new, unexpected thing—but it wasn't quite that we simply stumbled onto it, because we were measuring something we knew what it was that we were measuring at the time. But it was a nice result, and we sort of said, "Aha." You know, you have those times where you say, "AHA!" in neon letters. But this other thing you're referring to—the supergranulation-somewhat far along on the project. I was studying magnetic fields, but I wondered, what would the velocity field look like? I thought I knew. I thought I knew what the velocity field would look like, and that I'd see upward moving things and downward moving things, and I thought I would see bright things moving up, and cool things moving down, and I would look for correlations. But I asked myself: wouldn't it be interesting to look at the acceleration, look at the time change of velocities? And that was where that started. [pause]

Leighton:

We were talking about the two patterns in the sun,[5] which was kind of fun, saying that's where you get the "Aha!” feeling. And I decide I would use the apparatus we had in what I call the Doppler mode, by taking pictures on one side and then the other side of the spectral line, so when the line shifts from the Doppler effect, it makes it brighter or darker, in the subtraction technique. And I got pictures, which were not terribly informative, at first. But I took a number of them, and I saw peculiar patterns, especially when I used the small image, so I got the complete sun, with the rotation effect and everything all on it. And it had these funny lumps around the edge. And it took me a while to realize that that represented big flow patterns, the thing we now call the super-granulation. And then, the other thing was, measuring the time change of the velocity field. You understand, you have to scan the image past the slit, or the slit past the image—over a period of time—so a minute or two elapses, during the time you're making an image.

DeVorkin:

So your technique was not instantaneous, either. But it was quicker.

Leighton:

Well, each line along the sun is instantaneous, yes, but it takes a minute or two, to traverse, or a few minutes to traverse over whatever part you're looking at. Well, I got the idea of immediately traversing the other way, and then, differencing. Each one is a difference, namely, it's a brightness, differenced to get the velocity signal. And then I take the time difference of these two. And since I’m going one way on the one line, the other way on the other, the time difference is zero at one edge, and it builds up to a maximum delta t at the other. Then I found a strange thing. The pattern was washing out, after a particular period—the periodicity of the thing. That I think I saw first. And then afterwards I saw the other thing we call super-granulation.

DeVorkin:

Do you recall how you were able to interpret that, as a global event? The super-granulation?

Leighton:

The super-granulation. Well, I saw it all around the edge of the sun. And I recognized that it was a horizontal motion on the sun. And I saw it at the poles and equator and everywhere.

DeVorkin:

So it was really direct observation.

Leighton:

Oh yes. Yes. Anybody who saw that picture, and had the method explained to them, so they knew what they were looking at, would say, “Aha.” The interesting thing was that “brighter than average” means it's moving toward you, and “darker than average” means it's moving away.

DeVorkin:

—you set up the filter—

Leighton:

Yes. All the lumps were bright on the near side, and dark on the far side, see. And so, it took just a couple of minutes to realize that that was flow toward me on the near side and away on the far side, which meant that, the only way that can be is that it's something coming up from the center of sun.

DeVorkin:

You were mentioning, a student asked you, how come it wasn't the other way?

Leighton:

Yes, how come it didn't come in from the outside? And that took me a while to show him, from density arguments and things, that you couldn't really do it that way. Well, anyway, there were centers of supply, and then horizontal motions on the sun, and that, coupled with the network that was well known the calcium network and the H alpha network, immediately suggested the connection between this big scale motion and the moving of magnetic field lines to the boundaries. And that then also made clear some things we saw on our magnetic pictures, of the bright calcium emission going with magnetic fields, and that made the network and everything—so all of a sudden, the physical picture came through. It was a very nice feeling, as I say, to have that "Aha" feeling, or “Now I understand.”

DeVorkin:

This stimulated you to go on and to produce a comprehensive model for the solar atmosphere.

Leighton:

Well, for the solar cycle. Yes. I got interested in those matters then. I think the solar oscillations were the most unexpected things that we found-the five minute oscillations. And then, I guess, that just came through, as I say, with this time difference. This is not the super-granulation. This is the ordinary granulation that you see in the center of the disc, which exhibit up and down motions, mostly.

DeVorkin:

Right.

Leighton:

We'd been looking at the acceleration, namely, the change in the velocity pattern, and when we looked at the difference over time, we found that the difference pattern reversed itself after a certain time, and then came back again, so we got the effect of the oscillation. But there was some confusion about it. And what I can say from what I recollect, is that, after looking at a number of these so-called Acceleration pictures, I suddenly, almost like turning on the light in the dark room, you know? I all of a sudden realized that it was an oscillation, that would do what I was seeing. Since I was measuring an acceleration, I took the velocity field from time t1 to t2 and the minus field, the negative of the velocity field, from zero to plus t2, or whatever it was. And superimposed those, so at zero time, there was no signal—namely, within a short period, the velocity field didn’t change. Therefore, when I matched it with its negative, it canceled out. But then I noticed that, sure enough, the velocities changed with time, and the big signal developed. And what mystified me was that it went away again. And then, I got the idea of doing it very slowly, so I’d be able to see it over a longer time, and then there were bands—two cycles or something like that. But I remember distinctly the feeling, the sudden knowledge that it’s an oscillation, and I can predict what I’m going to get tomorrow, because I can measure the period. Before it was just blind, you know, “Lets see what happens if we go slow—if we go fast—“ I actually predicted: “OK, today’s picture, we’re going to get a null at this particular place.” And sure enough, that’s right where it was. And all up to that point, it was happening so fast; I’d developed a lot of the plates, for the cancellation, in my own dark room at home, not at the observatory. A lot of it sort of developed with just me, and Bob Noyes was in the meantime working on his high resolution camera, building that up, and I was working on the velocity field by myself. So suddenly, when I really saw what we had, I though: gee, that’s very nice, now we’ve got to study this. And so at breakfast one morning I told Bob Noyes, I said, “I know suddenly what the subject of your thesis is.” I told him. I said, “The sun oscillates with a period of five minutes.” He said, “I don’t believe it.” So we then went on, and got a lot of plates, and measured the thing, and used different lines, and tried to measure the height structure, to look at different levels through the atmosphere, and everything like that. Then that was announced at a meeting in Verona (Italy). I’ve always been very bad at publishing, and so I didn’t immediately send off a note to anybody or anything, but I did talk to people. And at the meeting at Verona, in Italy, I discussed it. That was sort of the official public announcement. Then, I've often thought that it was from that meeting that word got back to Sacramento Peak, because almost immediately thereafter they said, “Oh, the sun oscillates with a period of five minutes—“ And I never was quite satisfied that there hadn't been some prompting. But then, you know, it's one of those things. Nothing much hinges on it, and it doesn’t really [matter]. But the super-granulation, I think, was strictly our own thing. And it showed up. I think even the name came from here.

DeVorkin:

I’d never heard the term used before that time.

Leighton:

Well, weld been studying the solar granulation, the convective granulation. And of course, for a long time, for fifty years, the chromospheric network had been known, from the Kline spectroheliograms, from the early Hale days.

DeVorkin:

Sure.

Leighton:

And it was even possible, and I don't know the literature well enough, that somebody suggested that it was a convective pattern. But it had not been shown, you couldn't see it directly by spectrograms. You could see wiggly things. And then Michigan even had things that had a funny tilt to the lines. And then later on they said, “Oh yes, that's what that means, that tilt means it's moving toward us, and this side away from us—“

DeVorkin:

You're talking about granulation?

Leighton:

No, I’m talking about super-granulation now. I’m talking now about the big pattern, that showed up. But it was when we found the big scale of it all, and then, by more or less detailed observation, showed that it matched the pattern. Simon’s thesis work was to show in detail that they really coincided geometrically. That the thing was established as being physically—I can't call it convective, but at least, a mass motion of systematic cellular motion. And since the granulation was the motion, going with the convectively unstable layer, we wanted to indicate that it was a relatively low velocity, velocity field, of a cellular nature, and so we just coined the term “super-granulation.” And it sort of stuck. You could have said, the chromospheric network, but the trouble is, that that had a specific meaning, namely, the appearance of this reticulated pattern, and it did not convey the clear notion that there was a convective circulation, or circulatory motion.

DeVorkin:

Were you asking, historically, I mean, just as an aside, whether that network was interpreted as a convective phenomenon at the turn of the century?

Leighton:

Yes. I’m not sure whether it was or not.

DeVorkin:

It was.

Leighton:

Was it? I see.

DeVorkin:

Very much so. But they thought it was a region of condensation. Didn't have a very good model of it.

Leighton:

I remember, taking some of those high resolution direct pictures around to Colorado, or showing them to Leo Goldberg whenever he'd pass through, and so forth. It raised quite a bit of interest. They had the wiggly lines, remember, the vacuum spectrograph at McMath-Hulbert Observatory was the real breakthrough in fine resolution, and they had wiggly lines, and were talking about trying to get at the micro-turbulence component of the curves of growth, and so forth.

DeVorkin:

Yes.

Leighton:

I don't think it was ever satisfactorily shown. I don't think the so-called micro-turbulence ever really has been found. I don't know enough about this thing right now because I haven't followed it, but at that time of course also R. N. Thomas was doing the non-LTE things, and M. Schwarzschild was predicting very hot, very fine things, below the limit of resolution, I think partly to try to have a basis for the rather high microturbulent component necessary in the curve of growth. But I don't know the details. Anyway, it's true that then once we and others started really looking at these things, and got a different, a new physical arrangement, for the hierarchy of sizes and systematics of the motion and so forth, I think it then stimulated a lot more studies, and there are some beautiful things going on now, with Roger Ulrich over at UCLA, doing Fourier Transform studies of the solar photosphere, and getting the various modes of the atmosphere. This five minute oscillation, he gets into the K plane, and gets the families of curves. He's shown me some of the things, and it's amazing, you know, what sensitivity and statistical significance he can drum up from that, at Sac Peak[6] now.

DeVorkin:

Your solar physics phase lasted—

Leighton:

—my incarnation?

DeVorkin:

—incarnation, lasted pretty much until the space probes, the planetary space probes.

Leighton:

That's right.

DeVorkin:

But before we get completely into that, there are a number of interesting dates. You soon entered actively into solar physics, pretty much with Sputnik. I’m wondering if there was an effect, not due to Sputnik itself, but to the coming of the Space Age, that brought you to planetary astronomy, to solar physics? Was there an element possibly of financial support? Were there pressures to work in those fields?

Leighton:

No, not anything involving the sun. The sun was entirely an offshoot of the cosmic ray thing, which then took on momentum of its own, because as soon as we had found what amounted to new phenomena, and had a way of measuring them. That became a worthwhile thing, you might say, whether or not it led to any new explanations of cosmic rays. You mentioned the solar cycle, though, also. I did get interested in the Babcock model of the cycle, with the flux ropes and so forth. As a matter of fact, I remember having some conversations with Horace, not at the monastery, but the little snack house, what do they call it? The little galley, between the 100 inch and the 60 inch telescopes. When I would be using the 60 inch, I’d go over at midnight, and have my midnight lunch, and then whoever was astronomer on the 100 inch, we'd be together there and talk a bit. Once in a while it would be Horace Babcock. And he must have been developing his model of the solar cycle, because at the time he came out with that idea, of getting the Hale polarity rule, by this stretching of the lines of force, by the flux ropes, and the differential rotation, I had the feeling, not exactly of "Aha!" but of”of course.” You know, sort of "God, why didn't I see that?" You know? But that was really a nice step, that Horace made on that. Of course, he looked at the magnetic regions also. But at about that time; I went to a conference in Europe, and I'd had the experience more than once of agreeing to give a paper, a talk on some subject or other, and then not thinking about it, and then of course, at the last minute, it's always inconvenient, because you've got other things to do. Then, I hadn't started on anything really to say, but I had some general ideas of what to talk about. In this particular case, I was supposed to talk about the magnetic structure of the sun.

DeVorkin:

What year was this, again?

Leighton:

It would have been in the sixties. When was the Verona Conference? That must have been '63 or so. It was at some Bavarian lake. An IAU Conference. It had to do with solar magnetism, solar and stellar magnetism, I think that was it.

DeVorkin:

That certainly can be located.

Leighton:

Yes, I’m sure it can be. Well, anyway, I had to give a paper there, about the solar magnetic field, and in connection with that, I was putting together what I was going to say. It was not a big deal paper, so I didn’t write anything out or anything. But I was thinking about it, a night or two before, and all of a sudden it struck me, this business that Babcock was seeing, and this super-granulation, that there was a random walking of the magnetic field. I’m not sure that that idea holds up to quantitative rigorous analysis today. But the notion of the spreading effect of independent sources and so on, by superposition in the usual sense of random walk diffusion. It suddenly struck me, and I said it right there, having just a sort of a feeling it was sufficiently close to something significant that it would be worthwhile to mention. Then, the moment I got back, I made a random walk on a sphere, and checked it against a number of things about the way the prominences go with time, in latitude versus time, toward the poles through the solar cycle, and found the diffusion coefficient, how many square kilometers per second it took to explain the migration of the magnetic fields. It was at least comparable with what you got from the super-granulation, as well as we knew the lifetimes and the cell-sizes of the super-granulation then. So, that then led to the next notion, which was that: well, maybe the solar cycle is an oscillator, which essentially was driven by the differential rotation stretching the lines of force; and I recognized that the tilting of the sunspot groups provided dipole moment changes of the opposite sign to what was already there. And that the diffusion of that, (I hypothesized diffusion of it) would leave inside the sun a meridianal field of opposite sign, which would then become amplified. And so, I hooked that up into this quasi-numerical model of the thing. I felt very good about that. Now, I think people would call that a rather rudimentary thing, but I satisfied myself that at least certain aspects, including some randomness effects, were sufficient to describe the solar cycle. And then, I went on to other things, and didn't pursue it. I had one more step I wanted to take, to put in a depth coordinate, and try to separate out the radial and the lateral variations of things, and maybe even put in some global circulation. I was still going to do it on a very empirical basis, but then, there were a lot of people, the Japanese and people at Boulder and elsewhere, who were working on, you might say, fluid dynamic models and things. And I decided not to pursue that very much farther.

DeVorkin:

Because other people were working?

Leighton:

Not so much. Well, it does bring in another thing, as long as we're talking about me. I can maybe tell you a little bit about how I work, in a sense.

DeVorkin:

Yes. Exactly.

Leighton:

And that is, I have always shied away from things where I felt that, if I did something or didn't do something, that next week it would be done by somebody else anyway. The corollary to that is, that if you have to feel, “If we don't measure that today, Jones and Brown are going to measure it tomorrow, and then they'll beat us out” —I don't like to be in that kind of an endeavor, because, it isn't so much I don't like competition, so much as it is, I think, a waste. Unless, of course, you don't get the same results, and then you can argue about something. But that's something else. I mean, if you always are pushing because “these guys are going to get ahead of us,” or something like that, I think you're in the wrong field. Or at least, I feel I'm in the wrong field. So I’ve always tried to do things where I could have the feeling that if I didn't do it, it wouldn't be done for quite a while. It's kind of nice to work that way. I guess I'm just too much of an individualist or something, for some of the group things. And yet, some of the things I’ve done have been very much team efforts. So, I don't know—but I do consciously try to avoid situations where you're competing against some specific other people, working with essentially the same resources or with the same ideas and so on, like that.

DeVorkin:

But the three things that I would immediately identify, first, your particle physics work; then your solar work, but really the Mariner work, even though you were developing the instrumentation as much as anyone else; and then, the fact that you're associated in radio astronomy now. All three of those areas have just this tremendous1y localized, centralized aspect, where everybody has to deal with the same instrumentation, and there is, or seems to be at least in radio astronomy, the feeling that, if you don't make the observation now, somebody else will.

Leighton:

The radio astronomy is getting to be more like that. It's true. There are a lot of interferometers being built and so forth. And yet, to put it another way—maybe, leave the business of competition out, because that isn't per se, the thing I'm thinking of. I have more the feeling that I'd like to make my own contribution. I don't want to just make something which, if I didn't do it, would be done next week anyway. I’d sort of like to do something which is, in some sense, unique. I don't know, it gives a person a little more feeling of having participated.

DeVorkin:

Well, in a way, could that be why you've always been very close to the instrumentation itself, because you were building the instruments that did not exist before, and otherwise you couldn't have made the measurements.

Leighton:

That's one way to do it. Yes. And I guess the theoreticians like to think of new things that haven't been thought of before. That's the same feeling, I think. So, I don't know, anyway that's been a strong motivating factor, in my own thing. And I don't particularly respond well to deadlines and rush-rush things—although I like to do things fast. Once I do things, you know, I like to get at them and work and get them finished. And I think I do things reasonably rapidly. But I don't work well if somebody says, "OK, next Tuesday we've got to have that ready for such and such." I just don't respond.

DeVorkin:

Right. Especially when you're working, again, to take the present example, with these ten meter dishes that have to have surfaces accurate to just a few microns.

Leighton:

I'm aiming at below 10 microns, rms. By machine shop techniques. It's ridiculous in the face of it, and yet—you know, by just paying careful attention to things, it turns out that you can get a handle on them.

DeVorkin:

Eventually I’d like to ask you about your techniques. I know that it really seems to be a revolutionary thing: you're getting down to optical accuracies.

Leighton:

Well, quasi, optical. We still have a factor of 50 to go.

DeVorkin:

Well, going back then—I had asked you about the possible effect of Sputnik, and we came out with a general answer that it really wasn't Sputnik itself, or any Sputnik-oriented interests, and yet, there is a very important application of understanding the sun to space research.

Leighton:

That's right.

DeVorkin:

In developing the research along the lines of your interest, and certainly I can see how cosmic rays fit in very nice, beautifully, in fact—wasn't there also possibly the feeling that you knew that money I was going to be available? I know that you can't give a direct answer I to that either, because, you continued on ONR-AEC support, but eventually you became linked up with NASA, with the Mariner people.

Leighton:

Well—it's "the cart and the horse" sort of thing. Let's just try, maybe I can give you a reasonable picture, and maybe you can help I draw the conclusions.

DeVorkin:

Sure.

Leighton:

If I just say that, in the cosmic ray era, or “incarnation,” money was not exactly "no object," but it was not a limiting factor. it was ideas, it was doing something with apparatus that we had, and getting new ideas of how to use it, and the money was there. Now, we didn't ever ask the question: is the money available to do that? Well, until we made the addition on the building, to put in the big magnet and things, and that was a big deal thing-cost $20,000!

DeVorkin:

Is that all?

Leighton:

Right. But when Carl Anderson got that, we knew we were proposing something, for us, unusually big at the time. Nothing compared to an accelerator, but it was only one little group, you see. So, as I said, money was not the problem there. In the planetary project the telescope was available. I almost got the idea to fit the opportunity. It was just that live always been interested in astronomy, even from an amateur point of view, and as I said, I don't want to ever lose my amateur standing. So it sort of fitted in; it was something I wanted to do and liked to do, and I had some ideas of how to take better pictures of the planets. And so I did it. And the money was shoestring. It was no problem. A hundred bucks or something like that, and I could always get. With the sun, I did the initial things with the existing apparatus, and my own time. You know what I mean, non-scientific time, home darkroom and that sort of thing. And when I got some results that looked as if the method could be refined, then I got Bowen to allot some money. Or he offered to spend $5,000 on the spectroheliograph. And I was able to, all this while, use money from Carl Anderson’s thing. But I wasn't consciously in any situation where I had to say, "I’d like to do that. I wonder if I could get support for it?"

DeVorkin:

Well, not quite in that direction, but in the direction possibly of saying, "Some day we're sending men out into space."

Leighton:

No, nothing.

DeVorkin:

—“and people are going to be worried about what the sun's doing—”?

Leighton:

No, no, I was always much shorter range than that. As a matter of fact, I was looking backwards rather than forward: Namely, what really accounts for all the observations? I was reading a lot of books about the sun and everything. Kuiper's volume[7]—a great big thing. I read that three or four times, if I read it once. And Kiepenheur's article in there on solar activity was very influential. It made me think. I kept trying to make physical pictures, for myself, of what the sun—

DeVorkin:

Had you read further back? Possibly, the Maunder minimum?

Leighton:

I stumbled across it. I had Agnes Clerke's book on THE HISTORY OF ASTRONOMY in the 19th century. And the SOURCE BOOKS OF PHYSICS. The source books in physics and astronomy, by Magie and Shapley, respectively. I read both of those, and they're both very good things. So all that while, there's no question about my interests. Then came the infra-red work.

DeVorkin:

You'd done some work on cool stars with Gerry Neugebauer.[8]

Leighton:

We'd built our own telescope, and it was that telescope that led to this 10-meter telescope, here, ultimately. Well, I like to build telescopes. And so we figured out how to make a better infra-red telescope, very quickly and cheaply, to do a survey of the sky.

DeVorkin:

You made a fiberglass dish, didn't you?

Leighton:

It was a spincast epoxy, using the parabolic shape of a rotating liquid. Other people had been doing it too. Kuiper had one, over at Arizona, made I think by the Kennedy electronic people. I think they became ESCO, who now make millimeter-wave dishes on the East Coast. Anyway, we pursued that, and that was with NASA support. Around in the early sixties came rather massive amounts of NASA money, here on the campus. And for reasons that I'm not quite clear about, but possibly having something to do with the fact that I had worked on the sun and was working on the planets and the sun some; and then shortly, in '61 or '62, I was dragooned by Bruce Murray and Gerry Neugebauer into participating in the Mariner-IV photographic experiment, television experiment, and the reason for that was, as I recall, that there had been no reasonable proposals for a photographic component of the mission, you know what I mean, on television, for pictorial work. I think people had made studies even, Harvard and other peop1e had made studies for NASA of camera systems and stuff like that, some written stuff was available. But nobody had proposed, for that mission putting together a particular kind of a TV camera.

Leighton:

But the trouble is, you see, you couldn't build a telescope and say, “Here is my telescope, I want to fly it on Mariner.” The whole thing was an integrated spacecraft, and JPL had the problem of putting together a set of experiments that would make some scientific sense, out of the proposed things that there were, that could be integrated aboard a single space-craft. I guess it was just the fact that I was at Cal Tech and Murray and Sharp and Leighton, and maybe there were one or two others, Leovy and so forth, did the Mariner-IV project. I think my stabilized image photography at the 60-inch was directly the reason why Murray felt that he wanted to be sure I was on the team. Now, I didn't have much to do with the actual thing, except I knew something about photographing Mars. I knew, there were some things which—if we wanted to go into that detail—?

DeVorkin:

Yes. To some extent.

Leighton:

—were key things in the success of the later missions. One was that in the Mariner-IV, the encoding scheme was such that there were just six bits—what's that, that's 64 levels, right? Gray levels, 64 data numbers, that are distinguishable. The pictures came back VERY low contrast, and people to this day think it might have been scattered light in the optics and so forth which smudged it down. But every picture of Mars since then has been very low contrast, but people just wouldn't believe for a while that that was the case. And so when we got to Mariner VI and VII, the next follow on thing, we told them we would need at least eight bits of encoding. And that was what saved that mission, because there was a dust storm, you remember. It was all very low contrast. (I guess Mariner IX was the one with the big dust storm. When they first approached, it was dusty all over the place.) And it was only being able to dig out the signals. We had to keep the noise levels low, you know, the harmonic distortion, harmonic frequencies low, so that you can really use the bits down there, but if you don't have them to start with, there's nothing you can do. And we were limited, in the Mariner-IV, by contrast, by very little contrast.

DeVorkin:

The contrast enhancement techniques, the computerized techniques that were used. Did you have someone on your team who was already capable of this?

Leighton:

JPL has really done a lot of pioneering work in that. I guess they were developing it. They learned from Mariner IV and they were developing the image handling procedures. We did a certain amount of it which might have helped them in deciding on some things to do, in terms of contrast. The sharpening is all theirs, but the contrast enhancing and so on, I think we made some contributions on. This is all very much of a team thing.

DeVorkin:

Were you in the room at JPL? When the first pictures started coming through on Mariner IV?

Leighton:

Yes. As I remember—yes, indeed I was. Yes, I remember that very well.

DeVorkin:

Who was the first person to see a crater and scream, “There's a crater!”

Leighton:

It wasn't anything like that. As a matter of fact, it was one of those things, again, where you kick yourself afterwards for not realizing it. When somebody said, "What do you expect to see?" We would have said, “Craters.” It’s obvious. You know, there'd be craters and everything. And yet, the fact that craters were there, and were a predominant land form, was somehow surprising. And the pictures were of such—I can’t say, poor quality, but at least, the limitations were so severe, in terms of the six bits and the very small coverage and everything like that, that we waited a week or more, after we knew there were craters, before any kind of official announcement was made. And I’ve forgotten the details at the time. You'll have to find out from the newspapers or something, I've just forgotten. But they were all off-bound limits and off-limits. At JPL things were protected very much, because it's one of those things where, if somebody had leaked "craters," then—you known—I think what we were trying to avoid was being drawn into a detailed discussion of things before we had had a chance to make any kind of measurements of the things. So we took out a week or two, and made measurements, and then had a press conference. It was not a very happy time, in the sense of the high pressure. Well, it was good to be there, for the results and everything, but the high pressure, and really the limited amount of information that came back, was an awful lot of effort, for what I thought was not very much scientific gain.

DeVorkin:

There’s a certain amount of popular gain, though. Certainly, your time lapse motion pictures were distributed very widely. I remember seeing them in many different places.

Leighton:

Yes. I just got a request today. From JPL. I told them that I really don’t want to drag it out again.

DeVorkin:

Well, we get them—as teachers—from the Indiana Film Bureau, Indiana University. All over the States, you can find it available in many different film libraries. And in the same way, I mean, beyond, certainly, scientific values, in the sense of being able to look at the Martian surface, the tremendously important contact with public imagination.

Leighton:

Oh yes, absolutely. And that's one of the best parts of it all. Some of the letters that came in, from the milkmen, the dairy farmers in Oregon—they'd been watching TV at, I don't know, 5 AM or whenever the thing went over, you know—they said, "I'm not very close to your world, but I really appreciate it, keep it going." I thought that was kind of nice.

DeVorkin:

How do you feel about support for such types of projects? Obviously, you love to be in the center of these really incredible projects.

Leighton:

Well, I have to admit, I have some—not misgivings or guilt, it isn't misgivings or anything, but it is that, I've always felt that the space program—you can't call it “wasteful,” but it is at least poorly structured from the point of view of returning scientific information per dollar spent. Say you wanted to devote a certain amount of money, over a period of time, including mainly space experiments, say, for science. And we're not saying that you're going to develop the boosters and all that sort of thing. There's other rationale for making boosters and shuttles and stuff like that. But as a scientific component of the space program, you want to bring back the most science within the area of coverage that you can for the amount of money. I have always felt that NASA spends its money very poorly, in that regard. Possibly they felt constrained by Congressional or executive or other guidelines, against expending money for essentially ground-based activities—either observations, or construction of equipment, or what not, or even data analysis. It's always been: if it will help us with that mission, if it's an approved mission, we can spend money for it. If it’s anything else—sorry. You know. I think time and again, the atmospheric pressure on Mars, the water vapor on Mars, the temperature of Venus—and there's other things—the rings of Uranus and so on, have come first, or at least equally from ground-based work, and the space work, while very good and even more accurate and a unique contribution, in these particular things, the prior knowledge of those properties, if we'd known them a few years earlier, could have greatly enhanced the scientific return from the missions that were flown. And so I’ve always felt, you know, that one of the first things NASA should have done was to build four more 200-inch telescopes.

DeVorkin:

To give them a better idea what they were looking for?

Leighton:

Yes. And let astronomers use them and everything. Even if they want to say, "Spend 30 percent of your time on planets for the next five years, because we've got to study planets first," or something like that—that would have still been a good investment. As it was, one mission—one damned spacecraft mission would cost as much as five 200-inch telescopes, plus the mountains to go with them. You know. And I felt, it’s so out of balance. I’ve said it before. But always the office of science applications felt that it has to be so big—that1s their concept, it has to be so big. So undoubtedly, it's a hard problem. But live always felt it was just the wrong solution, because it's not at all the optimum.

DeVorkin:

Well, a situation like Spinrad and Münch in ‘62, determining water vapor and oxygen content on Mars. They were well within the bounds of what was found by Mariner, by the landers and I guess by Mariners to a certain extent. Yet it didn’t seem as if the Mariner detectors were designed really to look for that range of water vapor. Was there a mistrust in any kind of ground-based information, by the teams that were building these instruments?

Leighton:

I don't know enough about those things to tell. And there are others who would know more about it than I do. I can tell you things about the photographic component. That part.

DeVorkin:

Yes, it's different. I recognize that. Well, there is this question, that ground-based research has been around for a long time, and especially with Mars there's been a lot of controversy as to the extent of the atmosphere there.

Leighton:

Yes, right.

DeVorkin:

And do you think there was a certain degree of skepticism by mostly teams that do primarily space research, as to the ability of any ground-based operations, just from the legacy of conflicting testimony?

Leighton:

—I’d put it the other way around. I think that many of the aspects of the Mars missions, at least, including Viking, were so predicated upon what were taken to be valid ground-based observations like the wave of darkening,[9] remember that?

DeVorkin:

Yes, I remember that.

Leighton:

All the ideas of where you would look for life, what would be the general surroundings and things, were so much predicated on that, that I thought it was ludicrous. You notice, there's nothing more about “wave of darkening.” It’s quite a different place. The reality of it just suddenly waked everybody up. Percival Lowell left us with all that business, “waves of darkening” and things. And unfortunately, I shouldn't mention names and I won't, but some of the members of the scientific team are basically romanticists. You know, they are just unbridled romantics: “And if you can't prove that there isn't life on Mars—well, then there must be life on Mars, and let's go find it.” Well, it changes. It's got dust storms and polar caps and things. So, it's a possibility anybody would recognize. (crosstalk)

DeVorkin:

There is, of course, some feeling presently that one can get money from NASA or NSF if you do design a package that has some certain percentage chance success, in detecting life in the universe somewhere. And it seems to be that, even in the earliest Mars probes, in your writings, you specifically came out and tried to say, “Well, our probe wasn't designed to look for life or prove life did not exist on Mars.” Was this an actively sensitive area?

Leighton:

Only from the point of view of the overblown importance attached to it, in the popular press. And you knew you were going to get asked the question, and if you didn't mention it, then it either was left out because you knew something you weren't saying, or else—you know, it was just a way of recognizing that we didn't design it. It was not designed to look for life, nor were any signs of life found, but-you know, that's it.

DeVorkin:

How sensitive, let's say, were the government support agencies to popular press, on these kinds of questions? How far out would they want their project scientists to go?

Leighton:

Well, I guess I never was involved with the Viking thing enough.

DeVorkin:

Well, Mariner.

Leighton:

But in Mariner, there were some preparations for the fly-bys, in terms of PIO, public information operations. And they took the form of trying, with the people who were experts in the public information business, who deal with the reporters and things, trying to put the scientists in the right frame of mind to receive some of the questions they knew would be asked. It wasn't that we were prompted or told what to say, by any means. It was only that, you know you're going to be asked such and such and so and so, and so it would be just as well if you'd thought about it beforehand. When the results were partly in, and we knew what they were and the public information people knew what they were, we could see more specifically what kind of questions would arise, and so, there'd be a session the day before, or something like that—and then, of course, the releases are made up by that time, so that when the press conference happened, there's a specific release which says what happened.

DeVorkin:

Did you usually see these releases before publication?

Leighton:

Oh yes. Yes. They'd been edited and changed according to the scientist's needs. See, they were written up mainly by press people —the public information people—but very well done—and with the NASA headquarters people, also, on that. Now, you were trying to get something about seeing, before, what the sources of support would be—or seeing, since we’d need information in the future about such and such, we ought to work on it now, or something.

DeVorkin:

In terms of the sun.

Leighton:

In terms of the sun. Oh, I see. You weren't thinking of that for the others.

DeVorkin:

Not so much for the others.

Leighton:

All right. No, I did not look at that, in that way.

DeVorkin:

Yes. In the case of Mariner, I see how you came into it, but I don't understand why there weren’t other people working on the television packages. That's a surprise.

Leighton:

Well, but the trouble is, it got very expensive. And the techniques, they pushed the techniques at the point, at the time very far, and so I think that no ordinary investigator, no person in a lab somewhere, even if he had the technical know-how and desire, even, was in a position to say: "Well, I will now buy television components and put together a prototype television set." Even if you made a proposal to NASA, they would say, "What mission is it for?" And then there would be a request for proposals and so forth. So I think the right avenues had been used. But it was that none of those people had had experience with the possibilities or the needs of the mission, to make a sensible proposal. And it takes a lot of experience, a lot of insight, to do that. We didn't make a proposal, either. We were sort of approached by JPL. The people there had done a lot of thinking about it, but they didn't have any scientists. They had the technical know-how, and had the tubes and everything else, and they'd even sent the Rangers. Remember, there was a bad series of Rangers, but they had good cameras. And they had a lot of experience with television cameras and so forth, and to the extent that they thought they were just going to the moon again, they were well up the curve. And so by the time they latched onto a few of the scientists, and we got together and made a group that would do it, it just was a leaderless, headless thing, where there was knowledge and everything, but it was not in places where the people would propose as a team, or could propose as a team. So it was a sort of a fluke, in a way.

DeVorkin:

I see. Is this one reason why you said that, what you really retrieved scientifically out of the mission, out of that phase of the mission, was less than you would have hoped for, considering the expense and the amount of time?

Leighton:

Oh yes. Yes. You asked me, how I felt about the kind of money and everything, and I feel somewhat guilty about 140 million dollars, to bring back 20 or 18 pictures, whatever it was, from Mars. And yet, in later respect, it's a necessary step. The first triode cost-you know. The one really nice thing that came out of the Mariner-IV was, it got Murray and me thinking about the atmosphere, and the low pressure and so forth, and the fact that there's carbon dioxide and everything. We had a lot of fun, quite on the side. It had nothing to do with the Mariner mission per se, but we then worked up our little thing on carbon dioxide, and he'd had some experience in thinking about that on the moon, and I still think that he and that other fellow whose name I've forgotten, predicted, and I think it must be true, that in some of the permanently shadowed areas near the poles of the moon, there might well be deposits of ammonia and methane and things like that, where the sun never gets, and there's not enough internal heat coming out. The stuff just radiates into space, and gets cold and cold, and if anything's liberated near the equator or strikes, it random walks, hops around in a kind of atmospheric [dance], until it gets trapped in the cold trap. And so there's a bunch of cold traps up there, full of molecules. And that notion, combined with some other things about Mars, made us realize this. Of course, now, it turns out there is water ice in great quantities, on Mars, but the polar caps, the transient polar caps are carbon dioxide, as we know today. That was kind of fun. That's what I got out of Mariner-IV. Ideas for that. The Mars atmosphere.

DeVorkin:

That's interesting. You continued, of course, with planetary work, to a certain degree, but you're really not in that field any more. How did you make yet another transition?

Leighton:

Well, I got "transished" into the chairman's office, here, for five years.

DeVorkin:

That was starting in '70.

Leighton:

‘70, yes. And Mariners 6 and 7 (1969) had just finished, and there were still some analyses going on in the pictures, which never really got finished. It turned out, Mariner 9 overtook it, and made a better hit. But the new job mostly took me out of research, except for my preliminary work on the 10-meter dish.

DeVorkin:

Was this dish an outgrowth of your early infra-red studies that you mentioned?

Leighton:

Pretty much. Neugebauer and I had made a couple or three of those spincast mirrors, just as replacements, one for another, on the telescope, and we used the telescope for the IR sky survey. He continued in the infra-red area and is very big in that right now, and has been all along. But we built twice as large a dish, starting in about '69, '68 or so, and that turned out to be not very good. It still exists, but it was not the way to go. We did it with spincasting like the others. But we clearly foresaw the need for larger dishes. Then, about in 1971 or so, we discovered something in the manufacture of a twice as large dish—namely, the way we built up the support frame: out of tubes.

DeVorkin:

Underneath the dish?

Leighton:

Underneath the dish. And we had a very simple design, at the time, which, although it did have certain mechanical design defects which are not present in our present dishes, made it very easy to manufacture: namely, because of the high degree of symmetry there were only a few different lengths of struts, and they were very easily made on a milling machine to a very high accuracy. There was no need for fitting and welding, no templates or framing jigs. You just followed the computer print-out, and put in members wherever they had to be. We used jig-drilled holes for all the posts where the struts attached. One could bolt it together in one morning, and there was your support frame, without any more trouble. It was really very nice. And that's how we now build these bigger ones. We count out our 800-odd pieces of steel tubing, and there's a certain parts-fabrication effort, but there's almost no effort at all involved in the actual erection of the thing into the right shape. You don't have to cut it and weld it and stress-relieve it, and all that. We just assemble it with pins. My wife says I’m playing with my Tinker Toys allover again!

DeVorkin:

That's interesting. Let me see if I understand you correctly. You had found a design for—

Leighton:

—a fast method of building up an accurate tubular support structure, in a parabolicoidal shape. One thing we found was that on such a thing you don't want to have square “boxes” for your cellular shapes, you want to have triangular ones, because a triangle is inherently mechanically stiff, whereas a square, unless you cross-brace all six faces, is not stiff. So we learned all about that on our smaller mirror building, so I thought: well, that1s interesting, I wonder how big a dish I could build? We had some NASA money. NASA was fairly generous in its support of our research at that time. There's an earlier stage here—let's just go back for a moment. Around 1963 (‘62 maybe) there came to be a major NASA effort here on the campus, of basic things, research in support of NASA endeavors, but not of specific missions. This included about six or eight people. It was the thing that brought Gerry Neugebauer to the campus. There were a lot of new appointments. Gerry Neugebauer, R. Vogt, Gordon Garmire, and some people who were already here, Leverett Davis, Bob Christy, (who is now the acting president of Cal Tech), and others, and I was the principal investigator at the suggestion of Bob Bacher. I guess it got up to be half a million or more dollars a year.

DeVorkin:

Did you have anything to do with actually bringing in the money, or was this something that was unsolicited?

Leighton:

We made a proposal to NASA. Bacher was the originator of the idea to do it, because he saw there was money available for educational institutions. And NASA, remember, under Jim Webb was trying to build space institutes allover the place. Chicago built a Space Institute, under John Simpson and so forth. We avoided the business of a Space Institute with a big building. We could have had a big space building right here on the campus, if we'd just said “Yes,” you know. But anyway, we saw an opportunity to move into fields which fit properly with the [field already studied here]. We were looking downstream—we could see that space activities would grow and that space experiments would become available, and would give us the techniques and the vehicles to do experiments in various fields, and that we ought to be active in some of those fields. So we built up quite an effort in a number of areas. I mentioned some of those. Infra-red astronomy, X-ray and gamma ray astronomy, the cosmic ray effort. (That was not an offshoot but a completely independent side effort, outside Vic Neher's cosmic ray work. Neher had been doing balloon studies of polar cosmic ray energy spectra, for a long time starting with Millikan's work.) Then there was theoretical astrophysics, with Christy1s pulsating stars, and stellar structure. There was magnetic fields, with Leighton L. Davis as investigator, and G. MUnch was in there, with astrophysics, and then we also started the activity that is now called the Astro-Electronics Lab, which now is at the Hale Observatories.

DeVorkin:

Are you involved with Astra-Electronics at an Administraive leve?

Leighton:

The Astro-Electronics Lab? No. I gave birth to it, in the sense that the proposal that was written covered all of these fields. It was like pulling teeth, but we intended that it be a single activity with these various components operating out of one fund. Actually, it quickly evolved into each investigator talking to his counterpart at NASA. NASA is such an organization that the people who are in charge of various areas are very jealous that “their money” doesn't get spent outside of their part of the mission. It was that way even then.

Leighton:

The lunar and planetary people always were more open and free, not with the amount of money so much, as with the interpretation of what constituted relevant research. Bless them.

DeVorkin:

This kind of philosophy seems to agree with the philosophy you had that NASA should support ground-based long range studies, that would aid in designing the space missions.

Leighton:

That's right. This was early '61, '62—

DeVorkin:

So was this mode of operation part of the proposal, that the people here on campus made to NASA?

Leighton:

That's right. As a matter of fact it was not a liberal response.

DeVorkin:

But it was a response.

Leighton:

It was a response. It was more or less what we asked for, but less, you know what I mean. And we felt we had a very good and scientifically credible team, to work on these areas. And we felt that, considering the magnitude of our resources, with the 200-inch telescope, and close connections with JPL and so forth, that really, we should have been able to make an effective contribution, much bigger than we ever were funded to do. I was on a number of advisory groups, advising on this mission and that mission—the eccentric solar probe, to get closer to the sun so you can take sharper pictures, and so forth. I explained to them that I thought you could take three times sharper pictures from the earth, next Tuesday, if you'd just put a slight amount of support in it. But they were willing to spend 150 million dollars, just on the chance that you could get closer to the sun and take close-ups. It's insane, really.

DeVorkin:

Was this what you might class as a government or a bureaucratic mentality, where they are existing for a certain purpose and they're going to support that purpose alone?

Leighton:

Well, it's not quite. There was a certain component of that. But what I found was that the organization was essentially a hardware-oriented, space mission oriented, space vehicle oriented thing. Even the unmanned part. The manned part was obviously this, of course. But they had a very narrow view. It was mostly run by engineers, to whom science is, you might say, just disorganized engineering. (Laughter) But they had very little appreciation of the value of knowledge. That's another one of the standard problems in my mind. That is, I think in this whole country, knowledge, scientific knowledge in particular, is under-valued; because, before you know something, you don't miss it, and so it has no value. You don't know what gold is under there. And if you don't know what's there, it isn't there; it might as well not be there. After you know something, it also has no value because, “Oh, that's well known, that's a fact, you know—so, what's new?” And so we always treat science in this country as if it were a cost, instead of an investment, an invaluable thing. And I think part of the trouble is that science is so much fun—it's immoral also: we're puritans at heart, and it's immoral to pay somebody just to do something that's fun. You know, the whole thing is sort of upside down—Congress and NSF and everything else, from that point of view.

DeVorkin:

But it seems as though some of the people in the government should have taken a tip from places like Bell Labs, that really do give tremendous credence to the value and the investment in pure research.

Leighton:

Bell Labs does that. Have you heard the story of Bell Lab, where, when somebody wants to build something, they say, “OK,” and he builds it, and maybe some money is expended, let's say some reasonable amount of money, and a year goes by, and you spend some more money, and another year goes by. No result. No papers, no nothing. And some boss up the line notices a little bit what's going on, and pretty soon there appears outside the fellow's office a telephone booth. Which is a subtle hint. There's the telephone booth. Nothing ever said. But there's a flurry of activity, out come the papers and the relevance of this to the overall mission of the phone company is explained carefully. (Laughter) It's a beautiful story.

DeVorkin:

It's a marvelous story.

Leighton:

So even the phone company has its mission, you know.

DeVorkin:

Absolutely.

Leighton:

We have a lot of stuff that Shannon and Pierce and people like that did, on information—it was recognized as being very much in Bell Lab's interest. Davisson and Germer were the only ones probably who really did something, with electron waves, that as yet has no known Bell Lab application.

DeVorkin:

No, it's the philosophy I think of dealing with organizations that are your only source for the major funding that is needed.

Leighton:

But a strange thing—the hardest I’ve ever worked for funding, ever, has been for this project we're now in. And just in the last few days, literally, we've received the good word, both from NSF and Kresge Foundation, that we’ll be in a position to build four of these telescopes.

DeVorkin:

NSF I can understand. How did Kresge Foundation get into it?

Leighton:

Well, starting two or three years ago, Harold Brown and Robert Christy, who was then provost, were pushed by our astronomers. Our astronomers had said some three years ago, that if we could bring off this millimeter telescope thing, that it would be probably the most significant thing instrumentally that we could do at Cal Tech, other than the upgrading and care and feeding of the 200-inch. And so I’ve had very good support on the campus, really excellent support.

DeVorkin:

Who supported you among the astronomers? You don't class yourself as an astronomer? Which astronomers supported you?

Leighton:

Virtually everybody who's in a position to have any opinion on the matter. There's Greenstein, Moffet of course in radio astronomy, Christy, who is physics, an astronomer, and so forth. Goldreich, a theoretician in planetary science, Neugebauer.

DeVorkin:

But the people who are directly involved with the 200-inch itself—it didn't mean that money would not go there?

Leighton:

No, we're not in competition. But it's a hunting license. As a result of the very strong support of astronomers for the idea, we had sent in our first proposal in 1973, in essentially the same form as it is now, although some details have slightly changed. Details about the design of the instrument, what exact instrument would we build— it’s virtually the same instrument, and it would have evolved into exactly what it is now, had we been going ahead on it full steam all the time. But anyway, in order to make that proposal for four instruments more attractive to NSF, because we were asking for a couple of million dollars, Brown and Christy were willing to go to the NSF people, and informally indicate that the Institute attached great importanace to this endeavor, and that if NSF saw fit to support the proposal, that Cal Tech would endeavor to raise, I think, three or four hundred thousand dollars, from private sources, to help build a building for the control center. That’s a very unusual step for the Institute.

DeVorkin:

In other words, it’s sort of a reverse on the matching grant situation.

Leighton:

Right. But nothing specific came out of that, in the sense that they didn’t say, “Hey, that’s a good idea, go ahead, and when you’ve got your money call us.” or something like that. They just said, “We’ll consider it.” At the operational level in NSF, this particular activity has always enjoyed, I think, good vibes and other feelings. But there it had the problem that there were a lot of other people who were just beginning to get interested in molecular millimeter wave studies. It’s a burgeoning activity, and almost the only millimeter dish in the world is the 30-foot at Kitt Peak.

DeVorkin:

Well, there are millimeter range dishes in this area. There’s Aerospace, with E. Epstein.

Leighton:

That’s right. Well, that’s a smaller dish. There were what we might call pioneering studies going on, and the importance of the field was becoming recognized. What I’m trying to say is that just at the time our proposal was submitted, there began a broad discussion by many people as to what kinds of new telescopes were needed. We proposed a millimeter-interferometer, NRAO decided they wanted to build a 25 meter dish. So there had to be discussion between the possible users. Do you want an interferometer? Do you want the big dish? And so on. Arguments. So things got messed up and delayed. Then, the Congressional investigations into the peer review business, and how the NSF really does it. Is there a group of back slapping cronies distributing the money to each other? And that kind of thing. And so NSF was forced, whether it was a good idea or not, to be very careful, waiting for a good long time, for all possible proposals to come in. They didn't solicit proposals for any particular thing, but they wanted to be sure that everybody who said he was thinking of a proposal along these lines would have a chance to put it in, and then all the proposals would be reviewed. And out of all that, by what I take to be their normal "alive and well peer review system," our project came out being one of two very high-ranking possibilities. Well, there was a third one, which was sort of taken away from consideration by a matching grant thing, because the Amherst Five-College dish found private support first. And they went in with some $400K I think, of private support, and said, “Look, we got this, if you can help us buy this telescope, then we're in business,” and so they got in first.

DeVorkin:

That did go through?

Leighton:

Oh yes. It's in existence. I haven't heard too much about it. I have my private worries about how well they can adjust the surfaces, since they do it by optical methods. I've looked at the surface and it is wavy.

DeVorkin:

Are they trying for the same tolerances that you have?

Leighton:

No. The company that built it talks about 50 microns RMS, but I think they've got more than that from what I've seen. But that's neither here nor there.

DeVorkin:

How big is that dish?

Leighton:

13 meter, I guess you'd call it. It's a fairly big dish.

DeVorkin:

That's only one dish, that's not an interferometer.

Leighton:

A single dish in a radome. They will get it down to about 2 millimeters. It is a very good dish, a fine dish for 2 millimeters. But our objective was to try to provide the dishes, which is the big expensive thing, for as high a frequency, as short a wave length, as you are ever going to measure from the earth's surface; to leapfrog over to that regime, and then discuss the question of receivers and things like that. Anyway, we had a lot of trouble, waiting and waiting, and in the meantime weld have to have a "band-aid" from NSF to help us finish the prototype dish and NASA would also help us finish that dish, and then we got a prototype mount from NSF, and it was sort of hand-to-mouth all the way. And it certainly took its toll, from me, in terms of all the new proposals, and replies to critics' comments, and the like. But now we’ve got a real green light, for three years, with assured funding, to build three telescopes. But a funny thing is, I was recently called by someone in connection with a Congressionally initiated study of the sources of funding for certain so-called key advances in various fields; the solar magnetism work that I did was taken as one of those. So I got called by some staff person. She asked what my source of funds was. I forget just how it went.

DeVorkin:

This is for the magnetic work?

Leighton:

For the magnetic work. And I told her it was ONR, and possibly (I had forgotten) AEC. And she asked whether, when we found out this thing about the oscillation and the super-granulation and everything, whether I noticed any change in my funding pattern in the next twelve months? I said, "No, I didn't." She said, "Thank you. Good bye." The thought was, they were trying to find out, you know, about whether funds that are solicited for a particular purpose are [used]. But I don't really know what the purpose of the whole question was.

DeVorkin:

When was this?

Leighton:

About two months ago. I was prepared to discuss, from the point of view of somebody who had been in funded research for a long time—not that I’ve gotten my own funds or anything, but I know what funds are, and I also know what constraints I felt, if any, about what fields I can go into, and where I can get money. Just the kinds of questions you were asking me. And I was prepared to tell them that the most productive things I have done were things for which I could not have foreseen the need—my desire. to do, my ability to do—far enough in advance to write a proposal, and wait for it to be acted upon, and then three years later or even 18 months, get funds to do it. If it had not been that I had the wherewithal at the time I got the idea, I would have not done the thing. And nobody seemed to be interested in that fact.

DeVorkin:

This is the sort of thing that runs against their grain. I mean, they really go on premeditation.

Leighton:

That's right. There was one fellow, I wonder where he is today? John T. Holloway, who was with NASA, in the very early days of our Cal Tech grant operations with NASA support, and he was instrumental in putting the packages together. He got the money from the Lunar and Planetary and from the astronomy and physics and particles and fields and all those different offices—put them into a big bundle, and put it together and shipped it to us. And he told me once, he said, “You know, I go crazy with these people in these various offices. They want to know exactly what you're going to do with their money. I keep telling them that neither I nor they can look over your shoulder and tell you what to do and direct you to what to do. If we can't select investigators in whom we can have some confidence, that they will take seriously the support we give them, and do something good with the money, we'd better not be in business, because we simply cannot second guess, and much less, plan ahead and tell you what to do or ask you.” I thought it was one of the most forward-looking statements. He left NASA shortly after.

DeVorkin:

And you don't know his whereabouts.

Leighton:

I don't know his whereabouts. I'd like to know, because he was one of the most brilliant people I came across. I came across some very nice other ones, you know what I mean—who have their heads on straight. Even Noel Hinners—I shouldn't say “even,”—especially Noel Hinners, who's the deputy administrator for NASA for science and applications. He gets very high marks when he's talking off the cuff. And he knows what you're thinking. He thinks the way you do. [Knock at door] He knows how people think about science, and he’s a good scientist himself, and yet he's also very high up in NASA, and somehow or other, they just have hammered into them that they cannot support ground-based work. For example, I was counting on NASA to continue to support the dishes for the interferometer. And out of a three million dollar effort, I was hoping I'd get $300,000 more from them—not a large amount for NASA. They put in some early things on the prototype, you know, God bless them, with the money we had from the other activity, which was freer and more open, and we got started on the thing. I don't think I could have even done as much as I did, had I had to say, “I've got an idea for building dishes,” and then write a proposal and say it's going to fit into such and such a mission, or maybe you're going to need dishes someday. I didn't know how well we could do. It had to be a “best effort” sort of thing. I was willing to risk my time and my own reputation, to whatever extent, and do the thing. But it's just a barrier. It would have been a barrier, if I hadn't had some money pretty much in the bank, that I could have devoted to it at the time.

DeVorkin:

How much effort did it take, or funding or time or whatever, to be able to see this improvement in the construction of the support system? Would you have been able to see that, if you hadn't had any support, financial support?

Leighton:

No. Those things, there's a dozen ways to do things. There's a lot of ways to put the skins on the panels and things, and we sort of got to one place at a time, and figured out how to do it, and in some cases, we actually backtracked and went in another direction. But we had had the other thing in mind all along, pretty much, and just decided, well, we won't do that any more, we’ll do this. And so it worked out. It's taken longer than I would like. On the other hand, we've also got into territory that is well enough beyond where the state of the art has been that we feel it's been worth it. But I could not have done that if I hadn't had money to start with.

DeVorkin:

Yes. Certainly. Now, you've been talking and implying that the project has been delayed, I guess because money was not as quickly available.

Leighton:

Yes, we could have had two or three instruments finished by now, if we had tooled up and done it.

DeVorkin:

But meanwhile, it seems as though you also are involved with a number of the other more conventional dishes, at the site, up at Owens Valley.

Leighton:

Not really, no. I haven't used those.

DeVorkin:

I’m thinking, in terms of the people that were talking to you last week, and there's no need to mention names, but when we were together at lunch, they were talking about applying for time. Was this on the millimeter dish?

Leighton:

On the millimeter system—yes.

DeVorkin:

Because they were talking about the Kitt Peak instrument also.

Leighton:

Yes, that's right.

DeVorkin:

Now, this kind of a problem, applying for time on a unique instrument which is not even finished yet, and now you're already being barraged with requests?

Leighton:

Not a barrage yet, but that was a substantial chunk of time, I guess I indicated, a whole month, right away.

DeVorkin:

Right.

Leighton:

11m not ready for my little brain child to go out in the world to that extent just yet.

DeVorkin:

What is this doing to science, the whole thing? It takes us to the point now where we're looking at the National Observatory, we're looking at national institutions, and saying, "Hell, there have to be people there to build these things. There have to be people there to maintain them. And they're so sophisticated that these people have to be the best people around. And yet we want everybody to be able to use them."

Leighton:

That's right.

DeVorkin:

This is almost a paradox.

Leighton:

It is. It is a paradox. And I guess I can toot the horn of the private institutions a little bit here, partly because that's my side of the thing. I would be on the other side maybe if I saw the other point of view a little bit better. But I think that it's true that, per dollar spent, both in optical astronomy and radio astronomy, that the mileage, scientific mileage, has been better, for the most part, in education or in university settings, than it has been in the National Observatories. Now, that's not to say that I think the National Observatories ought not to exist, much less that I think the money they spent could have been channeled into the other area. I think it's been probably a mutually beneficial thing, for there to be the National Observatories. But there has recently been, I think, considerable squeeze on the university arm of astronomy and, I think, already to the detriment, and in the future very much to the detriment, of the country, just in terms of the degree of thought and of foresight and so on, that it takes to build a new type of focal plane instrument. I’m here not talking about anything I’ve done or am interested in myself, but I’ve seen the development of image tubes and of multiplier systems, and scanning image tubes, digital data handling and so on. And while it's true that the big centralized places have made considerable contributions there, the contributions that they've made have in turn depended upon the existence of money available there to do these things, and from the point of view of many of us, the money has been spent without proper thought, for preassessment of the field and so on. I really don't want to get into too specific criticism here, because I don't really feel antagonistic, but I think that a lot of socalled engineering or performance work was done on a lot of different image tube varieties, things like that, without there being close enough coupling to the users, who are going to, in fact, take that to the telescope and use it. And as a result, the smaller activities, like Boksenburg over at Queens College, wherever it is, in England, who made a multi-channel photon counting spectrographic instrument, which he takes around and collaborates with astronomers on their telescopes. And here at a place without even a telescope—he can do things that you would have thought the National Observatory would have been right in there doing. Now, maybe they can’t cover all the waterfront. But you haven't heard that much about the organizationally big project results at the National Observatories. To the extent that Kitt Peak has been on the map in that respect, it’s because of a few individuals there, who are the analogues of the individuals here or at Lick or at other optical observatories, and the same with radio observatories, the NRAO. They just—I can't say they waste money, but their level of spending, it's Cadillacs, you know, compared to Model-T’s or something like that.

DeVorkin:

As far as the people who are making the contributions are concerned, the few people you say who are the analogues of the people here or at Lick, who are at Kitt Peak—those are the resident staff. Have you seen a good return for the investment in the visitors? Is that the aspect that you are questioning? As far as the prior thought, the fact that they are limited to the instrumentation that's there, or they have to bring their own instrumentation?

Leighton:

I can't speak so much about the NRAO Kitt Peak dish, the 36 foot dish, because I’ve not used it, and I realize that the receivers have been really up to state-of-the-art. I think that's where NRAO has made its contribution there. It hasn't been the instrument. The instrument is a very poor instrument, but the receivers have been pretty good receivers. But even there, at Bell Labs, Tom Philips has the hot electron bolometer which is a very good thing. And up at Berkeley, Townes and his group are working on a number of high frequency things, going on into the millimeter range and so on. No, my point really was that the National Observatories have enjoyed a pool of support which is not looked at year by year ahead of time, as to precisely what they're going to do with it. And in the view of many of us, have not used that pool of money very effectively in terms of visible output, in terms of the operation of the whole thing. The cost of telescopes of course—they've got excellent telescopes and things. That's fine, beautiful. But then, the engineering arm has been over-supported in some respects. In terms of science, it comes out. Rather than being, you might say, run by scientists for scientists on a shoestring basis, and then getting engineering done by outside people, when you want to duplicate something five times and put it in different observatories or something like that—rather than having their own built-in facility.

DeVorkin:

Do you think there's been enough time now to be able to look at Kitt Peak and analyze it in that way? Or do you have to look at it possibly on the basis that it's just barely finished its growth period?

Leighton:

That's possible. As I say, I don't mean to be antagonistic. It's only that I see my colleagues starting with really potentially superior instruments, major instruments, but for lack of just the seed money and the development money to do things even remotely comparable to what Kitt Peak can do. So it's a waste of facilities and everything like that. I mention this whole thing, not to criticize Kitt Peak so much as to criticize a system, namely our system of scientific support, which somehow, only if you are in a big organization can you find the kind of money, without infinite amounts of proposals and planning ahead and justification and that kind of thing. The red tape aspect of things, of churning out the proposals and defending them and all that kind of thing. Now, maybe the reason for that is that the number of hungry mouths is so great that the NSF and the others couldn't just say, “Well, OK, give them all—if they have no bread let them eat cake, give them all a lot of cake- ...” Because then, what do we do? We produce students, and students get PhD's and PhD's are hungry, and so—you know, it's a very complicated machine. But unfortunately what suffers is the science, per capita, however you want to put it, the total science output. And almost, I think, I advocate a kind of an elitism, a kind of a thing where people have to have a chance. Young people have to be supported. Some of us who are now old people were supported when we were young people, and under the umbrella of somebody who was somebody, like Carl Anderson. We didn't have to think about money. And that's the right way for it to be. Right now, we could bring in an assistant professor. We look at him from the point of view of what kind of ideas he has, is he going to be able to write proposals to support his research?

DeVorkin:

Well, that's totally different than it was.

Leighton:

Quite different. Oh, yes!

DeVorkin:

Let me turn over the tape.

Leighton:

I think the country loses, because of this need for the young staff to scramble for support. Now, many of them learn how to do that without really suffering, by letting the big boys do it for them, or something like that.

DeVorkin:

But it really makes the science turn into that sort of a thing we were talking about just a while ago—"If I don't make the observation now, somebody else will make it." In radio astronomy, I'm sure that's getting to be more and more true.

Leighton:

Yes. More and more true.

DeVorkin:

But they can't take the attitude, "Well, I’ll go and do something more creative, more individualistic.1I

Leighton:

It takes a lot of money even to exist these days—

DeVorkin:

Right. They have to make that observation, to survive.

Leighton:

Yes.

DeVorkin:

So what does that do to imagination and creativity in science? It looks like, the younger you are, either you have to be even more brilliant than ever, or lucky or whatever, or young people just can't be creative.

Leighton:

Well, I think that a factor in that is that in the past decade or two, we probably have produced more carbon copies of ourselves than was really justified by, you might say, the sensible use of any reasonable amount of money. We made more hungry mouths. And the Malthusian doctrine, whatever it is, is going to be there, however you do it. But I guess what 11m trying to appeal for is some component of scientific funding which is related to, perhaps, a vote or something like that, based upon perceived ability to do science.

DeVorkin:

For someone who's established?

Leighton:

You might call it institutional support. Maybe you could do it through schools. But of course, then you find the geographic distribution people saying: "Well, there's a place down in Alabama that really wants to be another University of California, and if we just gave them money, that's all it would take." There's some truth to that, in fact. But on the other hand, the various institutions are the product not just of the money that was put in, but of something about their board of trustees or regents and their administration. When Millikan came here, or whatever made UC great in high energy physics, and so on. Sproul. Some time down the stream, these people have left not only a capability in being to which others aspire, and should aspire, but also, a whole philosophy, a whole way of looking at things, in terms of how they handle the students and so on, that merits further support. And so I'm just saying, I don't think it ought to be that every Tuesday morning, we all go back to the wire and we all compete on an equal per capita basis for support, although there are people who would think you should, namely, the ones who are aspiring to get in. I don't know. It's hard to tell, and people who are at a place that has this good fortune to have a reputation and a considerable wherewithal and connections and that kind of thing—naturally, I would take that point of view, I see my own bias and the reason for it. and nonetheless, I think that it is a rational point of view, that has some bearing on how well this country does in its basic science. So, I don't know. That's all very philosophical.

DeVorkin:

But I'd be interested to know, and now we certainly can get up to the seventies, and talk about your membership on some of these important committees that do study which problems are the worthy problems to attack, and how to go about it—especially the Greenstein Committee, which you were a member of in 1970—

Leighton:

I don't think I was ever a member of it.

DeVorkin:

You were on the infra-red panel as of 1970.

Leighton:

Yes, that's right. That's when I got to be an administrator, and I dropped away from that. I was at the beginning heading up the infra-red panel, and got it going, but then, it constituted itself differently, because I wasn't able to really do that.

DeVorkin:

Well, were you involved enough in it at least to see that there was a very definite problem, in getting the funding agencies to understand the need to continue support for ground-based research? Or did you see possibly the committee itself being swayed to space research?

Leighton:

I don't recall having been close enough to the actual daily I operations of the thing to be able to answer your questions, or even I comment on whether I think they're reasonable questions. I think, if there's one subject that's left out, it's space astronomy, for example.1 I

DeVorkin:

Left out?

Leighton:

Very much left out. Yes.

DeVorkin:

By the Greenstein Committee?

Leighton:

Yes. It is mentioned only to the extent to say that they I didn't consider it. And it was assumed that there would be a program of space astronomy with its own motivations or something like that. I forget just how they said it. And that of that program, they regarded the Large Space Telescope as a primary priority object. But they did not put it in line with other things. And that's this whole ground-based versus space dichotomy. If you say, "Well, how much would it cost for that telescope? And if we could spend it on the ground, how would we spend it?" Well, you'd build observatories all over the place, you know. But then you wouldn't have a telescope up in space. And so the motivation for that has to come from other places, where you don't have to count the dollars against one or the other. And by the same token, if you say, “Well, it's costing so much to put that telescope there, we can't do any ground-based astronomy”—then of course, the astronomers wouldn't like that either, because they're just signing their own death warrant. So it's just an incommensurable thing. You just can't get people with that much conflict of interest to comment on the thing. And they did the best they could. I think they did a reasonably intelligent job.

DeVorkin:

The way you put it, 1 see it now in a different light, and would agree, that's right, they shouldn't have commented or made a big comparative statement. But to the casual person, and certainly to NSF or to NASA, they'd be looking very closely at what ground-based astronomers would be saying should be done, in the future.

Leighton:

Yes. Well, now, should there be an up-dating of the Greenstein Report, which there's some possibility of, 1 think it would be, not only to the point but absolutely mandatory that it deal with the question of the nature of ground-based astronomy, when the space telescope flies. Because ground-based astronomy is never going to be the same. Astronomers may not think that, but I think it's just going to be very different, in terms of the gradual buildup of such high resolution data, over much of the sky—you know, it's going to punch holes out farther, and fainter magnitudes and everything else. The kinds of questions that will be asked. And ground-based astronomers are going to be, at various places, processing space telescope data, not by direction from a center, but they're going to get their own ideas, and they're going to request information and get the pictures and process them. So the capability to handle those pictures, in whatever digital form they are, is going to be absolutely essential for ground-based workers. And there's been a report, as you know, about the Space Telescope Science Institute. But even before some of us came together on that, (I was on that study) we felt that there needn't be such a thing, but it's clear now that there does need to be such a thing. On the other hand, it has to be strong enough to be sure there's strong data support, data analysis support, but diffuse enough to be sure that it isn't the only place astronomy is getting done.

DeVorkin:

You're talking about this one large institute.

Leighton:

One large institute.

DeVorkin:

That basically controls the activities and the data reduction—

Leighton:

—of the space telescope. Not controls it, but coordinates it, let’s say.

DeVorkin:

I know that many people are talking about centers built around a PDS and a large digital computer that would basically be able to receive information from the LST and then analyze it for whatever purpose the projects were designed for.

Leighton:

Yes.

DeVorkin:

Are you saying that literally, every person is going to need equipment like that, in order to take advantage of the LST?

Leighton:

Not every person, but there has to be on the order of ten regional centers, area centers, that people can get to with sayan hourIs commuting time.

DeVorkin:

So you envision it as the Institute, set up with the LST—

Leighton:

And with data lines out to these "satellites," but with the satellites having local capabilities, able to do simple transformations on the digitized pictures. Not able to do complicated algorithms like linearizing the responsivity and stuff like that, but if you want to add elements, subtract elements, multiply them, move over a little bit, or something like that—the most elementary hardware arithmetic that you can do, parallel path or something like that, you’re going to need that. And you're going to need some data form, other than tape. These super high density tapes or something like that—so that you can actually store the pictures, you don't have to get them out of the central place, because that’s going to take a high data rate link too.

DeVorkin:

Right. Are you acting partly on the experience—this might be just an apocryphal story, that in the first few years of NRAO, they were gathering up so much taped information that they had a backlog, at least when I heard about this in the late sixties, early seventies, they had a backlog five or six years?

Leighton:

I never heard that, but that's interesting. I know the feeling.

DeVorkin:

This might be scuttlebutt, totally unfounded, but I’ve heard that NRAO had more data than they knew what to do with.

Leighton:

It's possible.

DeVorkin:

Are people worried about this with the LST? I call it the ST now.

Leighton:

Space Telescope, yes. I don't think so, for this reason. I think that the kind of data that will be there will be of such great value that it will be used. It will be catalogued and used. I think the problem with NRAO probably is—and there's a lot of space experiments also that have these characteristics—that only the people who proposed it and who got the original data either (a) understand it well enough to be able to reduce it and do all the massaging and everything, or (b) are committed to do it by the requirements—and are the only ones to whom it's of interest—whereas, with the Space Telescope, it will be quite different.

DeVorkin:

How about the serendipity mode with the Space Telescope? This is a very interesting idea. Who had that idea? Was it one person, or did it generally develop?

Leighton:

This is the business where they're always using the three minute field, no matter what else they're pointed at?

DeVorkin:

That's right.

Leighton:

Oh, I always took it as being an obvious thing. I didn't know that it was invented.

DeVorkin:

OK. That's good.

Leighton:

That's right, I think those pictures are going to be the biggest payoff.

DeVorkin:

It's going to change the way a lot of people are doing science. Certainly in the last five weeks, I've been sitting at a lot of tables, listening to a lot of people, and more and more people are talking about this mode, thinking about what they can do with it.

Leighton:

I'm sure of that.

DeVorkin:

Well, we spent a lot of your time, but I have one or two very important questions. Another thing that I've constantly been hearing at coffee conversations, that sort of thing, is the present situation at Kitt Peak, with the question of a new director there. And I'm sure scuttlebutt —it's not scuttlebutt any more, it's just that a lot of people have been asked and a lot of people have been turning down the job, the position, and it looks like it's a pretty grim situation. I'm not completely sure as to why. Now, we've been talking about Kitt Peak, and the efficacy of supporting a very large national organization that caters not only to a small nucleus but to hundreds and hundreds of visitors.

Leighton:

Yes.

DeVorkin:

Which has its value, there's no question about that.

Leighton:

Yes.

DeVorkin:

At a time when the established elite observatories are suffering, to a certain extent, from instrumentation lack and that sort of thing.

Leighton:

Yes.

DeVorkin:

What kind of a director is needed there, do you feel, and at a time when there is not a director chosen, so far as I know—and what do you know of the problem that you feel is significant?

Leighton:

Well, I've been on their Visiting Committee. Luckily I turned down an offer, or at least a serious feeler, for being the director, before they got Leo Goldberg. People came and visited me and everything like that. So anyway, I've been there in a certain sense. I've paid some attention to it, from the point of view of, how would I handle anything like that? That was just before I became the division chairman here, there was no connection between those—but luckily I had this local thing. I love Cal Tech very much. So I was happy that this other job came along and the other one was not pressed. But that was just about the same time, wasn't it? About 1970 or so.

DeVorkin:

Yes, it sounds right. You said something very quickly. Was there some sort of a statement of duties and expectations?

Leighton:

No. Anyway, I’ve been on their Visiting Committee. I've seen Cerro Tololo and I've seen the Kitt Peak operation and so on. I think the main criticisms that were made by the Visiting Committee when I was a member—they were not made specifically by me, but mainly by others who have had more organizational experience—was on the basis of cost accounting and looking at the true costs of things. Just along the lines I have mentioned, of the engineering efficiency, and what’s the real cost of the instrumentation, and so on. There was considerable suggestion that they could cut out an awful lot of fat and waste in their operation. That’s probably why I talk about it as if I know something about it. Because live heard at least the people who do know something about the managerial procedures and things.

DeVorkin:

Could you tell me who they are?

Leighton:

It's a Visiting Committee of some few years ago. There were a couple of people on it. I remember R. Giaconni, for example, and there was at least one other and live forgotten who it was, really. Bob Kraft or somebody. I’m not sure. But Giaconni was really quite active, and I think if you asked him, he'd say so now, about the problems that they had. And also about the cellular structure, into a solar department and a stellar department and an instrumentation department and so forth, with certain formal lines of communication. It did not seem to be optimally organized. And I think that Leo Goldberg made many of the changes that were recommended. But even at that time, there were repercussions from the Visiting Committee report, which was a very critical report. Had to be, because of the nature of the thing. And there were a lot of people whose little empires were shaken by this. There was considerable internal strife, I don't know about bloodletting, about the reorganization, under a better chain of command. And then there was this whole shoddy business about the secretary. There was one individual whose name I’ve even forgotten, mercifully, who was in the position of being the secretary of the AURA Board, and so was in on executive sessions when the director wasn't there. And he was administrative vice president or administrative director or whatever, nominally under the scientific director, but effectively, his powers were such that there was great strife between them, about operating the computer and the library and everything that seemed administrative, this other guy was supposed to handle. But then the organization evolved so it wasn't user-oriented, you know.

DeVorkin:

Was this an astronomer, in that position?

Leighton:

No, no indeed. He moved on, by invitation. There was a real bloodletting there. But I thought all that was behind them. I don't know of the recent situation. I just don't know of it. Greenstein knows, of course, very much. I have no feeling for it. I'm sorry to hear that they are still up in the air, on the position of the new director. We had our own problems here, of course, with Hale and Carnegie and Cal Tech. But it isn't anything like as bad as you seem to indicate Kitt Peak is. Talking about the new director and so forth.

DeVorkin:

At Carnegie?

Leighton:

No, at Hale Observatories. When Babcock retires.

DeVorkin:

What is the problem? Just choosing another man?

Leighton:

Well, that, plus the fact that the organization has suffered quite a bit administratively in the last two or three years. As I say, we have our own problems, let alone dirty linen and everything. But fortunately I'm not an optical astronomer by trade at the moment, and so I haven't been close to it. When I was in administration over here, I was dealing with the Cal Tech aspects of astronomy that were not specifically part of the Hale Observatories, and so I had some contact with Babcock, and there was a good deal of friction there. We're good friends scientifically, and once were personally. But he just, I don't know, suffered from that job. He never was cut out for it, and unfortunately he didn't see that soon enough to be able to let go of it gracefully. He should have been out of it five years ago, four years ago. But that's just one of those things.

DeVorkin:

Was it a legacy from his father or what?

Leighton:

His father was the nicest old man you ever saw. I don't know. I really can't say. But it's unfortunate, because I think part of our funding problem has come from a lack of imaginative direction—with a light touch. The trouble is that it's been, you can't do anything except through the Observatories, and you can't do it through the Observatories, so you can't do it. So we simply just ran around the ends and just did things.

DeVorkin:

What about dealing with Carnegie? You don't deal with Carnegie directly, since you're at Cal Tech?

Leighton:

That's right. I don't.

DeVorkin:

I don't know what the relationship is, as far as the structure of funding goes, and how the director of Hale Observatories is involved with Carnegie, but is it a possibility that Carnegie has now gotten sort of to the point of dictating what shall be built or what shall not be built or what?

Leighton:

No. I have a lot of specific objections to the legal document, on the basis of which the Observatories are operated, just simply on the basis that Horace Babcock has chosen to take a very legalistic, narrow view of what the intent is. If you have to do that, spell it out cleanly, then I think it ought to be spelled out differently. But if it were administered with a light touch, we could get along perfectly fine with the thing the way it is. I don't know to what extent his connections with Carnegie and the Carnegie trustees have been complicating factors. But it's a sticky situation. I just don't know. Fortunately, I haven't been close to it for the last couple of years. I’ve been happy to do my thing. So I’m without any very close connections there. I hear the scuttlebutt, and I know Maarten Schmidt's going to be the new director.

DeVorkin:

Yes.

Leighton:

But that's about as far as I go at the moment. And we're healthy here at Cal Tech. I think the Carnegie end of things is in pretty bad shape.

DeVorkin:

Why is that? Are they having just straight foundation problems?

Leighton:

I don't know. I think the Carnegie Institution is not very well off financially, and that of course the CARSO[10] thing has drained them down some, too.

DeVorkin:

CARSO?

Leighton:

The Southern Observatory, at Las Capanas.

DeVorkin:

Well, that's sort of what I was wondering about, because here is a new telescope, and everybody still says that the 100-inch and 200-inch need better instrumentation support.

Leighton:

Yes. Well, that whole thing started at a time when, had it gone according to the schedule at the time, it would have been an excellent thing. It was the right thing to do. Unfortunately, it got delayed. It got reduced. It got thrown out by the funding agencies. NASA and NSF were approached—for reasons I don't fully know. But at least at one time, the reason was that it was too much of a pure Carnegie operation, and they wondered where Cal Tech was then. And we were reluctant to go in with Carnegie, for reasons I don't know either, at that time.

DeVorkin:

But yet they went ahead.

Leighton:

If you're interested in that subject, I found that reading Helen Wright's book about George Ellery Hale, called EXPLORER OF THE UNIVERSE, was very illuminating, and if you start with the knowledge that there is to this day, highly visible to this day, in the editorial setup of the Report Of The Director and the Carnegie NEWSLETTER and everything else, wording which leaves the reader with the impression that the 200-inch telescope belongs to the Carnegie Institution of Washington—they're willing to leave that impression—and that the Hale Observatories is a department of the Carnegie Institution of Washington. And then you see the origins of that, in that book by Helen Wright, then you understand very much what makes Horace Babcock, and any possible jealous things between the Board of Trustees of Cal Tech and the Carnegie Institution and so on. It certainly enlightened me. Of course, now I can read into what I see an awful lot of that, where maybe it isn’t really there. But I’ve seen enough recent evidences that I think it's still very alive.

DeVorkin:

Yes. That’s a very interesting thing. I’m happy to say that that Helen will be working further at the Hale Observatories, organizing the papers in the attic. I just learned that in the last few days.

Leighton:

I see. That's good. I’m glad. I think she did a very balanced job on that. There is one thing, and it’s symptomatic of the thing that gets me right in here, with respect to Carnegie versus Cal Tech, and that is, and I mentioned it specifically to Horace Babcock—have you been up to Santa Barbara Street?

DeVorkin:

Yes, I’ve been there several times.

Leighton:

What does the sign say on their front?

DeVorkin:

Does it say "Hale Observatories?"

Leighton:

It says, "Hale Observatories: Carnegie Institution of Washington. II

DeVorkin:

Oh, really? OK. I haven’t looked at that.

Leighton:

Well, I’m glad you haven't seen it. I mean, to me, it's just a slap in the face.

DeVorkin:

That's the gold lettering in the new addition?

Leighton:

Yes. Well, out in front—on the front lawn, there's a big sign, big raised block letters, it says: “HALE OBSERVATORIES, CARNEGIE INSTITUTION OF WASHINGTON.” You see what I mean? There you are.

DeVorkin:

Yes. Well, then, it's still very much alive.

Leighton:

Yes, I suppose. Yes.

DeVorkin:

Well, I don't quite know where to go from here, except to thank you very much for your time.

Leighton:

OK.

[1](with C. Hsiao, E. W. Cowan, C. D. Anderson) Phys. Rev. 78 (1950) p. 290.

[2](with C. D. Anderson and A. J. Seriff) Phys. Rev. 75 (1949) p. 1432.

[3](with R. Noyes and G. Simon) Ap. J. 135 (1962) p. 474.

[4]Ap. J. (1959), 2; 366.

[5]Ann. Rev. Astron. Astroph. 1 (1963).

[6]Sacramento Peak Solar Observatory.

[7]The Sun (The Solar System Volume I. Chicago 1953).

[8](with G. Neugebauer and D. E. Martz) Ap. J. 142 (1965) p. 399.

[9]Seasonal darkening of temperate regions with melting of Martian Polar Caps.

[10]Carnegie Southern Observatory.

Session I | Session II