Walter Roberts - Session II

DeVorkin:

This is a second session oral history interview with Dr. Walter Orr Roberts, July 27th. Dr. Roberts, I'd like to begin by asking you about the historical significance of the Littrow spectrograph, especially R. W. Wood's involvement.

Roberts:

First of all, the spectrograph itself considerably predates the coronagraph. It was developed for use for use by Donald Menzel at an eclipse in the Soviet Union, which, if my memory is correct, was in 1935. There are some pictures somewhere, maybe at Harvard, of the spectrograph in use at the eclipse somewhere in Siberia.

He was accompanied, by the way, to that eclipse expedition by Gerasimovic, who was either then or later, the director of the Pulkovo Observatory near Leningrad. Menzel and, I believe, Menzel's wife Florence, and Gerasimovic and his wife were all on the eclipse expedition, together with a lot of other astronomers. My memory is that D'Azambuja from France and several others were there. Dr. and Madame D'Azambuja were both astronomers. Mrs. D'Azambuja was a terror.

She ran everything. My memory is that at the moment of eclipse she stood in the optical path and ruined the French observatory's image of the sun, but I won't swear to that! Anyway, Menzel became quite friendly towards Gerasimovic, and later Gerasimovic fell into political disfavor in the Stalin period, during the height of the Stalin repression in the late thirties, and he was exiled to Siberia. On the wall of the observatory, when I first visited Pulkovo, there was no picture of Gerasimovic, the director. He had been banished. He was a non-person. He didn't exist. The sequence had no break of directors, without Gerasimovic in it.

DeVorkin:

They just purged him.

Roberts:

They purged him. Many years later — this was now in the Khrushchev period — I was down one day in the Crimean Observatory in the south, in the library, where they had a lot of solar equipment, and I was there for a week or maybe ten days. I was sitting in the library one afternoon reading, and this little old lady came up to me, and she spoke pretty good English, and she said, "You don't know me, but I know you and I know your work. I am Mrs. Gerasimovic." And she told me the story of her husband being banished to Siberia to teach science in a small grade school in an extremely remote region, and he couldn't stand the rigors of the climate and he died.

But when I visited the Pulkovo Observatory the next time, about a year and a half later, Gerasimovic was right in there. He'd been reinstated. There he was, with his years of service as director of Pulkovo. There's been a lot of that. Gerasimovic also came to Harvard, I think the first year I was a graduate student, and gave a lecture, at Menzel's invitation.

DeVorkin:

In '39?

Roberts:

I think it was late 138 or early '39. It could even have been in '40, because I was there until July of '40. Anyway, the spectrograph went to that eclipse, and as I remem¬ber it, the observations were quite successful. I didn't have any real direct contact with the results of the expedition. But the spectrograph was in a warehouse at Cambridge, at Harvard, and Menzel decided that it would be a suitable spectrograph to use for the coronagraph, and I had the task of rehabilitating it and putting it to work.

DeVorkin:

This was the magnesium box?

Roberts:

Yes. I believe it was one of the first astronomical instruments ever to be built of magnesium. It was light enough for two people to carry quite easily.

DeVorkin:

That makes a big difference.

Roberts:

Yes. It was very light and extremely well designed. I don't know who designed it, but it was extremely well designed, although it was rather crude in its controls. I had to enhance the control section of it considerably for the coronagraph, because it had to be used every day instead of just once only. Menzel knew and I knew that the coronagraph didn't give very much light. It was a very low aperture, very long focus instrument, because of the need for the secondary optics and so on.

You need to get all the light you can in the spectrograph. Menzel was a friend of R.W. Wood, the famous grating maker. Wood was experimenting in those days with the blazed gratings that put a lot more light in a particular order of the spectrum. We got one of the first of the blazed gratings from R.W. Wood to use in the Climax spectrograph. I had to clean it two or three times, and so I noticed that it had his hand-engraved signature on the edge of the grating. I don't know where that grating is, but the guys are looking for it now.

DeVorkin:

So the original grating, when it was used for the eclipse, was not a Wood grating?

Roberts:

No.That was later, for the coronagraph. They used some other grating, I don't know what.

DeVorkin:

It was unblazed.

Roberts:

It was unblazed. Then I used the Wood grating until, I think, Richardson at Bausch and Lomb started making replica gratings, and these were even better and they were bigger. The R.W. Wood grating wasn't quite big enough to take the full aperture of the spectrum, and so I replaced the R.W. Wood grating with a Richardson replica grating a few years later. But for those first years, all those first photographs we used the Wood grating. By the way we have all the old gratings, all the old spectrograph plates.

DeVorkin:

Excellent.

Roberts:

I developed a sensitometer with my experience at Kodak in photography so that the plates were calibrated in relative terms. They were accurate from day 1 to the last day the spectrograph was used. You knew the relative brightness. You didn't know the abso¬lute brightness. But later, one of the guys at HAO developed a method of calibrating the scales, so we later knew the absolute brightness of the corona from those plates.

DeVorkin:

How much later was that?

Roberts:

That we did the absolute calibration? It was quite a bit later, for the IGY, because we discovered that all the different coronal stations were reporting wildly divergent intensities for the corona, and during the IGY we wanted accurate coronal data. So Richard Hansen, who was the chief observer at the Climax Observatory at that time, or maybe he was down here, I forget, but he was on the High Altitude Observatory staff, established the international standard for coronal intensity.

One of the weird things that turned out was that one of the Russian observatories was sending in lots and lots of observations, and they didn't agree with anybody else's observations. Hansen discovered this. It turned out, after an investigation, that they were fraudulent data. He was making up the observations, just looking at the sun's prominences, and he got fired from his job.

DeVorkin:

In Tashkent. The Russian.

Roberts:

Yes.

DeVorkin:

Let's go back to the spectrograph. How long was it in use here at HAO?

Roberts:

The spectrograph was used from 1940 till we built the new one, of a different design, in about 1958. That's my memory.

DeVorkin:

That's when the coronagraph went to Lockheed?

Roberts:

Yes, the coronagraph went to Lockheed. Not the spectro¬graph.

DeVorkin:

The spectrograph stayed here.

Roberts:

Yes, and the coronagraph got accidentally junked.

DeVorkin:

I believe we covered relatively well last session the construction of the coronagraph itself, the introduction of the optics, your reworking of the mounting and so on and so forth.

Roberts:

In that picture that's in the AMERICAN SCIENTIST, you can see that there are two optical paths. The first image of the sun is formed on a steel eclipsing disk right in the middle, near the axis of the telescope.

DeVorkin:

Do you have that paper here?

Roberts:

Here it is, yes.

DeVorkin:

I'd like a reference to that.

Roberts:

All right, that's page 39 of the AMERICAN SCIENTIST for 1952. It's from "Progress in Science" and it was later republished as a book. Right here is the main axis—you can see that wheel, and the telescope rotates around that point.

DeVorkin:

It's a very stubby fork.

Roberts:

Here, yes — a very stubby fork. The first lens is up here. That forms the eclipse right here at the axis. Then this goes down to the camera that takes the prominence pictures. That's a straight through system. Remember, I had to make something that was a box that you could open the covers on the top to get at the optics. That's this part here. These are just counter-weights to balance it. Then there's a crank over here that cranks up and down to focus. I said the eclipse was produced right at the axis — it's produced a few inches in front of the axis.

Then there's a mirror right at the axis that sends the light down another tube to the spectrograph down here, so it can be sent here or here, just by flipping that mirror in and out. Between pictures of the camera, we very often sent the light down to the spectrograph.

DeVorkin:

That mirror had to be adjusted for the declination of the sun.

Roberts:

Yes, every day.

DeVorkin:

You didn't have to adjust it during the day?

Roberts:

No, it didn't change that much.

DeVorkin:

The field was big enough.

Roberts:

Yes. That didn't affect the eclipse because the eclipse was occurring in front of that. All that did was change the position very slightly on the film, down here. That didn't do any harm.

DeVorkin:

What is the chance that you have the original photograph of the coronagraph?

Roberts:

I think that exists around here somewhere.

DeVorkin:

Okay, it would be nice to have that.

Roberts:

There were two or three others, this one looking at the spectrograph from that angle, but I don't know right offhand where to find them.

DeVorkin:

So this is AMERICAN SCIENTIST, reprinted as SCIENCE AND PROGRESS, Sigma Xi National Lectureships, 8th series, 1951-52. This is chapter 2, "Unsolved Problems of the Sun's Atmosphere."

Roberts:

I believe there's a schematic diagram, either just before or just after.

DeVorkin:

Here it is, yes, I see it. The Littrow was on a Coude kind of focus.

Roberts:

Yes, kind of a modified Coude.

DeVorkin:

Very good. I wish that whole machine was still in existence.

Roberts:

So do I. Harry Ramsay, who was responsible for its junk¬ing, has never gotten over it.

DeVorkin:

Oh, I've met him.

Roberts:

You've met Harry?

DeVorkin:

A long time ago.

Roberts:

Wonderful man, and to this day, every time he sees me, he looks guilty, because he was responsible for throwing the coronagraph into the junk heap.

DeVorkin:

I knew him when I was an undergraduate at UCLA. Ramsay got his training under you?

Roberts:

I believe so, yes, at HAO. He then later went out to Lockheed to establish the observatory.

DeVorkin:

Well, that would be an interesting thing. I'll be in LA.

Roberts:

That would have to be checked. I'm just saying it from memory, but I'm almost sure he came to work as an observer at Climax or at Sac Peak. One or the other. He lived at Sac Peak for several years, and that's when I was very, very active in running Sac Peak, along with Jack Evans. Jack Evans was my associate director at Climax and at HAO here, and then he was asked to be the first director at Sacramento Peak, after the split. We haven't come to the split yet between HAO and Harvard.

DeVorkin:

Exactly. Let's move then to talking about your perceived regard for the role of rocket astronomy, rocketry, in solar physics in the immediate post-World War II era.

Roberts:

Well, of course, I was tremendously excited by the potentialities of using the V-2s and subsequent rockets for upper atmosphere research. I established a lot of connections with Richard Tousey and Herb Friedman and I can't remember all the names now. There was a guy who was head of some interservice rocket panel, big shot in the rocket business, in the earliest days.

DeVorkin:

Toftoy?

Roberts:

No, but I knew him.

DeVorkin:

His assistant, Baine?

Roberts:

No.

DeVorkin:

Shotta? Military man?

Roberts:

No, he was a civilian, but he was head of a rocket panel.

DeVorkin:

Krause?

Roberts:

Krause. I knew him very well.

DeVorkin:

How did you meet Krause?

Roberts:

It was because of the corona, and I was involved in suggesting what kinds of experiments would be most useful to fly, in order to verify some things about the coronal temperatures and so on. I can't really remember in detail, but I used to visit with Krause quite frequently and also later with Marcus O'Day, of GRD, and also the director, Landsberg, and Milton Greenberg, who was also director at GRD. So, I got rather heavily involved, and I think Harvard also had some kind of contractual arrangements for rocket research. I used to go fairly frequently down to White Sands when the V-2s were being fired.

Then when we started searching for the Sacramento Peak Observatory, one of the conditions was that the observatory be on a site that had full surveillance of the range, so that we could coordinate the solar observations with the rocket observations, and also so we could use the site as a monitoring station. We had to have line of sight to the ground stations that were receiving data from the rockets. So that was one of the requirements that led to Sacramento Peak being chosen, its relationship to the rocket range.

I was in charge of doing the site survey, and there were two alternatives. One was White Mountain in California and one was in the Sacramento Mountains of New Mexico, what became Sacramento Peak. We surveyed four or five different sites in the Sacramento Mountains, and I made a couple of trips to the top of White Mountain. In fact, one day I got caught in a blizzard up there, the same day that an airplane crashed with a lot of scientists on board in the White Mountain region. There were some Navy people, ONR people on that flight. We were going up there under ONR, under Eugene Bollay, who was head of ONR, California, Pasadena office. Gene Bollay went up on the survey trip that day that the plane crashed, and I nearly froze my feet off on that trip, I remember.

DeVorkin:

Let me ask you about Krause and Tousey and also, did you ever consider designing a spectrograph to send up on a rocket?

Roberts:

No. I never did any rocket instrumentation design. But I was very close to the people who were doing it and used to talk with them frequently, especially Tousey.

DeVorkin:

Why didn't you want to participate actively yourself?

Roberts:

Well, because I was the only person in the country who had experience with coronagraphs and with the corona. It seemed to me a waste of talent to learn to do things in rocket flight, because we conceived of the corona research as integral and very essential to the measurement from outside the atmosphere by rockets, with rockets.

DeVorkin:

I recall that one of the early justifications for the Air Force supporting the pointing control business at the University of Colorado was that the Air Force wanted them to build a coronagraph.

Roberts:

That's right, a space coronagraph.

DeVorkin:

This was '46, '47? Something like that?

Roberts:

Yes, something like that.

DeVorkin:

Were you involved in that initially?

Roberts:

Yes, I was involved in discussing how to build the space coronagraph.

DeVorkin:

Who did you talk to?

Roberts:

The whole group here — William Pietenpol and William Rense and all of those people. I worked very closely with Harry Crawford, who was a mechanical designer. I think Harry Crawford later went to Kitt Peak. There was a guy named Hunter who was the business manager of what subsequently became Ball Brothers, and he actually engineered, if I remember it, the split-off between the physics department and the establishment of Ball Brothers.

DeVorkin:

That was later, in the fifties.

Roberts:

Yes, that was later in the fifties. I'm still talking about the late forties.

DeVorkin:

I was wondering, what was the pointing accuracy required for a coronagraph at that time?

Roberts:

Well, Jack Evans and I, mainly Jack but I played a role — I've even got the old research notebook —

DeVorkin:

I'd love to have a look at that —

Roberts:

— incorrect drawing in the design. We designed another kind of coronagraph called an externally occulted coronagraph, and that coronagraph allowed you to see a thousand or maybe 10,000 times fainter corona, because the objective lens was shaded by an artificial moon that was out in front of the eclipse. You had to have an artificial moon, then the objective lens, then the image, then the secondary system — in other words, have one more train of optics — and Jack and I built one of those out of plywood up at Climax in 1946, I think. We couldn't really make it big enough to work as a true coronagraph, but we realized that it had a tremendous virtue as a sky photometer.

We called it a visual sky photometer, because what you did is, you looked at the sky and you saw how bright the sky was, and you knew that you were measuring the scattered light from the atmosphere plus the corona. When you take a picture with an ordinary coronagraph, it's impossible to tell how much of the scattered light in the image comes from the objective lens and the dirty optics and how much comes from the atmosphere. You couldn't separate those two. This visual photometer gave us a way to separate those two.

We could measure the sky brightness separate from the instrumental brightness, because the new kind of spectrograph had a thousand times less instrumental scatter and therefore it was negligible compared to the sky scatter. Jack flew a visual sky photometer in an airplane from below sea level to I think 15,000 or 18,000 feet to see how the atmospheric transparency varied with height, right near the sun, and that instrument then was the prototype that became the coronagraph that we flew in the balloons, using Schwarzschild's, and then later that was the principal coronagraph in Skylab. Gordon Newkirk, who had joined our staff, took over from Jack and me as the principal user and designer and builder of those instruments.

DeVorkin:

Now, the sky photometer involved the externally occulting disk?

Roberts:

Yes, and so did those subsequent coronagraphs, and then, also, the principle of apodization was invented. That's something that I had never known about when I built the coronagraphs. It may have been known in optical principles but I didn't know it. That was first applied to a coronagraph, I believe, by my friend, M. N. Gnevyshev in Polkavo in Russia. He's been a friend of mine since late forties or early fifties, when we first corresponded, although I didn't meet him till later.

He became the principal coronagraph expert in the Soviet Union, and established the coronagraph station in Kislovodsk in the Caucassus Mountains. I visited him several times. So my portrait hangs in the observatory there. He developed this principle of apodization, which got rid of the diffraction around the first lens, and I think the diffraction from the first eclipse that's produced in a conventional coronagraph.

In any event, it decreased the instrumental scatter by an appreciable amount. Newkirk did this with a series of semi-transparent filters that were placed at the edge of the objective lens so that you didn't have a sharp edge to the objective lens, but it graded off with a specially designed rate of gradation. Newkirk realized that with the externally occulted coronagraph, you could do the apodization in a different way that would be far better.

You could either put a serrated edge to the artificial moon, or you could put three artificial moons separated by a few inches, and then one would diffract, and the next would diffract the diffraction, and the next, which would be the larger, would diffract the secondary diffraction, and so you reduced the scattered light by a much bigger fraction. That's the way the one in Skylab worked and the one on the balloon, shown down here in the lobby.

DeVorkin:

Using the serrated or the three?

Roberts:

Using the three. The serrated turned out to be hard to build.

DeVorkin:

Tousey's people used the serrated one.

Roberts:

Yes, they used the serrated one. Everybody suddenly realized the apodization at about the same time. It turned out it was a principle that had been known for a long time.

DeVorkin:

So this is early sixties that you're talking about with the triple disk and the sawtooth. Is this when it was first devised?

Roberts:

I think it was fifties.

DeVorkin:

I can check that. One thing I didn't realize is that apparently what you're after in space coronagraph studies is the far corona. Is this correct?

Roberts:

Well, no, we were after the near corona too, but you can't get it because of the apodization design, and because of the need to get to very, very low light levels, you have to sacrifice the inner corona. You can't see the inner corona.

DeVorkin:

I'm talking about the very first conceptual ideas that you had in the forties for sending something up on an Aerobee, before apodization and all of that sort of thing. Did this externally occulted disk design require less pointing accuracy? This is what I'm trying to get at.

Roberts:

Yes, it did. You see, we could do the original one just by cradling it in your arms. You could hold it, look into it and guide it accurately enough. You occulted maybe several minutes of arc instead of just a few seconds as you did with a conventional coronagraph. We had to guide the conventional coronagraph I'd say with five seconds accuracy or two seconds accuracy, whereas this thing was five minutes — so the pointing requirements were much less severe.

DeVorkin:

Did a coronagraph actually get built from the original AFCRL contract that was going to be put into a University of Colorado pointing control?

Roberts:

I don't think so. Bill Rense can tell you. But I think what was built was only a spectrograph.

DeVorkin:

That's right. I know of several spectrographs that he built, but not a coronagraph.

Roberts:

I don't think he built a coronagraph but I could be wrong.

DeVorkin:

Okay. When you wrote this original article, you said you were asked to provide guidelines or ideas for what could be studied by rocket shots.

Roberts:

Yes, but mainly in conferences, rather than in writing.

DeVorkin:

So could you give me some kind of a review of what you suggested and approximately when these conferences took place and where?

Roberts:

Well, first of all, Menzel was involved in all of them. I was sort of Menzel's junior associate. Menzel was the theoretician. I was the experimentalist. So a lot of the ideas were Menzel's, although I made a number of trips there without Menzel.

DeVorkin:

Is this to White Sands or Washington?

Roberts:

White Sands and also to Washington, and also to Cambridge. But I think we were speculating on what the X-ray spectrum would be, how strong it would be, all kinds of questions about what the optical depths would be. Also, we speculated on important questions about what to look for in the Lyman alpha and in the helium spectrum, I forget what you call the line but it's the helium equivalent of Lyman alpha, it's the fundamental line of the helium spectrum when it's partly ionized.

DeVorkin:

The helium II at 303?

Roberts:

Yes, that's right.

DeVorkin:

As far down as 303?

Roberts:

I think that's the line. It's the fundamental line of the hydrogen-like helium spectrum. We speculated about that. We speculated about what the continuum would look like. There were lots of conferences.

DeVorkin:

Do you remember the date range? Did they start in '45, '46?

Roberts:

Let's see. When did we first start firing the V-2s?

DeVorkin:

'46, in April.

Roberts:

Well, it was right around that period. It probably was the fall of '46 maybe or early '47. I know I had a visit from Russian astronomers in '46, to the Climax Observatory, and gave them designs. There's a point we forgot here. The Germans had built a whole bunch of coronagraphs, and during the late part of the war, and put one on a V-2, I think.

DeVorkin:

This is Kiepenheuer.

Roberts:

Right. They were being built in what is now the Russian zone. They were being built at the Zeiss works. That's at Jena. There was a very famous secret mission, headed by Georgi Dimitroff, who was the astronomer at the Harvard Observatory and also later at Dartmouth. They raced in to see if they could get the designs and maybe some of the optical components before the Russians occupied Jena, and they got there a day or so early, and brought out complete sets of the coronagraph designs. I went over those coronagraph designs, and discovered that just as the original coronagraph that Menzel had designed with Hobart French, it wouldn't work. When I visited Wendelstein with Menzel in '48, I found it was working, so somebody was smart enough, maybe Kiepenheuer, to recognize the error that was in the designs, and they modified it and then it was working as a proper coronagraph. But the design that Georgi Dimitroff picked up wouldn't have worked. That was an interesting point.

DeVorkin:

Did Dimitroff recognize that?

Roberts:

No, because he recognized what he was looking for, a coronagraph design, but it took me weeks to figure out exactly where the diaphragms were placed and so on, and to realize it wouldn't work as it was shown.

DeVorkin:

I see. That's fascinating. The Russians came here, you said in '46 to look at the coronagraph designs. Were they interested at all in the rocketry that was going on?

Roberts:

No, we didn't talk about it. As I remember, we didn't talk about it at all, except to indicate that some day, we would be doing astronomy from space. I don't think we talked about anything except how to build a coronagraph, and I gave them all of the designs that we were working on.

DeVorkin:

You gave the Russians all your coronagraph designs?

Roberts:

Yes. Jack and I were starting to design new coronagraphs for the postwar period, and we told them all the experience that we had gained using the old coronagraph, told them about the spar concept with all the optics on the outside, told them about the roller design so that you got rid of the backlash from gears. They came up with a gear design that got rid of the backlash also. They had a very outstanding optics lab in Pulkovo, and they built a coronagraph there, and acknowledged our support and help. That later led to the establishment of the coronal station in the Caucassus mountains, another one out near Tashkent, near Lake Baikal on the Mongolian border, and two or three others. Gnevyshev became the senior coronagraph man in the Soviet Union. Later they gave us the details of the new apodization technique they had developed- and which we had not.

DeVorkin:

Any idea whether they went to White Sands or were allowed to?

Roberts:

They went to Cloudcroft for a solar physics meeting held by Sacramento Peak and the Air Force, but it was not that early. It was some time in the fifties or sixties. They all went. I remember driving three of the Russians — we drove from Sac Peak to Boulder. One of them was A. B. Severny, who was director of the Crimean Astrophysical Observatory, and he was on that first trip to Climax in '46, and a guy named Melnikov, who died some years later, and a third one I can't remember. But I'm sure we didn't talk about rocket research in any detail.

DeVorkin:

We knew nothing about what was happening in Russian exploitation of the V-2s. We've only recently learned that they put spectrographs in V-2s but did so later, not as early as we did.

Roberts:

I remember once I talked to Severny and I asked him about what kind of photometers and spectrographs were being flown in rockets, and he looked at me and said, "You'll learn before I will."

DeVorkin:

When was that, any idea? Fifties?

Roberts:

No. I've been going to the USSR regularly since '58.

DeVorkin:

Okay, that sounds right. About your conferences with Menzel, who were the people, the racketeers or rocket scientists, you were talking to, and what was their reception to the ideas of the astronomers?

Roberts:

Well, as I remember it, we were just all very much excited about the potentialities together. I was with Tousey, Krause, Jim van Allen in lots of those meetings. I can't even remember where all of them were. It was a little peripheral to my primary interest and ability and function. But as you know, I became one of the founding members of the International Academy of Astronautics, and because of my close affiliation with all those people, I knew all the Russian ones. If I could look at the list again I would remember them. I worked with Russian ones and Hungarian ones and Bulgarian ones and French ones, worked closely with Dollfus and Roger Bonnet, and the man-wife team, Mr. and Mrs. Vassy.

DeVorkin:

This is all post-Sputnik, or was this IGY?

Roberts:

No, this was rocket research like Aerobees and things of that sort. Then in IGY they were all involved too, especially the Russian geomagnetician, Madame Troitskaya. I attended a meeting in '56 in Barcelona which was a pre-planning meeting for the ICY, and Sydney Chapman gave a major address and then a Russian whose name I can't remember gave a major address. That's when they said they were going to launch. John Hagen was there, I think. John was one of my close friends, and we were thinking about uses that we would make of the Vanguard.

DeVorkin:

How did you meet John Hagen?

Roberts:

He was a radio astronomer, and so I guess it was through solar radio astronomy. I was also very much interested in that field, as another way of getting at the sun's corona. I knew E.0. Hulburt, the director of NRL, very well. It was through him — now it's coming back to me — that we went on the 1952 eclipse expedition to Khartoum.

DeVorkin:

Through Hulburt?

Roberts:

Yes, through E.0. Hulburt, who was director of NRL at that time, '52, and with the help and encouragement of Tousey and the prodding of R. N. Thomas.

DeVorkin:

Hulburt was certainly one of the major superintendents.

Roberts:

Maybe he was retired as director about '52. But anyway we got a contract with ONR to do eclipse observations at the Khartoum eclipse in February of '52, if my memory's right.

DeVorkin:

That was described by many people as the first modern eclipse expedition.

Roberts:

Right.

DeVorkin:

Let me turn the tape over and ask you why it was called that.

DeVorkin:

Why was it called the first modern eclipse expedition?

Roberts:

I had not heard it called that so I don't know, but I can imagine why. First of all, our spectrograph was extraordinarily flexible compared to anything that had ever been done before. S.A. Mitchell was the only person who had tried to do the kind of sophisticated flash spectrum stuff that we did, except that we had ours calibrated so we could get absolute intensities and all that sort of stuff. We also had very rapid film transports, and we used electronic devices for timing and things of that sort. Moreover, it was a multi-institution expedition.

There was an NRL group and there was our group and there were three or four other different parties. Jack Evans had a terrible accident, from which he's still somewhat crippled, a few days before the eclipse. We were there for almost six weeks before the eclipse. He fell at night — he had to run the coronagraph at night to try to do some optical testing, because first of all it was so hot in the day and secondly, he needed the darkness to find the images. He fell off the telescope when somebody forgot to tie down the end of it and it started to swing, and he jumped off and hit the concrete on the way down and badly fractured his ankle — 20 pieces of bone or something. So he was laid up right up until the day of the eclipse, and his two assistants, Robert Lee and Robert Cooper, succeeded in finishing up.

They were there as mechanical and electronic experts, and they succeeded in doing the optical alignment and doing it perfectly, with Jack being there on a litter with a doctor sitting with him to make sure that he didn't over-exert. They did the alignments and got it going and it worked.

DeVorkin:

That's traumatic.

Roberts:

Yes. Excuse me — but it was partly through association with these people that I got interested in some of the kinds of sensing and observing that were being done, from NRL, from other groups, with rockets.

DeVorkin:

Okay, but that's 1952 through Hulburt.

Roberts:

Well, but that was the years preceding, because you see it took us about four years to prepare. So we were traveling back and forth, and not only negotiating contracts but talking science all the time, and I used to visit regularly at NRL in those days.

DeVorkin:

What did you think of the style of operation of some of the people doing rocket spectroscopy of the sun, such as Richard Tousey? How did you describe his early work?

Roberts:

There was Koomans also and several others. Well, it was just an inspiration to be with them. They were enthusiastic, excited. They spent practically all their waking hours talking about the potentialities, and it was a very clubbish sort of social, friendly atmosphere. I remember it as one of the happiest periods scientificially of my whole life, because everybody sort of had a common goal, and there were all these fantastic new techniques opening up, that we could see the potential of. It was a period of great blossoming and expansion of ideas, and yet, the groups were still small enough that you knew everybody.

DeVorkin:

Was there a sense of competition between the APL groups and the NRL groups?

Roberts:

Well, I guess so. I was mainly with ONR people and NRL people. Yes, I think there was, but I never sensed any hostility or antagonism. Just, everybody wanted to be first. Then the Vanguard began having such horrible troubles.

DeVorkin:

Oh yes, but that's much later. I'm still working on that early period.

Roberts:

Yes, that's true. I keep forgetting and merging them in my mind.

DeVorkin:

Fair enough. But during the early years, '46, '47, Spitzer and Goldberg got together, and got an ONR contract to form an astrophysical study group that would examine and advise on the type of science and type of solar physics being done with rocket spectrograms.

Roberts:

Right.

DeVorkin:

And one of their justifications was that they felt that the rocketry people weren't paying enough attention to the astrophysical problems themselves. Do you have any comment on that?

Roberts:

No, I don't remember that. I was so much up to my ears trying to get Sacramento Peak going. The ONR supported Climax, the Air Force supported Sac Peak, but we were designing the same instrument. We were going to build two versions of the same instrument. We actually were going to build two instruments for each place, and we did, subsequently.

DeVorkin:

The 16-inch?

Roberts:

Yes, and also the new small one, the new 8-inch. The 8-inch was always my favorite and the 16-inch was always Menzel's favorite.

DeVorkin:

Why so?

Roberts:

Well, I felt that going to a 16-inch was going beyond our capability too fast, and Menzel felt that this was an opportunity, with all the expansion of things, an opportunity to do the ultimate telescope right away. It nearly broke our backs, getting that 26 foot spar designed and working, but I must say Evans did an incredible job, and it still is working today, that spar that was designed way back then. The one at Climax has been discontinued.

DeVorkin:

That's what I recently heard.

Roberts:

The one at Climax was never fully exploited, but the 10 foot spar at Climax was a fabulous success.

DeVorkin:

Lyot was brought in.

Roberts:

Yes, Lyot came over in '46, and the most incredible coincidence, was Lyot's visit. Of course it was the first time that he and I had met face to face, and I think it was July of '46 that he came, and he spent several days at Climax and spent the whole time with me at the observatory. He was insisting that I should try to look at the disk of the sun with the coronagraph rather than concentrating strictly on corona and prominences.

DeVorkin:

Why was that?

Roberts:

Well, he said that you can use your birefringent filter to see solar flares, and I told him that I had done this many times and had never seen anything. One morning, after I had done the routine observations, he said, I want to see if we can see a solar flare on the disk." The largest flare that had ever been observed up to that time occurred while we were looking through the eye piece! We got photographs of a brilliant solar flare on the disk.

DeVorkin:

Is that the coincidence you referred to?

Roberts:

Yes.

DeVorkin:

The records I read indicated that Lyot came over to consult on the design and construction of the 16 inch telescopes.

Roberts:

Well, yes, it was the 16 and the 8, and the visual sky photometer, potentially the space coronagraph. All of that.

DeVorkin:

Oh, I see — on the visual sky photometer, so the visual sky photometer certainly pre-dated or was ...

Roberts:

I have in my notebook somewhere a drawing of the visual sky photometer which would date it. But I know it was before the end of the war — I'm almost sure — while I was up there at Climax. Then Jack showed me that my diagram was wrong, that it wouldn't work the way I'd shown it, but that it could be made to work. Somewhere I have that research notebook.

DeVorkin:

Do you have a copy of your proposal to do the space coronagraph too? Could that be in your papers at the archives?

Roberts:

I don't think so. Which space coronagraph? We first did the balloon coronagraph.

DeVorkin:

No, before that. In the forties.

Roberts:

Oh no. No. I shouldn't have called it a space coronagraph. We realized it could go up in an airplane, but we hadn't visualized explicitly putting that in a rocket. I don't think we did. It's conceivable that we did. But I'm sure we never made a proposal, because we never tried to do that.

DeVorkin:

So what was the origin of the AFCRL proposal or contract with the University of Colorado people to build a coronagraph that was on the Aerobee?

Roberts:

That was something that the physics group here, I think Bill Rense, decided to do, and I consulted with him about how you would do it, but I never played any part in writing the proposal or attempting to build it.

DeVorkin:

Okay, that clarifies that, good enough.

Roberts:

I worked closely with Rense and any ideas we had, we'd sit down and talk over. I'd see him frequently. But that was his idea.

DeVorkin:

Fine. Let's move in and concentrate on HAO, the development of Sac Peak. In the post-World War II period, what funding sources did you pursue?

Roberts:

In the post-World War period? Menzel did most of this. He got out of the Navy and went back to the observatory quite soon after the war, and he met Marcus O'Day and got O'Day excited about building a coronagraph station at Sacramento Peak, overlooking the White Sands. O'Day was I think number one scientist at GRD, and he was a rocket enthusiast, and a big operator, and so, through his help and with the help of a lot of other people, we got tentative indications of support from the Air Force to go ahead with building an extension of the Climax Observatory.

DeVorkin:

That's how it was first seen.

Roberts:

Yes, it was seen as another station of the Climax Observa¬tory. The High Altitude Observatory had been incorporated by then. It was incorporated in April of '46. Menzel was negotiating with the Air Force, and I was negotiating with the Navy with Menzel's help, to complete a postwar station at Climax. My principal interest was in the 8 inch coronagraph, and I got money from Research Corporation to build the 8 inch coronagraph. Menzel, with some help from me and through John Adkins and Charlie Palmer and Alan Waterman at ONR and all of those people, got money to build the 16 inch at Climax.

The Research Corporation, which is a private foundation, gave us the money first, and so Jack and I went like crazy to finish up the 10 foot design, 10 foot spar, and the 8 inch coronagraph, and I forget where we built that. I think we built that at Perkin-Elmer but I'm not sure. Oh no, we built the spar here in Colorado with a local engineering firm.

DeVorkin:

What was the name of that firm?

Roberts:

I think it was Silver Engineering Works but I'm not sure. Then we went ahead and Perkin-Elmer helped with the optics; they may have built all the optics, I'm not sure. By then they were making us extremely good coronagraph objectives, and Dick Perkin became a very close friend of mine, and got very excited and came out and visited and all that sort of stuff. Of course he was terribly interested in astronomy and in the Harvard Observatory.

Then, we located the site for Sacramento Peak, after these studies. I did the site studies including the sky transparency studies at both White Mountain and Sac Peak. Then we set up an expeditionary team living in a trailer consisting of Rudolf Cook and Leroy — whose last name I don't remember. Bruce Billings was quite substantially involved in those days. He was working on high speed spectrographs birefringent filter components and so on, at Baird Associates, Cambridge.

DeVorkin:

Baird was also building Tousey's spectrographs.

Roberts:

That's right, I'd forgotten that.

DeVorkin:

During the site survey period for Sac Peak, in the history of Sac Peak that I have, the Air Force history, a very short one, they indicated that there was an aerial site survey.

Roberts:

Yes. Menzel and I did an aerial site survey from an American Airlines Research aircraft with President Ralph Damon aboard, taking aerial photographs.

DeVorkin:

What was the research aircraft, a peculiar aircraft?

Roberts:

It was a DC-3 equipped with very good aerial photography capabilities, and so we photographed the whole Sacramento Peak area, and then were able from the photographs to get the distances to the various rocket launch points, and also, I think we made a topal map but I'm not sure. Maybe we had one already made. We had a Forest Service topal map.

DeVorkin:

This was the necessity of determining what would have the best surveillance points.

Roberts:

Of the rocket range. One of the requirements was that the observatory be at a place where you could survey all of the then designated rocket range stations, by line of sight.

DeVorkin:

That included Holloman as well.

Roberts:

Yes, it included Holloman.

DeVorkin:

Okay. Let me ask who pushed for the White Mountain site?

Roberts:

ONR, yes, and Eugene Bollay, the Pasadena office of ONR.

DeVorkin:

Why did they prefer White Mountain, any idea?

Roberts:

They wanted to build a medical research station, and Bollay really thought it would be a better site. Bollay thought it would be lower in scattered light. It was considerably higher in altitude, but the access was very difficult compared to Sac Peak.

DeVorkin:

Still is today.

Roberts:

Yes. The blizzard, and nearly freezing my feet, convinced me that the access was a major problem. We went up in Weasels in the middle of winter.

DeVorkin:

Okay. You mentioned the Research Corporation as one of your sources of funding. Was this a contact through Frenzel?

Roberts:

No, it was a contact of mine. I knew the Research Corporation people.

DeVorkin:

Was it Joseph Barker?

Roberts:

Yes, it was Joe Barker. Joe Barker became interested in me, and Joe Barker, let's see—there was some connection with Sigma Xi, I forget, but —

DeVorkin:

Yes, there was a Sigma Xi lecture in there somewhere.

Roberts:

Yes, and I did Sigma Xi lectures, I did some 50 of them. Joe was very much involved in getting me to do that. Sort of a quid pro quo for the grant. Not really, but rather something I did in gratitude for his help.

DeVorkin:

When was this?

Roberts:

'52. No, no, the grant for the coronagraph was much before that.

DeVorkin:

Yes, but you went back to the Research Corporation again in the early fifties for institutional support.

Roberts:

Yes. That's right. I've forgotten now, what year.

DeVorkin:

Well, it was something like 1950, where you later on identified in one of those biographical accounts that there were considerable funding problems for HAO at that time.

Roberts:

Oh yes. A real tough thing happened. The ONR had agreed to support the 26 foot coronagraph, 26 foot spar and 16 inch coronagraph, but we had to provide the building for it, the housing for it. It was about the time that there was a decentralization order given to the National Bureau of Standards, that it should decentralize from Washington, and the new IRPL, the CRPL, was one of the divisions that they decided they would decentralize. Menzel, through his friendship with Ed Condon, and later I with my friendship with Ed Condon, worked very hard on — see, by that time we had set up the High Altitude Observatory headquarters here at Boulder, jointly with the University of Colorado and Harvard University.

It was called the High Altitude Observatory of Harvard University and University of Colorado, and the presidents of the two universities served on the board. Then each president nominated two additional trustees, making a board of six, or maybe it was eight, I've forgotten, and that was the entity of the High Altitude Observatory. Now, we got into so much financial trouble trying ro build the postwar station at Climax. We had enough money to do the 26 foot spar, but not enough money for the building, and not enough money to do the small dome — we moved the small dome from the old site at Climax because the mine was expanding. The Climax Company moved that for us free, and set it up, and so it was operating with I think the old coronagraph.

DeVorkin:

Now, Climax and Fremont Pass, are they the same site?

Roberts:

Yes.

DeVorkin:

When you say moved, how far was it moved?

Roberts:

Five miles, from the area where the mine was expanding to an area northwest, where the wind was blowing, instead of off the mine, was blowing away from the site. I spent years studying that site. I used to go over there once a day in the afternoon, take the visual sky photometer, and see if the site was better, and it was. It was a few hundred feet lower than the original site where we had lived and worked.

We had so much trouble raising money. The Sacramento Peak funding was going ahead very successfully. The Air Force was willing to build the observatory, staff it with military people, build the 26 foot spar, and its dome, and build a small spar and its dome. The first contract with the Air Force was with the High Alti¬tude Observatory; it was not with Harvard. I was the project director and Jack Evans was my associate director. That involved first doing a site survey, and we set these two guys up on the mountain for a year in a trailer and they took daily observations with the visual sky photometer and also with a telescope to study the image steadiness, the seeing. This was to see how feasible it was to maintain the site, and how good the quality of the site was.

DeVorkin:

This was Billings and Cook?

Roberts:

No, this was Rudolph Cook and LeRoy something, that name I can't remember. They were working for me.

DeVorkin:

Yes, they were all working for you, but HAO wasn't being funded fully, you were having trouble.

Roberts:

Yes, we were having trouble with the funding to build the postwar station for HAO. All right, now the main problem was that we had to provide the money for the big dome, for the 26 foot spar. The Navy wasn't going to put up the money for that. Waterman and all the people, Urner Liddell and all the people at ONR were very friendly, but they couldn't raise the money for the building.

DeVorkin:

This was still before NSF.

Roberts:

Yes. Waterman was still at ONR. So, Menzel started negotiations with the Bureau of Standards, with Ed Condon, for them to take over the Climax station.

DeVorkin:

Oh, for them to take it over.

Roberts:

Yes, for it actually to become a government observatory, run by the Bureau of Standards. I told Menzel that I didn't want that, that if we had to give up our private non-profit status, that I would just simply drop out and go back to Kodak, because I still had a job at Kodak. Menzel and I finally made a deal, that if I could raise the money myself, build the big dome, the High Altitude Observatory could remain a private entity. And I did. I just went out and pounded the pavements in New York, and Joe Barker helped me. Max Schott, who was the former president of Climax, put up the first $5,000 towards building that dome, as a personal contribution. Then I met Alfred Loomis and he put up another $5,000, and I had 10, and so on.

DeVorkin:

I see. So you went to a lot of different sources. Corporate sources?

Roberts:

Oh, I went to hundreds of sources, e.g., the James Foundation; I spent two months a year in New York for three years trying to raise money.

DeVorkin:

That's why there are so many folders pertaining to large corporations such as TWA. Very interesting.

Roberts:

Yes.

DeVorkin:

What arguments did you use with them as to why they should fund the dome?

Roberts:

Well, that it was fundamental research related to radio communications and to weather. I was convinced by then of the weather connection, and I'd hired Dick Craig to work with me. I went to Harvard for one academic year, '47-'48, I think. I hired Dick Craig and David Hawkins to do work on sun-weather relationships, because I was going back now to C.G. Abbot's ideas of the recurrence of the drought. The drought of the thirties suggested the 22 year cycle and all that, and so, that's when I became very seriously interested in sun and weather, and I wrote a paper in SCIENTIFIC AMERICAN about it, way back in the early days, early fifties.

We set up a GRD with Bob White and Ralph Shapiro and Dick Craig. We set up what we called jokingly an International Geophysical Week, and we had a dry run of the IGY. I think the year that we chose as a dry run was August, '52, to see how you could collate data from all sources. That coincided with the big effect that I thought was a sun-weather relationship. Jerome Namias, who was head of the long range forecasting of the Weather Bureau, and Harry Wexler, chief of the Weather Bureau research, and a lot of other people got involved; Helmut Landsberg, all kinds of people.

We had about 50 or 60 people at that Inter¬national Geophysical Week seminar, and it turned out to be an International Geophysical Month. As we went on, we had a month of data. Anyway, that was the kind of argument I used for appropriations, and I got the money and we built the dome. But by then, some real sticky things had begun to happen. It was the McCarthy period, and I had been flying down to Sacramento Peak about ever,: ten days or so in an Air Force plane. The commanding officer of Lowry was a friend of mine named Colonel Wilson, I forget his rank, and he would fly me down in a DC-3 and then we'd spend the night on Sac Peak and then we'd fly back the next day.

Well, one day we landed at Holloman, and he got a call on the radio saying, was there a Dr. Roberts on board? That he had been denied security clearance and could not pass through the base to the outside unless they sent a paddy wagon with closed windows and drove me through. So the plane parked at the end of the runway, and Colonel Wilson and I got in the paddy wagon and drove outside the gate, where the guys from Sac Peak met me and took us both up to the observatory. Before I went through the security office, I went in and talked to the head of the security office, and he asked me a whole bunch of questions about my contacts with Russians and my loyalty to the United States and all kinds of things like that, and then the next day when we came back down to get on the airplane, nobody paid any attention to us.

We just went and got the airplane and flew off. About three weeks later, an Air Force officer arrived at my office here at the university – I was on the university campus then — and notified me formally that my security clearance had been withdrawn. No, no, beg your pardon, I've forgotten something. I had applied for a security clearance. My wartime security clearance had run out. I'd applied for a new security clearance, and that was the thing that was denied.

DeVorkin:

This was in the forties?

Roberts:

This was in the early fifties. Early fifties, and I had raised the money for the big dome at Climax. I think I'd raised it by then, I'm not sure — for the dome, the 26 foot spar.

DeVorkin:

So this was '51 or '52.

Roberts:

I think so. It's hard to remember the exact dates. But anyway, that security denial occurred, and to make a long story short, I contested the denial and was cleared in December of that year. I think that was '51 or '52. The transcript of the hearing is out there in those files.

DeVorkin:

In the University of Colorado archives.

Roberts:

Yes, I think so.

DeVorkin:

Were you told by this officer why you were being denied clearance?

Roberts:

He was very embarrassed and said he didn't know, but he said if I would request it, a formal statement of the charges would come, and so I requested it right then and there. Then it came, and it was incredibly vague. It said I had had association with known Communist organizations or Communist fronts. Then it named five organizations, two of which I'd never heard of.

DeVorkin:

What were the five, do you remember?

Roberts:

American-Soviet Friendship, American Youth for Democracy or something like that — I don't even remember them now. There were five.

DeVorkin:

Could the FAS have been one of them?

Roberts:

No. I don't think so. But I had attended a conference in New York called the Waldorf Conference, called a Scientific and Cultural Conference for World Peace. Harlow Shapley had run it, and I had been active on the committee setting it up, and the Russians attended, including Dmitri Shostakovich — I met him and spent part of a lovely day with Shostakovich. Then later, there had appeared in the House Committee on Un-American Activities a statement that a lecture had been given at that meeting by a self-avowed Communist, Richard 0. Bowyer; that it was not by chance that the following atomic scientists had participated in the meeting. Then it listed Albert Einstein, Willie Higginbotham, who was connected with the FAS — he was the founder of it, I think, or executive secretary, myself, Victor Weisskopf, and one other, I've forgotten who it was. Well, it turned out that not one of us had been at the meeting.

DeVorkin:

At the Waldorf?

Roberts:

No, at the meeting, the lecture by Richard 0. Bowyer, the self-avowed Communist.

DeVorkin:

This is another meeting?

Roberts:

No, it was one event of the big conference. We had all been at the big conference. But none of us had been at that session, even though that was the only thing we were charged with. So I got affidavits from each of them saying that they as well as I – I wrote one myself — had not attended it, and then tried to get the House Committee on Un-American Activities to retract the statement, because it was false, and I got everybody's agreement except Richard Nixon's. Richard Nixon refused.

DeVorkin:

Why did Nixon refuse?

Roberts:

Nixon said that he was so busy that he could only deal with questions from his own constituents, if you can believe that.

DeVorkin:

Lovely fellow.

Roberts:

Lovely fellow. Well, anyway, that was one of the things that appeared in my security hearing. Then a whole bunch of other things appeared at the security hearing that made absolutely no sense to me, including questions: "Did you invite three Russian scientists to visit the Climax Observatory in 1946?" I said, no, I hadn't, that my professor Donald Menzel had invited them, but I was glad to receive them. I had a lawyer and he had gone through all my papers, so I had the letter from Menzel asking me to do it, and I introduced that at the hearing. Little did I know that Menzel was in a security hearing. As I understood it, he had testified under oath that he had not invited them and that I had. And I had the letter, which I introduced. His hearing took three years.

DeVorkin:

Because of that?

Roberts:

Well, that and other things. He was very disorganized, didn't keep accurate files on anything. During that period and just prior to it, I told everybody in the world that I was having a security hearing, and got their help and letters, and even Robert McMath wrote me a letter. But Menzel didn't tell anybody. He didn't want people to think that he, a Navy commander, loyal American citizen, was being investigated. It turned out that lots of people were in the same boat as Menzel, and Shapley had had trouble, and the whole Harvard Observatory was regarded as a hotbed of radicals. Well, this is when the nasty stuff occurred. Ted Sterne had been pro-entrance into World War II and all the rest of the observatory had been against it — "let Europe settle its own problems." I was a pacifist at that time and had joined the Oxford Movement and all of that. Well, to make a long story short —

DeVorkin:

— don't make it too short.

Roberts:

Well, everybody got into the act, and a lot of bitterness occurred at the observatory.

DeVorkin:

You mean chastising Sterne?

Roberts:

No, Sterne was just a casualty of it. He was on the other side. He was in favor of getting into the war, and he got almost thrown out of the observatory by Shapley, for his attitudes towards the war, and that's when he went to Aberdeen Proving Grounds, as I understand it. I'm not sure about that. But I was on the Harvard Observatory Council that met regularly, and went over all affairs of the observatory, and the council began to be a confrontational and hostile thing, and Shapley and Menzel didn't get along well, at all, at that time.

Shapley had taken over running the observatory while Menzel was in the Navy during the war. When Menzel came back, Shapley appeared to be jealous of Menzel's re-assuming leadership. Shapley had been pro-Henry Wallace and Progressive Party, and Menzel had been against it, and all kinds of backbiting began to occur. I was working with Menzel, but having great trouble with Menzel — I felt Menzel was trying to turn the observatory over to the government and I didn't want that, and I was having terrible trouble raising that money.

I even went a period without salary to leave enough money to travel to raise the money. Took me quite a few years to raise that money, and it was delaying the construction of the observatory, and we had the obligation to the Office of Naval Research. We were afraid they would back out if we didn't get the dough, and Menzel wanted it to go into the Bureau of Standards, which I was opposed to. By the way, the Bureau, as a result of those negotiations, moved to Boulder. Really to be in association with the High Altitude Observatory. That's why CRPL is here and not somewhere else.

DeVorkin:

Really?

Roberts:

Yes. Ed Condon worked closely with the two strong Senators from Colorado. They were the two most powerful Senators then. That was "Big" Ed Johnson and Eugene Millikan, and so, it came here rather than the dozen other places that wanted it. That became the first big step in the growth of science in Colorado, in Boulder, and that was really because we had established the High Altitude Observatory here. The rocket research group in the university started from that.

DeVorkin:

Wait, the rocket research group started from —?

Roberts:

From the fact that the High Altitude Observatory had come here, and Menzel had come and talked to the physics people, and I had talked to them about building up a space capability and all of that. We all played a role in encouraging the president of the University of Colorado to be pro-science. His name was Robert L. Stearns. I got very close to Stearns and also his wartime substitute, Rueben Gustavson. Stearns was in the war and came back right after the war as president. He'd been president before. Gustavson filled in during the war.

DeVorkin:

I see, so it was Stearns that you had these discussions with?

Roberts:

Yes, and also Pietenpol and the physics department and Frank Walz and all of that, and a fellow who's still living but practically a recluse, alas — a physicist named James Broxon. He was really the only solid scientist in the university, in the physics department, in those days, and he worked on sunspots and cosmic rays. He had a cosmic ray counter in the basement of Mackey Auditorium, the big auditorium.

DeVorkin:

You say he wouldn't be able to talk to me, really?

Roberts:

I don't think so.

DeVorkin:

Just because of his age?

Roberts:

Age and bitterness. He feels he's just been left out of the world.

DeVorkin:

I've never seen his name appear in any of the rocket work. Why not?

Roberts:

No. He and Pietenpol were not on too friendly terms. But his research was good and was well known, and was respected by people like Bruno Rossi and Enrico Fermi and so on. I had Fermi come here and lecture, and one of the people they wanted to talk to was Broxon. I had the Astronomer Royal here to lecture and he talked to Broxon. So it started a great deal of ferment in science, and it was riding on that that the Pietenpol group, with Bill Rense and all of them, got excited and started the rocket project.

DeVorkin:

Rense came here in '49?

Roberts:

I think so.

DeVorkin:

So the group really started about then?

Roberts:

Yes.

DeVorkin:

Okay. That's very important for me to know because that certainly is one of the major groups in early rocket science, and knowing its origin is very important to me. The only person I will be talking to about that period, as of now, will be Rense.

Roberts:

Well, Rense is the key person to talk to, because his memory will be the best and the most reliable, and he did a lot of work down there at Holloman in those early days. He and I were very close friends and have remained so to this day. Now, coming back to Menzel...

DeVorkin:

You were talking primarily about Menzel and this nasty situation.

Roberts:

Yes. The situation got bad.

DeVorkin:

I know Dorrit Hoffleit was also not a pacifist, insofar as I think she also went to Aberdeen Proving Ground to work during the war.

Roberts:

That's right, she went.

DeVorkin:

Later on she went to White Sands.

Roberts:

Well, of course all of us changed our attitudes considerably with the war.

DeVorkin:

Shapley did too?

Roberts:

No, Shapley remained — well, Shapley got the label of being pro-Russian at the end of the war, because of his desire to eliminate nuclear war, and realization that it had to be done cooperatively with the Russians, and he also was rather extreme and I think a bit naive. I think he got used by some people in the Communist Party here in the U. S.

I remember, I had one episode in which I was called by somebody, a man named Dan Gilmore, who told me that Shapley had asked me to do something or other. Dan Gilmore was on the staff for this Waldorf Conference. So I immediately called Shapley, and Shapley didn't know anything about it. So I figured something's going on here. Then I had a meeting down in Denver and a small group came in and tried to rewrite a petition that I had written, for negotiations with the Russians to prevent nuclear development. It was to support the Baruch Plan. I gave a speech in 1946 on nuclear war which was carried all over the nation on the radio. I have copies of that.

So I was very active, speaking all over the state against nuclear war. I was part of that movement of atomic scientists to prevent nuclear war, and I fought very hard for the McMahon Bill and the Baruch Plan, joined the United World Federalists, became a close friend of Norman Cousins, and so on.

DeVorkin:

Was your desire to keep HAO private seen as being something questionable by the Un-American Activities people?

Roberts:

No. No, that never entered. It was only that Menzel didn't think it could be done, just thought it was impractical to try to raise the money from private sources. He hadn't had much luck raising money from private sources. I just didn't want to be a government lab and civil servant and all that. Probably a prejudice but anyway, that was my feeling.

DeVorkin:

That was independent of the nasty business.

Roberts:

That's right, that was independent of the nasty business. That was not a source. The security stuff was the whole source of the nasty business, and disagreements on politics, of how to deal with the Russians. Sterne was very anti-Russian and Shapley was very pro-Russian. Menzel was sort of pro-Russian but Shapley started to — I hate to say this, but he would tell one person one thing and another person another thing and put them at odds. He was putting Menzel and me at odds with each other.

DeVorkin:

In the postwar period.

Roberts:

Yes, in the postwar period.

DeVorkin:

You had no indication that he did any of that in the pre-war period?

Roberts:

I think he probably did. Yes, I think so.

DeVorkin:

This has been a general recollection of people at Harvard about how Shapley actually governed and kept his superstars.

Roberts:

He governed by dividing and by creating tensions. It was hard for me to realize, but I think that's true, and it was sad, because there were so many things that were magnificent about him and the Harvard Observatory. I've always prided myself on running a happy ship. And much of running a happy ship, I learned from him.

DeVorkin:

Isn't that peculiar.

Roberts:

Yes. Well, anyway, one day, Menzel and Marcus O'Day and I were down at White Sands, and we had breakfast, and O'Day said to Menzel that there had been rumored serious problems with security regarding this Harvard group.

DeVorkin:

'51, '52.

Roberts:

Yes. I don't remember exactly when. It was standing in the way of successful negotiations with the Air Force, and then, I think that was the day we did the site survey for Sac Peak.

DeVorkin:

Well, Sac Peak started really in '47.

Roberts:

This was all before the security hearings and so on.

DeVorkin:

So it wasn't '51, '52.

Roberts:

No, I really can't keep clear in my mind the dates.

DeVorkin:

Okay, but it was in that period.

Roberts:

It was in that period, and it was after I'd been to the Waldorf Conference and I think that was '48. So afterwards, after we had left O'Day, Menzel talked to me and said, the only solution is for me to resign.

DeVorkin:

For you to resign?

Roberts:

For me to resign, from the project and from the observa¬tory.

DeVorkin:

This was because of your security problems, not because of Menzel's?

Roberts:

Apparently. I don't know if his security problems had started or not, but he was apparently of the impression that I had invited those Russians to Climax, and that I had given away to them all our knowledge and so forth. He also was antagonistic toward Shapley for that Waldorf Conference, and I had attended the Waldorf Conference.

DeVorkin:

And Menzel had not?

Roberts:

Menzel had boycotted it. So he asked me to resign.

DeVorkin:

He did ask you?

Roberts:

Yes. I was, needless to say, terribly upset, and I came back and went to talk immediately to the chairman of our board of trustees, who is the chief justice of the Colorado Supreme Court. His name is William S. Jackson. Jackson was outraged too, and he said, "Menzel can't fire you. Only the trustees can fire you." That led to my staying, and the trustees talking to Menzel. I never knew exactly what the trustees said to Menzel, but I wasn't fired. And thereupon began the separation of Harvard from the High Altitude Observatory. Now, McGeorge Bundy was then one of the trustees. He was not yet president of Harvard. He was provost. The provost of Harvard always represented the president at the board meetings in Colorado. Bundy, seeing the tensions and the problems in the observatory, recommended the separation of Harvard from the High Altitude Observatory, and that occurred.

DeVorkin:

Did Menzel object?

Roberts:

The split resulted in Harvard taking responsibility for Sac Peak and HAO taking responsibility for Climax, so that we were working with the Navy and he was working with the Air Force. I still had to run the place, even though I wasn't administratively responsible, because I was the one who knew how to do it. That's when they chose Jack Evans to go.

DeVorkin:

That was September of '52 he became director.

Roberts:

Jack and I, you see, were intimate friends and have been all our lives, still are.

DeVorkin:

So there was no sense of competition between Sac Peak and HAO.

Roberts:

Never. We've always worked cooperatively.

DeVorkin:

So it was purely the security business that actually separated them.

Roberts:

Yes.

DeVorkin:

Fascinating. That's really fascinating.

Roberts:

The interesting thing was that the High Altitude Observatory trustees, every one of the Harvard appointees remained as a trustee. They were serving in their individual capacity and they refused to resign. So I had the same board. I had exactly the same board.

DeVorkin:

And you didn't want them to resign.

Roberts:

No, I didn't want them to. Judge Jackson was appointed by Harvard.

DeVorkin:

Oh, he was appointed by Harvard? I thought you would have gone to the Colorado people.

Roberts:

He was the chairman. John L. J. Hart was another Harvard trustee, and he is still emeritus trustee of UCAR. He's never terminated his connection to this day, even though he's 83 years, I think. Judge Jackson never terminated it until he died. So I had total, complete support from the board, and then they got busy helping me raise money, and that's when the observatory really began to go forward and blossom. That's when I got all that corporate support for the Institute for Solar-Terrestrial Research. That's why there's a Damon Room here for Ralph Damon, president of TWA, and all of that. I became a fund raiser. That all stemmed from that security trouble. Now, it turned out later that I found out that Menzel had had terrible security clearance problems.

DeVorkin:

Why?

Roberts:

It's hard to understand how a person so innocent of any subversion could have gotten involved in what I have heard was a three year security clearance. But you see, he had done things, like that business about the letters. He testified under oath falsely. He had testified that he had never sent any contributions to certain organizations, and they produced a check showing that he had done it. I do not know this directly — people have since told me of it.

DeVorkin:

Was it his memory, he didn't remember?

Roberts:

It was his memory. He was absolutely without reliable memory and he didn't keep any paper. He threw everything away. I keep everything.

DeVorkin:

Which is great – for more reasons than one, obviously, as we're talking. But that's incredible. Then that was probably the source of his problem?

Roberts:

I think so. He had made a contribution to the Spanish Loyalist cause, and also forgotten that. But he was a totally loyal American citizen and his anguish was a tragedy and injustice.

DeVorkin:

How closely did you follow Shapley's involvements in hearings?

Roberts:

Not very closely. I had come to the realization, sadly, as a result of serving in the Council, that Shapley was doing a lot of what I guess I'd call dirty tricks, and I distanced myself from Shapley, although trying to retain my personal affection for him. Then he later moved here to Boulder.

DeVorkin:

Oh, he did?

Roberts:

He died here in Boulder.

DeVorkin:

I didn't realize that.

Roberts:

Yeah. His son lives here, Alan.

DeVorkin:

Alan Shapley, one of his sons.

Roberts:

Alan has been throughout that period one of my closest friends, and my former secretary is Alan's wife, who worked for me through all the security stuff. My entire staff volunteered to work free as much as possible to help me with my security thing.

DeVorkin:

Marvelous. Would it make any problems between you and Alan Shapley?

Roberts:

No, never. Alan I think knew his father's problems too, and it was just a sad thing for all of us. Then in his later years he became very senile. I have never talked in detail about this with Alan.

DeVorkin:

Harlow Shapley did?

Roberts:

Harlow did. Yes. He'd have flashes of his old brightness, but most of the time he just — you know.

DeVorkin:

But he lived to a very great age.

Roberts:

Yes, he did, and his wife Martha also. She died just a couple of years ago.

DeVorkin:

I didn't realize that.

Roberts:

Yes. She lived in a nursing home here for ten years and then moved down with their daughter in Tucson, I think.

DeVorkin:

Do you have any comments on the effects of the security problems on Shapley's personal style, on the course and progress of the Harvard College Observatory?

Roberts:

Oh, I think it produced severe disruption, and internal strife, and Shapley had a streak of arrogance in him, and he would make provocative statements about the House Committee on Un-American Activities, which he called the "Un-American Committee." He was very proud of his defiance, and he'd always tell people loudly of his defiance of the committee. It created a lot of internal strife. Later, in the late fifties — now, I had become a friend of Alfred Loomis — Rowan Gaither, who is one of Loomis' closest friends, asked me to serve on the Mitre Corporation founding board.

Gaither wrote a famous secret report, called the Gaither Report, on the future of research and so on in the military, with the main emphasis on the Air Force. It called for the creation of, out of Lincoln Labs, some separate research entities, one of which became the "Mitre Corporation. He wanted me to serve on the founding board of Mitre. Well, I didn't tell you all the stories about getting my security clearance.

DeVorkin:

You finally got it back.

Roberts:

I got it quickly, got it in three months. I didn't get it back, because it was a new clearance, but the funny part of it was that I had requested the clearance in order to pass through Holloman, through a classified area. Then it became unclassified and I had no more need to know, so one of the tough problems was establishing that I had a need to know. So all of my work in the rocket research and so on became one of the reasons I had a need to know, and Hulburt and Friedman and all those people testified that I was a leading scientist with a need to know.

DeVorkin:

That's how you got it?

Roberts:

That's how I got it. But then when I decided to join the Mitre Corporation board, I had to get a much higher clearance, the highest clearance, and we were having trouble with it. It wasn't being denied and it wasn't being granted. So the chief of security of Mitre Corporation, Tom Grady, came out here to Boulder and spent a month, and he went through every bit of my paper. I had been very active in the postwar period in trying to get the nuclear—all of that. I was a friend of Szilard's and Fermi's; I worked with Teller. Teller, who was originally for the Union Now with England, headed by Clarence Streit, wanted England and the United States to become a single nation. I went down to Los Alamos to give political lectures at Teller's invitation, if you can believe it.

DeVorkin:

Even if you didn't agree with his position.

Roberts:

That hadn't hit me. I also knew Oppenheimer very well. I attended a couple of conferences with Oppenheimer. I found Oppenheimer much like Shapley, devious and arrogant and so on, but also of course I had no doubt of his genius and his dedication. Anyway, Brady found a letter that I had totally forgotten in my files from the Carnegie Corporation. I had applied to the Carnegie Foundation for some money for the observatory, and there was a letter saying that they couldn't consider making a grant till I'd paid my bad debt that I'd never paid back for a graduate school loan. But I had never made a graduate school loan, and it turned out that there was a guy named Walter R. Roberts who had lived in Boulder, who was reputed to be a member of the Communist Party!

DeVorkin:

Oh no!

Roberts:

Yes. That's what they finally found out. When they got all that straightened out, I got my top clearance.

DeVorkin:

What about the loan?

Roberts:

He had the loan. Even the Carnegie Corporation made a mistake. So then Grady figured, "I'll bet the FBI made a mistake," and then somehow, I've never learned how, he got access to my FBI files. Then suddenly all those questions of my security hearing came out. I realized that they were connected with that guy, and not with me. But I didn't know that guy then and didn't realize why a day and a half of questions were asked of me, none of which were relevant to me.

DeVorkin:

Did You ever meet this Walter R. Roberts?

Roberts:

No. I used to get girl friends of his, calling me up asking for a date, and I'd always thought it was a prank.

DeVorkin:

You never connected it until...

Roberts:

Never connected it until Mr. Grady.

DeVorkin:

Well, Tom Grady must be a very good friend of yours.

Roberts:

Unfortunately the poor guy died two years later. He was a lovely man.

DeVorkin:

Amazing. Also quite a thorough researcher. That's important. That's quite a fascinating story, and it explains the separation of the observatories. It explains a lot. It's very very interesting.

Roberts:

And I do want to emphasize that even to this day, High Altitude Observatory has staff at Sacramento Peak, and when we finally closed the observatory at Climax and moved the K coronameter to Hawaii ...

DeVorkin:

K coronameter?

Roberts:

It's a different coronagraph. We developed still another kind of coronagraph.

DeVorkin:

What does the K stand for?

Roberts:

The corona has three components. One of them is the K corona. We developed an instrument to observe the K corona by means of its polarization. This gave us another factor of 1000 or 100,000 in sensitivity, because the sky light is not polarized that way. Beginning in the mid-fifties we developed a K coronameter, and that was done by two or three people on our staff, including Gordon Newkirk again. That was what we moved to Hawaii, operating it first at the Mees Observatory, and then building our own station on Mauna Loa, when it became clear that the weather situation at Climax just couldn't justify operating at Climax any more. We got three times more clear hours in Hawaii than we did at Climax.

DeVorkin:

Had it deteriorated?

Roberts:

No, it was just that in the early days, the access was the governing situation, and we put up with bad weather because we could get there. Then when you could easily get to the summit of Mauna Loa, you knew that you had a far superior site. By then Sacramento Peak had so much going, and it had better weather. One of the main reasons that I argued for the use of Sacramento Peak was that it had nearly twice as much clear weather as Climax. So we moved everything either to Sacramento Peak or to Hawaii, and then closed down Climax.

DeVorkin:

Quite recently.

Roberts:

Yes, eight years ago.

DeVorkin:

So nothing's left at Climax?

Roberts:

Except the buildings.

DeVorkin:

Are they being used for anything?

Roberts:

Fertilizer is being stored by the Forest Service in that one, and one is empty.

DeVorkin:

Did the small dome house the original coronagraph?

Roberts:

Yes.

DeVorkin:

I would like to put on the record that I hope that building will be preserved as an historical site.

Roberts:

Well, that's interesting. It sits there just absolutely idle today.

DeVorkin:

Are you in control of it or is the Forest Service?

Roberts:

No, we turned it back to the Climax Company. The Climax Company gave us an acre of ground. The Climax Company is now closed. Climax mine is closed. So that sits on Forest Service land.

DeVorkin:

It would be someone in the Forest Service who we'd talk to about preserving that building.

Roberts:

One house was moved to Leadville, but the old Butler Building from World War II still sits there.

DeVorkin:

On the original site?

Roberts:

No, on this site.

DeVorkin:

So everything was moved from the original site?

Roberts:

The old original site is now down inside the mine itself.

DeVorkin:

Inside the mine?

Roberts:

Sure. The Glory Hole extends all the way out to where the observatory used to be.

DeVorkin:

You called it a Glory Hole?

Roberts:

Yes.

DeVorkin:

What's that term mean?

Roberts:

Well, Glory Hole is a form of mining where you go in underneath, and draw out the ore, and then it caves to the surface, and as that hole expands, it expanded to encompass the observatory.

DeVorkin:

No wonder you had to move. There's no way to preserve that site.

Roberts:

No.

DeVorkin:

But there is a way to preserve the building.

Roberts:

Yes.

DeVorkin:

Presumably we would talk to the Forest Service about it.

Roberts:

Yes. Either that or the Climax Company. I think the Climax Company still has jurisdiction over that piece of Forest Service land. They have a long term lease for mineral rights.

DeVorkin:

Okay. So that answers that question about the closing of the observatory. Let's talk a moment about the various reasons for moving HAO administratively to Boulder. Were you the person who made that decision?

Roberts:

No, Menzel and I made that jointly.

DeVorkin:

What were the reasons?

Roberts:

Well, we realized that we wanted to build a much stronger theoretical group associated with the observing station, and a mining community, with all of the hardships and so on, was no place to try it. We wanted affiliation with a physics department and a university, and we approached the University of Denver and the University of Colorado jointly. First we thought of moving it back to Harvard, but we decided the distance was really an obstacle, so we decided we'd try to find the nearest association we could, and the University of Denver had an excellent cosmic ray research program under a guy named Byron Cohen and his wife. They were both on the staff. Her name was Essie White Cohen.

We approached them, and also we approached either Stearns or Gustavson, I can't remember, from the University of Colorado. We decided to make a three-way observatory, Harvard, Denver and Colorado, and locate it on either the Denver campus or the Boulder campus. Well, for legal reasons the University of Denver couldn't do it.

DeVorkin:

The Cohens wanted it?

Roberts:

The Cohens wanted it and the president wanted it but the lawyers advised against it, and so, we made the pact with the University of Colorado, and it was set up with its organizational structure and incorporated in '46 as High Altitude Observatory of Harvard University and the University of Colorado. Then, at the later separation, it just became High Altitude Observatory of the University of Colorado.

DeVorkin:

Right. Can you tell me anything about the Cohens? Are they still in Denver?

Roberts:

No, I think they both died, but Mario Iona worked under them and he now runs it. He was also a great friend of the HAO.

DeVorkin:

So they weren't associated with the Chamberlain Observatory or anything there?

Roberts:

No, that was run by a different person, and I knew him well. But I don't remember his name.

DeVorkin:

Okay. Can you say anything about the work of the cosmic ray group there, because they did do some rocket flights later on.

Roberts:

Well, they did, yes, that's right, and Frank Oppenheimer worked there for a while, too. They ran the Mount Evans Observatory and the Echo Lake Cosmic Ray Station, at the summit and then at the lake halfway up Mt. Evans, and they had groups from the University of Minnesota, the University of Chicago, MIT and so on. Rossi, Fermi, Schein, Bob Williams, all kinds of people came out in the summer and did research there. We also had at Climax during the war, at my observatory, a research group from the University of Chicago under Schein, and that included Malcolm Correi, Robert Williams, Victor Regener, a fellow named Frank Fahy, and the guy who's now head of General Dynamics or whatever it is—Harold Agnew. He was one of the students there.

DeVorkin:

So victor Regener was here during the war?

Roberts:

Oh yes.

DeVorkin:

Do you know when he came here?

Roberts:

Well, it must have been '42 or '41.

DeVorkin:

He must have escaped Germany?

Roberts:

Yes, he did. He escaped Germany and he escaped Italy.

DeVorkin:

Why?

Roberts:

Because of his mother being a Jew and a Russian to boot. Yes.

DeVorkin:

I'll be darned. But how did Erik —

Roberts:

Erik decided to stay, and Victor decided to escape. Victor got through the German border two days before it was closed, and he got through the Italian customs and onto a ship three days before it closed. So Victor came here. Then Victor met his wife in Chicago, Brigit Hamilton, and they were married and spent their honeymoon at our station at Climax.

DeVorkin:

Marvelous. So you had contact with him, as you said, and later on you met Erik Regener.

Roberts:

Right, after the war, at Victor's introduction, I went back and met Erik. That was '48.

DeVorkin:

But you have no recollection of discussing with him any of his wartime interests in using the V-2?

Roberts:

Well, I think I did, as a matter of fact, but I can't remember it.

DeVorkin:

Is there any way that you might be able to reconstruct it?

Roberts:

I was involved with the V-2 stuff here; when did we start firing V-2s?

DeVorkin:

'46.

Roberts:

Yes, so I had been working with Tousey and all those people.

DeVorkin:

Let's talk about what you actually did.

Roberts:

You mean, that summer?

DeVorkin:

Yes, in firing the V-2s.

Roberts:

Oh, I was simply more or less an observer, because I had gotten so close in friendly association with the people who were doing the experiments. I was down there whenever that rocket explosion occurred.

DeVorkin:

Could you talk about that? Because we didn't talk about that on tape.

Roberts:

We didn't talk about that. That was the day we made the American Airlines flight down there to do the site survey of Sac Peak, and I stayed over at the White Sands to observe a flight of a spectrograph of Tousey's, but Tousey wasn't there personally. F. S. Johnson, in Tousey's group, who was also a close friend of mine, throughout that period and now, was there. He became the chairman of the board here. Anyway, I was out at the site, underneath the V-2. They had loaded the fuel, and I was interested to see how the spectrograph was configured in the tail of the thing.

DeVorkin:

This must have been October, '46 or later.

Roberts:

Yes.

DeVorkin:

Could it have been then, or March of '47?

Roberts:

Could have been. I think it was October, '46.

DeVorkin:

That was the famous flight.

Roberts:

No, this flight blew up. Didn't go. Anyway, everything was loaded, ready to go, and they had a piece of primacord — you know what primacord is? It's dynamite in a string. They had wrapped the primacord around the rocket so that at midflight it would bust the rocket in half. That would cause a water chamber and a chlorsulfonic acid chamber to mix and make a huge cloud of smoke, from which we'd be able to study winds.

The acid and water were in adjacent chambers separated by a diaphragm that would break when the primacord went off. It must have been 15 or 20 minutes before launch. In those days they didn't have much in the way of safety precautions. Everybody was out walking around, and we were told that when the alarm went off, we had to go into the block house. Well, I was standing under it, looking at the spectrograph and talking to, I don't even think it was Frank, it was a technician from NRL, from the experiment, whoever was responsible.

DeVorkin:

Purcell?

Roberts:

I don't remember.

DeVorkin:

Was it one of the lithium fluoride bead spectrographs?

Roberts:

I don't remember. But anyway, we had looked at it, how the information telemetering worked and all that. I was very greatly interested in that. Then I noticed or I heard some people speaking loudly up in the middle of the rocket, where they were still doing something or other. They were loading the sulfonic acid. Then I noticed a little wisp of smoke coming out the side of the rocket. The seal between the sulfonic acid and the water was not perfect. And in a matter of seconds, the whole damn thing blew up! The cloud of smoke spread out just like an umbrella to the horizon. Everybody started to run for the blockhouse.

DeVorkin:

Because they thought this could ignite the fuel?

Roberts:

Yes, oxygen began jetting out, because the insulation had been all soaked, and four guys were killed, I think.

DeVorkin:

Four guys were killed?

Roberts:

I think so. I won't swear to that. But I remember doing first aid. I was trained in first aid. I had been a first aid instructor. These poor devils had been sprayed with sulfonic acid, and they were burned all over. They were stripped. It was such a hot time, it was just at sunset, it was a sunset launch.

DeVorkin:

Could this have been one of the meteor experiment rockets that Zwicky was involved in?

Roberts:

All I remember was the spectrograph. It was about an hour before sunset, because the sun was still up. We did first aid, and then, it was over. Some guy donned a fire suit and went out and opened the relief valve and let the oxygen spill out on the desert. We all had to stay in the block house. They rescued the four guys, and they were alive, but I understand they subsequently died. They were burned almost all over. Then after that they instituted all kinds of safety regulations, and you couldn't be out there, in a casual way, the way I was.

DeVorkin:

Was the rocket totally scrapped?

Roberts:

I suspect so, but I don't know.

DeVorkin:

Then you don't know what happened to the spectrograph?

Roberts:

I don't think the spectrograph could have been hurt, because I was standing right under the tail fin, and I didn't even get any acid spattered on me, but two guys as close as you and another one did get acid. They didn't get enough acid to get hurt. It just burned holes in their shirts.

DeVorkin:

How did this make you feel about rocket research?

Roberts:

Well, you know, to this day I get a sensation of almost fainting whenever I hear a door slam. If some unexpected loud explosion occurs, I get this tense reaction and I almost faint. Bad enough. That occurred as a result of this explosion. It scared the very shit out of me. I didn't sleep for two nights.

DeVorkin:

I can imagine. Did you experience any of the other launches?

Roberts:

Yes, I saw quite a few launches.

DeVorkin:

Did you talk while you were there at White Sands with any of the people about spectrographs and the use of V-2s?

Roberts:

Yes. But I don't remember much in the way of details. I remember going down for one of Bill Rensels launches that did not succeed. The rocket didn't launch.

DeVorkin:

He never launched on a V2, to my knowledge.

Roberts:

No, they were Aerobees, weren't they? I don't really think I was so much involved in the details of the rocket instru¬mentation. I was interested in it, and, like that time I was there, I was glad to be shown around by the people who had done it, and I had participated in early planning of different experiments.

DeVorkin:

In these meetings.

Roberts:

Yes, and also with Rense and that group here. I used to get their Weekly Memos of Progress and all that sort of stuff. Then we had seminars every week. The High Altitude Observatory was on the campus, just a hop, skip and a jump from the physics department, and so we had joint seminars, and Bill would be at most of our meetings, and I would go to most of their rocket planning meetings, in the early days. Then later I didn't pay as much attention to that, when I remember being a little appalled when they decided to separate it out of the physics department and set up Ball Brothers.

DeVorkin:

Why so?

Roberts:

Well, I kind of thought it was a great thing to have in the university, and lots of graduate students involved and exciting and all of that. And I was afraid that ...

DeVorkin:

Were you involved at all?

Roberts:

I had nothing to do with it after it went to Ball Brothers, other than that I knew the people. Then of course we hired Ball Brothers to do a lot of our work later.

DeVorkin:

Sure. But do you know what other people at the University of Colorado felt about this separation?

Roberts:

Well, Pietenpol and a fellow named, I think, Hunter—Rense can tell you this — were all gung-ho for it because they felt they wouldn't have to do all the money raising and that Ball Brothers would give them some assets and so on. I think they were all most enthusiastic about it, and there was, now that I recall, some opposition towards having research that seemed to be oriented to military on the campus. I'd forgotten that, but that was another factor. Interestingly enough, HAO and NCAR have never had that problem. Nobody's ever perceived us as being military-related.

DeVorkin:

And you're not.

Roberts:

And we're not, and we're not classified at all. I think there may even have been some classified parts of Bill Rense's work. I'm not sure. But if there were, that would have been a reason to move it off the campus, because there was strong opposition. You remember, the Wisconsin computer got blown up, because the students thought it was connected with military research.

DeVorkin:

But that's the late sixties. We're talking about '56.

Roberts:

Yes, you're right.

Roberts:

I'm thinking about the Vietnam period; that didn't apply then, no. Although there was faculty opposition to any classified research on the campus, way back then.

DeVorkin:

Would you classify Colorado people at the university as quite liberal?

Roberts:

Yes.

DeVorkin:

All through the period?

Roberts:

Yes.

DeVorkin:

Why is that?

Roberts:

It's one of the things that always appealed to me, compared to Harvard. I felt Harvard was not very liberal.

DeVorkin:

Good point. Why Colorado?

Roberts:

It was the tradition of this institution. I don't know exactly why. David Hawkins had been a member of the Communist Party, and he was accused of being a security risk, teaching at the university, and President Stearns, simply by fiat, said that the only qualification was the quality of his teaching and he set up a faculty committee to evaluate the quality of his teaching, and it was no business of the regents. A strong liberal stand. Even though Stearns was a staunch Republican, and very conservative. If he'd been a liberal, he probably couldn't have done it.

DeVorkin:

That's fascinating.

Roberts:

But it was a university with a very liberal tradition. It had, at one time, an active chapter of that student Communist movement, and it had all kinds of left wing clubs, and that's probably what attracted my unknown to me near-namesake Walter R. Roberts to the campus.

DeVorkin:

You mean SNCC, Student Nonviolent Coordinating Committee?

Roberts:

It was called AYD, American Youth for Democracy. It was considered to be a Communist front in the late forties, right after the war.

DeVorkin:

Let's move to something else, back to instrumentation. You wrote a chapter in Kuiper's THE SUN, and in there you discuss sun followers, and that you started beginning to develop sun followers with the coronagraph as early as '46.

Roberts:

Yes, I built what I think was probably the first one, the first servomechanism to control a telescope. I wouldn't be sure about that, but I'd never heard of one. It was suggested by an engineering friend of mine in Connecticut.

DeVorkin:

Who was that?

Roberts:

His name was James R. Balsley. He was the father of my graduate school chum, and he was an electronics engineer, built some of the first inverse feedback amplifiers. He was the sound expert for one of the big Hollywood studios which was subsequently run by a student who was the daughter of the founder Talmadge. Anyway, he was an electronics expert in the thirties, and he suggested making a sun follower to me in the forties, while I was at Climax, and he sent me a hand sketch of how to do it. He designed an amplifier that would operate off of photo cells.

DeVorkin:

Boy, he really did help you out.

Roberts:

Yes, he really did. I used light pipes for it, what is now called fiber optics. It was a prototype of fiber optics, to carry the image from the occulting disk out to this big photo cell. So I just had a bent lucite pipe, which I bent myself, and then, the end of the lucite came directly behind an image of the sun with an eclipsing disk, like the coronagraph, only just a lens and an image. It was the same focal length as the telescope itself so it participated in the same flexures. Then, when the thing got decentered, it sent a signal to the drive, which corrected the position of the telescope, so it was a servo-mechanism.

DeVorkin:

So you had four of those.

Roberts:

Four of those pipes.

DeVorkin:

And you had two pairs of photo-electric tubes behind this occulting disk.

Roberts:

Right.

DeVorkin:

I know in your article you talked about a few of the other designs that were around. Whitford and Kron had been working on one, not so much for the sun but for stars and things like that. But this certainly was in the beginning of automatic following. Did this experience ever flow over to your discussions with Rense or with Pietenpol?

Roberts:

I suspect so, but I don't remember it explicitly, but I know that at that time we developed the roller drive and the full servomechanism, where even the basic time is kept by the servo. We didn't have a clock. I'm sure we discussed all of these designs with the Rense group, but Bill could probably tell you that, whether we had an interconnection of designs. I just know that we worked closely together, and, of course, their problem was very different. They had very large excursions to deal with.

DeVorkin:

Right. That's a fascinating possibility, though. You mentioned a moment ago that there were these weekly reports from the Colorado group.

Roberts:

I think so. Weekly or monthly, I can't remember, but they were periodic summaries of progress.

DeVorkin:

Do you recall saving them or throwing them away?

Roberts:

No, I think I threw them away. I saved the High Altitude Observatory ones, but I think I threw those away. What are those two yellow-red books?

DeVorkin:

These are NCAR, 1960, 1961, research notebooks. Then '71, something called JAWS.

Roberts:

No, that's not it. They're similar to those red books, but they go back to the early days of HAO. They were called solar research memos. Every time anybody had an idea they wrote a solar research memo and put it in the file and everybody saw it. I feel pretty sure that Bill Rense got those.

DeVorkin:

Those are from HAO.

Roberts:

Those are from HAO. They're somewhere. I'll bet you they are in my collection. By the way, there's one thing that's not in my collection; that is, a series of speeches, speech notes, because I kept using them, but I think I have some historical speeches.

DeVorkin:

Yes, certainly, I think there are some historical speeches in your collection that I noted, but I'd be interested to see what you have here. It's a Hollow Square?

Roberts:

These are my notes for a Hollow Square lecture, at Boulder, 16th of April, 1954.

DeVorkin:

As long as we note for now that you've retained these as an historical source. It's good to know, and eventually they will be deposited in your papers?

Roberts:

Yes. They may be already in there.

DeVorkin:

I know that there is a section on Hollow Squares. Announce¬ments and that sort of thing.

Roberts:

Yes. These may not be duplicated anywhere except right here. This may be the only place, because I noticed a lot of them are in handwriting. But I do know that I did a couple of talks about the early history of science in Boulder, to different groups.

DeVorkin:

That would be very interesting.

Roberts:

"Cooperative Scientific Experiment in History, the IGY." That's done in 1958. Oh, here's one — called "Satellites and Moon Rockets, Progress Report." DeVorkin : When was that?

Roberts:

'59.

DeVorkin:

Yes, post-Sputnik.

Roberts:

"Sputnik and the World Missile Race." '58. "Los Alamos Talk." You get an idea of the political orientation, "Sputnik and the World Missile Race," then three or four scientific ones, and then, "The Real Meaning of Earth Satellites" — that was a political one. "What are the Astronomers' Views" — "Science and Revolution."

DeVorkin:

What is the one, "What are the Astronomers Views"?

Roberts:

8th of May, '57. It says, "For our generation, travel with instruments beyond three miles altitude of great importance; space travel for people less inviting; probably not for our genera¬tion." And then, "I don't want to spend 40 years getting to a star where there's one in a million chance of finding somebody friendly." It's just, "To the astronomer, the scientific prospects of interplanetary travel are one of the great challenges of the century."

DeVorkin:

The idea of getting to the other planets to examine them. You said that before Sputnik.

Roberts:

Yes.

DeVorkin:

That was '57, May 8 and October '57 was Sputnik.

Roberts:

Here's one called "Space Travel, a Symposium of the Aeromedical Association, May 8," that's the same day. This is the text. Oh, I wrote this up for publication.

DeVorkin:

It was then published?

Roberts:

I guess so. I don't remember. But I talked about space travel I think a lot before that. "Two weeks ago in Washington I had a talk with Minkowski, and saw a plate on which the average mark was two thousand million light years. Where is the earth in respect to this?" "Multiplicity of places of life, our particular earth as an abode." I don't want to take the time now with this. Here's a reference to Broxon and his work, that I mentioned.

DeVorkin:

Good. Talking about some people now — you've already mentioned R.N. Thomas and the fact that he came here. Grant Athay was also involved.

Roberts:

Grant Athay was a graduate student working with Dick and me at Utah. Dick was at Utah in the physics department, and Grant did his thesis under Dick with help from me, analyzing, if I remember correctly, the results from the '52 eclipse, the plates that were successful. Yes.

DeVorkin:

One of the motives for moving to Boulder was to develop a strong theoretical component — who did you bring in? Was that Thomas?

Roberts:

No, Thomas never was on the staff. He was a summer visitor, and I brought in a lot of visitors, like Arnold Schlueter from Germany, and Herman Schmidt and Eugene Parker. Gene Parker actually accepted a position here, on the staff, but then got an offer from Chandrasekhar and went there instead. Right after his doctorate. To the permanent staff, I brought Donald Billings, who had been teaching I think for one year at the University of Colorado; I met him on a sabbatical. He was at Louisiana State, and he was one of the first scientists that I brought on a permanent basis. Then Gordon Newkirk was one of the early ones. I think as soon as he finished his doctorate he came here. Jim and Constance Warwick, Harold Zirin.

DeVorkin:

Harold Zirin came here?

Roberts:

Yes, he came here, and Jack Zirker did his Ph.D. here, I think, on the eclipse stuff, supervised again I think by Thomas and by somebody else.

DeVorkin:

So you had a lot of contact with Thomas. He spent the summers.

Roberts:

Oh yes. We also set up a thing called the Solar Associates.

DeVorkin:

That's what I wanted to ask you about. What is that?

Roberts:

Well, it was an informal meeting among all the people interested in solar physics, including Fred Whipple at Harvard, Thomas, myself, and Jack Evans. It was like a small club that met for a week every year, to go over everything that they were doing, and all of their plans, in an informal atmosphere, so that they could coordinate their research. We included, if I remember, Orren Mohler from the McMath Hulbert Observatory, and then as soon as they finished their doctorates and stuff, people like Bill Livingston at Mt. Wilson and the Kitt Peak people.

DeVorkin:

Much later on.

Roberts:

Much later on, the people who went to Sac Peak later. The first meeting was held here. And then I think the second two meetings, annual meetings, usually in May, were held at Los Alamos. There was a guy named Foster Evans down there, a great mathematician, and he was our host.

DeVorkin:

Were you involved with people who were doing solar models at that time?

Roberts:

Schwarzschild, you mean?

DeVorkin:

No, the guys at Los Alamos — Cox ...

Roberts:

I don't think they were there yet – Cox — as soon as Art was there, he was involved.

DeVorkin:

Well, the kinds of theoreticians you were looking for, what kind were they?

Roberts:

Well, we weren't looking only for theoreticians. This was everybody engaged in solar physics. It was a very small community.

DeVorkin:

For Solar Associates, right. But for staff members here.

Roberts:

Oh, for staff members here. Well, we were largely experimental, so our first big success at observation, other than the coronagraph and all that, was the '52 eclipse in Khartoum. I also brought Jean Claude Pecker from France, and his wife, Charlotte, she was also an astronomer, and Gerard Wlerick and Andre Lallemand. He was here for a short time.

DeVorkin:

Was that to work on image tubes?

Roberts:

Yes, and also optical devices. We brought Yngve Ohman here for one year from Stockholm. He was probably the inventor of the birefringent filter. I'm not sure, but he and Jack worked for a year together on new birefringent filters and other optical components using half-wave plates and polarization and all that.

DeVorkin:

So you weren't looking to build up a large theoretical component.

Roberts:

No. Zirin was a theoretician, Thomas, the Warwicks, and Billingswere theoreticians. We read Alfren's COSMICAL ELECTRODYNAMICS together, Billings teaching us, just the group. We met once a week or twice a week to study that book, and that was the beginning of plasma physics in astronomy.

DeVorkin:

You call it experimental astronomy. That's an interesting term. Pecker used that term in a Lydell book somewhere, but would most astronomers call it experimental or would they call it observational astronomy?

Roberts:

All right, call it observational.

DeVorkin:

What are your reasons for calling it experimental?

Roberts:

Well, I consider myself an experimentalist because I build things. I would have to admit, there's a valid distinction. You don't operate on the sun, you know, manipulate it. You just observe it. But I wouldn't make any distinction between the terms.

DeVorkin:

Okay. In bringing in students to work at HAO, for example, in the case with R. N. Thomas and Grant Athay, you brought in students of other astronomers, solar physicists at other institutions who could come here and do their work, is that right?

Roberts:

Well, when I went to Harvard in '47-48, fall of '47, spring of '48, I taught an undergraduate course in astronomy and a graduate course in solar physics, and out of that came an incredible number of Ph.D.s in solar physics. Dick Thomas was one of my students, Gordon Newkirk was one of my students there — John Wolbach, Barbara Bell, Connie and Jim Warwick.

DeVorkin:

I see. Really a lot of students. These all had been Menzel's students of some sort?

Roberts:

Yes, they'd all been at Harvard, one way or another, and I'd taught that course in solar physics. Then, when I came here, immediately the next year I taught the same course and had a whole bunch of students from the University of Colorado, including a young man named Fred Dolder who later became an important person in Ball Brothers.

DeVorkin:

Right. Dave Stacey by any chance?

Roberts:

I don't think Stacey took my course, but I did work with him. A fellow named Ray Grenchek was from Princeton. We had a summer program to which we brought students from everywhere. Martha Liller came. In fact I think she met Bill (Liller) here. Schwarzschild was here a couple of times.

DeVorkin:

Schwarzschild was very interested in the problem of surface convection.

Roberts:

He was interested in the heating of the corona. He visited the Climax Observatory in the summer of '40 and many times thereafter.

DeVorkin:

Do you recall what his interests were at that time? Was it that at the time?

Roberts:

I can't really recall, but I think so. He wanted to climb the mountain. But we were friends from Harvard. Also Teller and Bethe visited in '40 and '41 in the summer, when they were together on their vacations. They used to go on vacations together, driving an old Ford.

DeVorkin:

That's nice. In the case of Schwarzschild, that would be very interesting to determine. I know that he did the stratoscope to look at convection.

Roberts:

Right. And Grenchek was his student. He came here for a summer. We had a real active place in the summer. We had about twice as many people in the summer as we did in the winter. We brought Sydney Chapman also, one of the senior theoreticians.

DeVorkin:

Also one of the founders of modern geophysics.

Roberts:

Right.

DeVorkin:

The summer programs, they've extended for years, I take it"

Roberts:

Yes. They still go on.

DeVorkin:

But there was another interesting interval, during the Korean War or just in general during the fifties. Newkirk told me that he was able to get himself detailed, when he was in the Army, by the Signal Corps, to Sac Peak, to HAO.

Roberts:

To HAO first. He worked on the summit of Norway Mountain in the Arapaho Basin ski area, rode up on the chairlift.

DeVorkin:

He was doing the sky photometry work.

Roberts:

Right, with that prototype coronagraph that Jack had developed.

DeVorkin:

Now, how common was this?

Roberts:

He worked for the Army Signal Corps, and he worked for a very brilliant scientist there, and he was very persistent. He was a private — but did he have his doctorate yet?

DeVorkin:

I'm not sure. I think he was a post-doc.

Roberts:

This was his first post-doc year, and he talked them into realizing some kind of interest in sky photometry, I don't know what. But the guy that he worked for at the Signal Corps was a very brilliant atmospheric scientist in atmospheric opacity and things of that sort. I can't remember his name now.

DeVorkin:

I probably got it from talking to Newkirk. I talked to him a few months ago.

Roberts:

No, that wasn't a common arrangement. The only arrangements like that were Lewis Larmore, a Navy lieutenant during the war, and Gordon.

DeVorkin:

Okay. This might be a good place to stop, then.