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Oral History Transcript — Dr. Walter Roberts

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Interview with Dr. Walter Roberts
By David DeVorkin
At Dr. Robert's Office, NCAR, Boulder, Colorado
July 26, 1983

open tab View abstract

Walter Roberts; July 26, 1983

ABSTRACT: This interview reviews in detail Roberts' childhood experiences before addressing his work on the solar corona; solar spicules and prominences; the orgins of geomagnetic disturbances; and the influence of variable solar activity on the earth's ionosphere and weather. Roberts also discusses his graduate education under Donald Menzel at Harvard, his varied career as a researcher and administrator, and his participation in the establishment of the Climax, Colorado solar coronagraph station of Harvard College. Other topics and affliliations discussed include: his work as Director of the High Altitude Observatory (1946-1961); his tenure as Director of the National Center for Atmospheric Research (1960-1968); communist investigations among scientists; the observatory at Sacramento Peak; rocketry research; and his relationship with Harlow Shapley.

Transcript

Session I | Session II | Session III

DeVorkin:

Dr. Roberts, I know that you were born in 1915 in West Bridgewater, Massachusetts, but I would like to ask you a little more about your early home life, who your father and mother were, and your education.

Roberts:

Fine. My dad was from Ohio. He was a football coach and a star athlete, and in the early days a semi-pro baseball player. They just passed the hat around after the ball game and collected some money from the audience and then split it up among the players. The winning team got two thirds and the losing team got one third. I used to go to a lot of those ball games. My dad was also a farmer. My mother was from upstate New York, a place called Orr's Mills. Her name was Orr. It was near Cornwall and West Point. My father and mother moved to Bridgewater, Massachusetts about four years before I was born, because my dad graduated from college in 1911.

DeVorkin:

What college did he go to?

Roberts:

He went to Amherst. He actually had gone to Swarthmore, but they had a football scandal at Swarthmore, if you can believe it. He was barred from playing football at Swarthmore because he had a scholarship job that was not a real job but just put the money in his pocket. He transferred to Amherst after that football scandal.

DeVorkin:

Was your family Quaker in origin?

Roberts:

My father's family was Quaker in origin, but not my mother's. My dad then transferred into track and became a really outstanding track athlete, and then as a senior at Amherst he was eligible again to play football. He had gotten onto the U. S. Olympic team in three events — the 100 yard dash, the broad jump and high jump. He had tied the world's record in the 100 yard dash. But he broke his leg in what would have been his last football game, so he never went to the Olympics in Stockholm. It broke his heart. He then took one year of study at the University of Massachusetts, which is just across town from Amherst College, and was then called Massachusetts Agricultural College.

He studied orcharding, and the growing of corn for human consumption, not field corn. He bought a small farm in West Bridgewater and started farming about 1912, three years before I was born. He also got a job as football coach and teacher at Brockton High School, which was the main school of the nearby city. He and my mother then built a house on the farmland that they had bought. My dad began what was a lifetime career of farming in the summer and coaching football in the fall.

DeVorkin:

What was your father's full name?

Roberts:

My father's name was Ernest Marion Roberts. He was an extraordinarily good football coach. He had all kinds of offers to go into big time, but he preferred to stay in a high school and run a farm, and he did that until his retirement and until my mother's death.

DeVorkin:

When was that?

Roberts:

I don't remember the year of my mother's death but it must have been about 1949. My mother had come from a family of millers. They had a dam on a little creek called the Moodna. They made a little lake and they had a water-powered mill and ground grain for the local region, and became very, very prosperous. My mother's father died when he was relatively young, and when I was about one year old, and my grandmother, my mother's mother, moved to New York City shortly thereafter, having substantial means, and became quite a patron of music and the arts, and set up a philanthropic society for older people called the Relief Society for the Aged. T

hey erected a bench in Central Park in her honor a few years later. All of that's gone now. But I remember as a child, I used to go down and spend a few weeks or a month in my grandmother's penthouse on the top of the Hotel New Yorker near Pennsylvania Station in Manhattan every year. I developed a lifetime distaste for opera because I had to go to the Metropolitan Opera every week I was there and I hated it. Strangely enough, I loved symphonic and chamber music.

DeVorkin:

What was your mother's full name?

Roberts:

My mother's name was Alice Elliot Orr. My grandmother was Angelique Veith Orr. We have complete family trees for both sides of the family, going back about six generations. I was going to say that my father's family originated in Ohio and Pennsylvania, and they were Quaker mostly. My mother's family were Scotch and German and French, and my grandmother spoke three languages — French, German and English. Very interesting woman. My mother was also very dynamic, took after her mother, and she was involved in all kinds of civic activities while — was at home. She was educational director for our church, and she was chairwoman of the YWCA and all that sort of stuff in town. My dad of course was very active in civic affairs also. In addition to his coaching and his other duties, he was prominent in the city. We lived in the country just outside the city and had a very good business growing asparagus in the spring, sweet corn in the summer, and apples in the fall.

DeVorkin:

Did you help out on the farm?

Roberts:

I hated farm work. My mother says that when we were hoeing corn, I would sneak off from the end of the corn row, when we got near the edge of the corn field, sneak over the hill and go look for wildflowers and blueberries or something like that. I didn't like getting up early in the morning to pick the corn and all of that sort of stuff.

DeVorkin:

How many brothers and sisters do you have?

Roberts:

I had one brother and one sister. My brother was about a year younger than I, and my sister about six years younger. My brother was a dive bomber pilot and was killed in action in World War II, and my sister now lives in Washington and I see her frequently. My mother and father used to send me down to an island off New Bedford called Cuttyhunk Island in the summers. It's actually the oldest settlement (Gosnold) in New England. I stayed with a secretary from the Brockton High School who was a friend of the family — a wonderful maiden lady!

It was to get me away from the pressure of the farm work, because I really wasn't very strong. I stayed there for a month or so, and I loved it, canoeing with Miss Brewer, the secretary, and hiking on that beautiful island, and just taking it easy. I lived in the home of a sword fisherman, Frank Veeder, who ran a little boarding house with about six or eight rooms, and the high school secretary, Miss Brewer, sort of took care of me. I did that for many years as a youth.

DeVorkin:

Was there any disappointment from your father's side that you weren't able to take part in the farming?

Roberts:

I think so, although he was pretty tolerant. He was a very hard-driving man, and he didn't want anyone around who wasn't doing what they should, but at the same time he was sensitive enough to make an excuse by letting me go off in the middle of the harvest work at the farm. I developed a strong interest in science. We had a man friend of the family who was an engineer, and he had a major influence on me. He had a private machine shop, and he helped me to build a home telescope. I made a six inch reflector telescope when I was in high school or junior high, and I also developed a great interest in photography.

DeVorkin:

When was this and what was this man's name?

Roberts:

His name was Lincoln K. Davis, and he was a very wealthy man. His father ran a big business in somewhere like Florida or Texas, I think; he didn't work for a living, he just puttered around in his machine shop and stuff. I used to go every day after school. He was a magnificent man. My school got out early, and my father would drive home from football practice late, so I had two or three hours after school. It was far enough so I couldn't go home, so I used to go to Linc Davis' house and work and play at his machine shop, and that's how I got interested in building things. I developed a great talent as a model builder. I won the New England Championship for model airplanes and things of that sort.

DeVorkin:

Did you belong to any clubs?

Roberts:

Yes.

DeVorkin:

How far were you from Boston?

Roberts:

It's about 20 or 30 miles from Boston. But we didn't have much interaction with Boston. We used to go occasionally to Boston to see the baseball games.

DeVorkin:

They had a big amateur telescope making club there.

Roberts:

Yes, and I went to Stellafane where they had that amateur telescope thing up in Vermont, and I was very active in that group. But there was a Brockton chapter and Lincoln Davis was one of the founders. He used to drive me up to the meetings in the summer at Stellafane.

DeVorkin:

Did you meet Albert Ingalls?

Roberts:

Yes, I did.

DeVorkin:

Russell W. Porter?

Roberts:

I'm not sure about Porter. I think so but I'm not absolutely sure.

DeVorkin:

When you made your first telescope, were you more interested in making it or using it?

Roberts:

Both. I was equally interested in making it and using it.

DeVorkin:

What did you use it for?

Roberts:

Well, around the house I've still got the old star charts, where I first identified globular clusters and spiral nebulae and all the things that you would look at — cor caroli as a double and all of that. I used to go out night after night after night, and hunt for new doubles and all sorts of things like that.

DeVorkin:

Did you join the AAVSO?

Roberts:

No, I didn't. I don't know why. Later I knew all those people when I was in graduate school. I also had a very very great interest in aviation, and I built scale models of operating aircraft like the old Pan Am Clippers, the earliest ones, and I also made free flying models for endurance and altitude. They were all rubber band powered, in those days.

DeVorkin:

You didn't have the little one or two cylinder engines?

Roberts:

No, we didn't have them. We made a lot of gliders that you could just launch by throwing, and had contests with them, and we also made a real glider that you could fly in, that you could ride in. It flew about four times and crashed down on Cape Cod.

DeVorkin:

"We" being who?

Roberts:

A group of about five friends — this was junior high school and high school. One of my friends became the chief pilot of KLM later, and another one was president of the Aero Club and he went to MIT in aeronautical engineering. That's what I wanted to do, but my family wouldn't hear of it. They wanted me to get a classical education at Amherst, and so I was gravely disappointed when I finally had to go to Amherst instead of MIT.

DeVorkin:

So Amherst was more of a family tradition?

Roberts:

Right.

DeVorkin:

Was that more from your father's side or your mother's side? Roberts -6-

Roberts:

It was from my uncle's side, Walter Orr, the man for whom I was named. He was a New York lawyer and he was a trustee cf Amherst College. He was a friend of my father's and had introduced my father to my mother. He was a very wealthy man. My family was, particularly in the Depression, kind of poor. Although we were never really poor — we always had a couple of servants in the home and working on the farm — we considered ourselves to have to be careful with money, and going to college was a big expense. So my uncle paid a good deal of my college expenses, although I did work through college, washing dishes in my fraternity (DU) restaurant and serving as business manager of the fraternity, and a photographer for campus events. I was in pretty good health by the time I went to college and had gone out for track and was on the cross-country team, but I never was any great athlete.

DeVorkin:

Before we get to Amherst, was there anything from your grade school and high school education that you feel is important to understand your career? Did you go to public or private school?

Roberts:

I went to public school, and the Brockton schools were extraordinary in those days. I studied four years of Latin, three years of French and two years of Greek in a public high school. I had a mathematics training of at least five years in high school. I had an extraordinary geometry teacher, Miss Geraldine Farrar. I had a biology teacher named Stephen Cote. He had a biology club and Miss Farrar had a geometry club. The school also had a French club under Mary Louise Reilly — an incredibly forceful and dynamic teacher, and school activities were very very strong and very academically oriented. Brockton prided itself on its schools, even though the town was really in very bad economic shape in the Depression.

There was a very large Italian community and a very large Swedish community and a large community of what we used to call Jugos — I now know that they were Yugoslavs. It wasn't a term of contempt, but it was what we called them. My family was fairly prominent in social circles, but my own personal friends were mostly from the Jugos and the Italians. My mother was always unhappy that I didn't associate so much with the friends she liked, and I always liked my friends better than their friends.

DeVorkin:

Did you find among them people who were interested in flying and astronomy?

Roberts:

Not so much. There were gangs. I got my nose broken in a fist fight and things like that. I studied violin and they used to kid me about that. I played the violin for 25 years, and the piano for 10 or 12, although I was never terribly good. But my mother insisted that I go to ballroom dancing school, and that was one of the things I hated most in life. I used to have to go home on the Trolley car after the dancing school, and I developed a fear of a particular very large tomboy black girl, and her name was Roberts. She used to lie in wait for me and beat me up and take my pennies and my candies! I'd often walk home four or five miles rather than ride the trolley car.

DeVorkin:

She'd be on the trolley?

Roberts:

She'd be on the trolley waiting to see when I got on the car.

DeVorkin:

Why did she have it in for you?

Roberts:

She always knew I had a little money. Only a dime or a nickel or something. She had it in for me, and I was deathly scared of her. She was huge and I was small. But I hated going to dancing school, and I developed a major fear of dancing which I didn't overcome till I got married. My wife was a wonderful dancer and she taught me to ballroom dance and to square dance in groups here in Colorado when we moved immediately after we were married.

DeVorkin:

So that was just the zeal of your mother towards making you a social person, rather than having you learn dance as an art form.

Roberts:

Right, absolutely. It was not an art form, it was social grace. They belonged to the country club and used to want me to go to the country club dances.

DeVorkin:

And how did you feel about that?

Roberts:

Terrible. I'd go and stay outside, never go inside, but just listen to the music and noise and wish I had the courage to go inside. DeVorkin : Well, you had these three teachers. You had clubs.

Roberts:

The teachers were superb, absolutely magnificent.

DeVorkin:

Was there any physics or astronomy?

Roberts:

Yes. There was an astronomy club of telescope makers that Linc Davis participated in. He used to take the whole club to his shop, and used to help them get hold of all the materials to make telescopes, and used to help them test them and teach them and all that sort of thing. And there was a model aviation club, run by a manual training teacher. They had a nice machine shop in the school.

DeVorkin:

Did you use it?

Roberts:

Yes. But I mainly used Linc Davis' shop. Another major influence was the photography club. I had bought a quite expensive camera after saving up all my money for a whole summer, in about 1930 or '31. I met a man named Woodward who ran a photographic store and did his own film processing, and he used to let me come after school. This was now when I was in high school. I was in a different part of town from where Linc Davis was, so I couldn't go to his place any more. I used to go down to this photographic store, right in the heart of Brockton, and he used to let me work in the dark room, and gave me all kinds of outdated film. He helped me buy the camera — in fact, he bought the camera and held it when I didn't have enough money to pay for it yet.

DeVorkin:

What kind of camera was it?

Roberts:

It was a Zeiss Ikon, with an extension bellows, really a very very fine camera.

DeVorkin:

Was the Zeiss Ikon with extension bellows used for nature photography, close-ups?

Roberts:

I used it for everything, for close-up nature photography, and I used it for portraits. I set up a little tiny business. It didn't amount to anything, but I took home portraits for pay, and gathered quite a bit of spending money that way.

DeVorkin:

Did you ever use it for astronomical pictures?

Roberts:

Yes, but not much. Films were very slow in those days and it was hard to get a good picture, but I photographed the moon and things like that. I did a lot of landscape photography with my telescope of distant things. I remember in my naivete trying to develop a gadget that would turn an out-of-focus picture into a sharp one!

DeVorkin:

Oh, really? This was an optical device?

Roberts:

Yes. Of course it was a crazy idea. I thought I could re-form the rays, but of course, there isn't any image on the film.

DeVorkin:

Let's move on to Amherst, then. You went there in 1934.

Roberts:

Yes. Also in 1932 I went to Europe. I went with a group of boys from junior high and high school. The trip was called "My Friend Abroad," and it was run by a man named Sven Knudsen in Boston. He'd get about 30 boys, and their families would pay a certain sum of money and they'd go abroad and live in a private home. I lived in a private home in Wassenar, which is near The Hague in Holland, for a month, and then did some touring, went up the Rhine River and into Switzerland and back to Paris and then home. We went on an ocean liner, the Veerdam, that took 10 days to cross the ocean.

It was great fun and a marvelous experience, and till this day we ve maintained close family relationships with that Dutch family, now in the third generation. In each case there was a boy of the same approximate age in the home abroad. I stayed with a family named Bruins, who had a son named Jan. Annie Vanderhoff Bruins was the mother of Jan and her husband was an official in the League of Nations and later in the United Nations after the war when the United Nations was created. They were a very cultured, very intelligent, very stimulating family, and we have maintained ties right up until today. Jan Bruins, the grandson of Annie, has come to our house about once a year recently.

I just visited the original Jan's brother. Jan was killed in a motorcycle accident in the 1930's, and I visited his brother in Deventer in 1982. He lived in South Africa most of his life, but every three or five years, they'd come to the U. S. and once or twice visited us in Colorado. A few times I also visited them in Holland after the war, when I traveled all the time. And that was a very important influence on my life. My correspondence with and association with that family.

DeVorkin:

Influence in what way, culturally?

Roberts:

Well, just to give me an international perspective and realization that people spoke different languages. I'd had good language training in school, so I could speak a little French and German. It widened my horizons, I think, quite a bit. Dr. Knudsen, for example, was very aware of what was happening in Europe, and every day of the 10 day ocean trip, he'd give a lecture for about one or two hours about the history of Europe. He warned us of the rise of Hitler — I heard Hitler give a speech in 1932 in Berlin — and he told us the significance of it, and how this might lead to another war.

This was all back in '32. Of course, he was a Dane, and had lived through World War I and had very vivid memories and impressions. So that enlarged my viewpoint of the world very greatly. Now, I was the only child of the three that ever traveled abroad, and again that was partly to get me away from the farm in the summer. I was still quite a frail child, and I can remember, all throughout my youth at least once a week I used to have a migraine that was so bad that I couldn't stay in school. I had to go and lie down some place and I'd get sick to my stomach. It was awful.

DeVorkin:

Those headaches left you later on?

Roberts:

Not until about twelve years ago. I had them all through my professional career. They never happened on a day when I had some important appointments. They always happened on an off day or an off time, and my secretary used to know right where to put me on the floor with a pillow under my head, when I'd get a migraine.

DeVorkin:

These are the ones where you see lights and feel nauseous?

Roberts:

Yes, and occasionally pass out and have a convulsion during the time you're out. It wasn't very pleasant. But later, at the insistence of a doctor friend at the University of Colorado Medical School, I took biofeedback training, and that's when they all stopped. I don't know if it was coincidence or cause and effect. But that was only about 12 years ago. Anyway, I then went off to Amherst.

DeVorkin:

So there was no question; you were going to Amherst. That was tradition in your family.

Roberts:

Yes. And it was also my uncle's money. My family didn't think they could afford to send me to MIT. Besides they didn't think it was the right thing to do. They always said, "Well, you can go to MIT for graduate school." I hated it at Amherst at first. I absolutely despised it. I was pledged to a fraternity, Delta Upsilon, which was also a family tradition. The social fraternities were an outrage at Amherst in those days. I was not a party type, as you can imagine, because I was afraid to dance. But they had parties every solitary weekend, heavy drinking parties. Later I became treasurer of the fraternity and I used to buy the liquor for the weekend, and in the thirties we would think nothing of collecting 600 bucks for one weekend binge, and everybody in the place would be drunk, except a few. I was called "the Christer" in the fraternity house because I didn't drink! I refused to live in the fraternity house. I lived in a boarding house off campus.

DeVorkin:

It was still family pressure that had you in the fraternity.

Roberts:

Yes. And I led a revolt in the fraternity because they refused to pledge any Jews, and one of my friends the first year was a Jew, James Moses. I was always an organizer. I forgot to mention this, but I was vice-president of my class in high school and I was into everything, had a lot of organizational skills, and the same was true at Amherst. So I got the freshman delegation to pledge to a man to resign from the fraternity if they didn't pledge Jim Moses, a Jew, and they'd never pledged a Jew. So they pledged him, and then beat the shit out of him.

DeVorkin:

Oh no!

Roberts:

Yes. And he had a nervous breakdown, had to quit college.

DeVorkin:

I've heard things were bad at that time.

Roberts:

They were awful.

DeVorkin:

Did you take physics there?

Roberts:

Yes. Amherst provided an absolutely excellent education, with a fine faculty, and I really got close to a lot of the faculty people. The physics professor was marvelous, and there was a mathematics professor who became my most beloved professor, and I learned algebra, advanced algebra, matrix algebra, astronomy.

DeVorkin:

Who was that?

Roberts:

His name was Atherton Sprague, and he only died about five or six years ago. I also had outstanding chemistry and physics teachers. Theodore Soller was my physics teacher. He's still living and he was wonderful.

DeVorkin:

I don't know if he was there at that time, but did you have John Hall? I think John Hall was earlier a student there, and later I knew well his astronomical work.

Roberts:

No, John wasn't there yet, but I had his predecessor named Warren K. Green.

DeVorkin:

Did he have any influence on you?

Roberts:

Oh yes. I became an assistant at the observatory. I took all the astronomy courses they had.

DeVorkin:

So you used the 18 inch Amherst telescope?

Roberts:

Yes. And as I say, I took every course I could and I took research projects in physics, in math.

DeVorkin:

Could you describe some of the research projects in astronomy, physics and math?

Roberts:

Yes. In physics, for example, I did a study of whether there was any relationship between the index of refraction of glass and its brittleness. A silly problem but I did it, and I devised a gadget to drop a ball bearing from a variable height until I'd get it just to the height where it would cause fracturing in the surface of the glass. Then I would measure the index of refraction of the glass and try to find a relationship. There wasn't any. Then I had a mathematics project. I can't really remember much about it except that it was in matrix algebra, and I loved matrix algebra. I found it extremely difficult. My professor was himself particularly interested in algebra, and algebra was not a very popular field in physics.

Werner Heisenberg had written the principal quantum mechanics book, but it was from the differential equation formulation, using wave form procedures; but Dirac wrote a book in the matrix formulation. Heisenberg and Dirac covered the same material from two very different mathematical viewpoints, and I could understand the Dirac but not the Heisenberg, so I developed my first knowledge of quantum theory from Dirac and from the algebraic formulation. Unfortunately it was about 15 years too soon to catch up with the computer revolution.

Everything in computers is in matrix formulation. I just wish that my micros had been available when I was in college. I now have four micro computers. I did my first published scientific paper on an IBM "Hollerith machine," using IBM punch cards. I'm getting ahead of the story, because that was in graduate school.

DeVorkin:

That was by the time you were at Harvard.

Roberts:

Harvard, yes. But I studied algebra, minored in math and majored in physics at Amherst. They didn't have a major in astronomy but I took the equivalent of a major in astronomy, and I also took the equivalent of a major in chemistry.

DeVorkin:

Would you have majored in astronomy if you'd had the chance?

Roberts:

No, I don't think so, because remember, it was the Depression, it was '34 to '38, and there were just no jobs in astronomy. I had decided by then not to go into aviation, aeronautical engineering, but to go into physical chemistry and get a job at Eastman Kodak, and I made up my mind to become the president of Kodak.

DeVorkin:

Become the president?

Roberts:

Yes, I made up my mind to become the president, and I figured that the president, 25 years hence when I would be eligible, would have to have a Ph.D. in science. That actually turned out to be the case. The president, when I would have been old enough to be the president, turned out to have a Ph.D. in chemistry.

DeVorkin:

In the summers of '38 and '39 you worked at Kodak.

Roberts:

That's right.

DeVorkin:

How did you get that position?

Roberts:

Even as a sophomore in college, I used to go to those recruiting meetings, when the companies send a recruiter to the campus in May, and they line people up for summer jobs. So in my sophomore year I met the Kodak recruiter. I forget his name now. I tried to get a job as a sophomore at Kodak. Then I tried to get a job as a junior at Kodak.

They were only for seniors, but he became so interested in me that by the time I was a senior, I got a job at Kodak. I had this tremendous interest in photography, and I had read all about C.E. Kenneth Mees, who was director of research at Kodak, and after I was at Kodak I met Bill Swann, who was, I think, son of the famous British physicist. And I worked for Fred M. Bishop, in the Development Department, which was a division of Dr. Mees' Research Lab.

DeVorkin:

Had you been reading the journal THE TELESCOPE by that time? Mees had a number of articles in it.

Roberts:

Yes, I think so.

DeVorkin:

Do you recall the one, "Photography Looks to the Red"?

Roberts:

Yes, I do. I read everything I could on astronomical photography, and I was interested in the photographic process. I tried to make some films of my own. I forgot to mention that this guy who had the photographic store also had the capability of doing color prints, and I learned to make washoff relief prints, dye transfer color prints.

DeVorkin:

They were also called "wash off relief"?

Roberts:

They were then called "wash off." What you did was to make a gelatin that you exposed to light, and it became less soluble where it was exposed to light, and then you washed it with your hand, leaving a layer of gelatin.

DeVorkin:

So you had quite a bit of experience working with emulsions.

Roberts:

Yes. I forgot to say that I had two jobs in college. One was washing dishes in a restaurant, and the other one was doing photography for the photographic department. I met a guy named George Howard, known as Skippy. Skip was the official college photographer as a student. He was two years ahead of me. His mother was national president of the Daughters of the American Revolution! Skippy was a character. He didn't belong at Amherst. I forgot to point out also the fact that two of my college chums committed suicide, while I was in college. One of them for reasons very similar to the way my Jewish friend got beaten up. He couldn't get into a fraternity, even though he'd come from a very nice family in Brockton. He didn't have all the proper social graces and he didn't play football and so on. He didn't get pledged to a fraternity, and he committed suicide.

DeVorkin:

It sounds like a rather vicious place, if you're not well placed.

Roberts:

Oh god! My senior year I led a movement to get all fraternities withdrawn from national fraternities at Amherst, and go into social clubs. I agitated with Phi Psi to pledge a Negro, and they did and got thrown out of their national, and I nearly got thrown out of my national. By that time, I was treasurer and business manager of the fraternity, and in everything except name I was running the fraternity. So I started a movement, and I gave the commencement address my senior year on "Down With Fraternities!"

DeVorkin:

Were you ever physically abused for this activity?

Roberts:

No, I was never physically abused. You mean in the fraternity?

DeVorkin:

Yes.

Roberts:

Well, we had the normal hazing, which was pretty rough, but I was never hurt physically. I had become very adept at avoiding any kind of physical conflict. I was very knowledgeable about the wilderness. As a child I used to go with the hired man on the farm, Freddie Bisbee, into a place called the Hockomok Swamp. It was a huge, almost seemingly endless swamp, with lagoons and we used to go at night and fish for eels and turtles. It was full of mosquitoes. I got a sense of being on my own in the outdoors. I went to Maine, in the woods, and I used to sail for two or three days in the Elizabeth Islands in a catboat, with another friend. So I loved the out of doors, and at Amherst the out of doors was also very very beautiful.

But most of the guys there were city guys, and when the fraternity would take you out and dump you in the woods, as a hazing thing, I was the one who always knew how to get back. I knew the terrain, so they couldn't get me lost. There were good things about Amherst. The fraternities were not all bad. I developed a lot of real friendships within the fraternity. The guy who became my life long friend, John Atherton, was a fraternity mate of mine, and we lived together off campus. We had a DKE, Delta Kappa Epsilon, guy who didn't want to live in the fraternity either, and the three of us roomed together for three years off campus. I got to know Robert Frost, who lived across the street.

We used to go to his home every two weeks or so, and listen to him read poetry. David Morton, the poet, was there. The music appreciation stuff was wonderful, and the history professor was marvelous. We used to go to his home. Then there was an English professor named Newton McKeon who was an inspiration to me. So I have very good memories of Amherst as well as the bad ones. But sometimes the bad ones seem to dominate in your memory-.but the good ones were very good. And by the spring of my freshman year, I had gotten so I could adjust to it.

DeVorkin:

So about the Kodak summers, what did you do?

Roberts:

I was in the development department under a man named Fred M. Bishop. The development department was one of two parts of the research lab under Kenneth Mees. There was the pure research, and there was the development side. But I did, interestingly enough, have a lot of contact with Mees, who knew of my astronomical interests and so on, and a lot of close personal contact with Fred Bishop, who was a marvelous man. I was in a group that was really incredibly close and friendly. We were developing new products. We had to do two things.

We had to develop new products for the company, and test them out, and we had to test the competition, so that Kodak knew what the other companies were doing. Occasionally we had to do very unusual things; for example, my boss in my first year at Kodak, had to re-design the optical system of the Bell and Howell projector, because it wouldn't project Kodachrome very well. It was such an inefficient optical system that the Kodachrome didn't show up well on the screen and Kodak was losing money, because people who had Bell and Howell projectors didn't like their pictures. So we redesigned the optical system, and gave the new design to Bell and Howell, and they went ahead and marketed it, and they still use that same condenser svstem that Kodak designed back then.

DeVorkin:

Was the sprocketing different?

Roberts:

No, the sprocketing was the same. I think the light taken through the gate, from the bulb to the gate, was inefficiently used, and they were getting only about 40% as much light as they could from the bulb through the film. It was just a matter of poor optical design, and Kodak had superb optical experts. So we redesigned the optical system for Bell and Howell, in order to sell more Kodachrome. At least that is how I remember it. Then a crazy guy came around with a camera that you could take pictures and develop them immediately, and we tested that camera and decided it was impractical. His name was Edwin Land!

DeVorkin:

You met him then?

Roberts:

I think so. I'm almost sure of it. We became friends later, and we've tried to recall whether we met then or afterwards. Land was a close friend of my professor at Harvard, Donald Menzel.

DeVorkin:

Let me ask what contact you had at that time with the development of spectroscopic emulsions. Any at all?

Roberts:

Almost none. I was mainly in consumer products, Kodachrome. However, I stayed in the home of a woman and her husband, John Norris. The woman had been my mother's best friend in Brockton. She had been in the church with my mother and had been something under my mother, and then she married and they lived in Rochester. Her husband was the young new physician in the medical department at Kodak. They had a house out on the lake, and I stayed in their home while I worked at Kodak, and went to work with him in the morning in his car.

The next door neighbor was a man named Capstaff, who helped develop Kodachrome. There were two inventors of Kodachrome who were New York musicians, if I remember correctly. They invented it, but Capstaff made it work. Capstaff was head of the development of Kodachrome at Kodak. I fell in love with his daughter and became engaged to her, that first year that I was at Kodak. That was after my senior year in college. I had more or less formulated my game plan to stay at Kodak, and so when I went to graduate school, I had a fellowship from Amherst, and I also had a fellowship from Kodak. It was rather small.

DeVorkin:

These were your sources of funds to go to Harvard?

Roberts:

Yes. Kodak had an incredibly far-seeing liberal program of education. They would support you almost indefinitely, as long as you made good progress. So I enrolled in physical chemistry at Harvard under Prof. Otto Oldenberg, and started out. He was an experimental physical chemist.

DeVorkin:

Before we get too far into Harvard, let's identify why you went to Harvard. Did you have other choices?

Roberts:

Why did I go to Harvard? Isn't that interesting, I don't know. I do remember. My professors at Amherst had consulted with me, and I had by then formulated my plan, and they thought Oldenberg was the best person. My physics professor, Ted Soller, knew Oldenberg, and thought if I wanted to go into physical chemistry from the experimental side, that that was the best place to go, that this man was extraordinary.

DeVorkin:

This is certainly the direction you were going: you were planning to have a career at Kodak. Were astronomy and physics more hobbies?

Roberts:

Well, Mees as you know was very interested in astronomy. I figured that I could be connected with astronomy, but I figured there'd be no jobs in astronomy. I figured you couldn't get a position that would pay you a salary in astronomy. And that was pretty much the case, then, too.

DeVorkin:

That was your parents' position too, I imagine.

Roberts:

Well, by then my parents were resigned to the fact that I was going to be a scientist. I don't think they knew aeronautical engineering from physical chemistry!

DeVorkin:

So then you did go to Harvard in the graduate program.

Roberts:

Yes. In physical chemistry. And I loved Oldenberg. He turned out to be an absolute marvelous teacher and human being. He was just absolutely great. And I took a course under Wendell Furry at the beginning of my first graduate semester in 1938 also, but I couldn't hack it. It was too tough for me, because it was in wave mechanical formulations and differential equations, where I was weak. I was strong in algebra and nobody taught Dirac there at all.

So I had to drop that course, and having dropped it, the only course that would fit into my calendar was a course in astronomy at the observatory under Donald Menzel. It was in spectroscopy. I figured it was perfectly good for my objective of going on in physical chemistry. You have to know spectroscopy anyway. So I took that course up at the observatory, and it turned out that Menzel was a miserable teacher, but the course was exciting. The reading material was good and I could understand it.

DeVorkin:

Do you recall how you decided on that particular astronomy course?

Roberts:

Oldenberg suggested it. I'd gone to him and shown him my calendar, and since I had to drop Furry's course, I wanted to get into something quickly before they got too far beyond me. He recommended that I take spectroscopy with Menzel. I took mathematical physics with Kemball, and I was able to hack that. That's when I began to learn differential equations and all that sort of stuff. I didn't have much in the way of calculus at Amherst. I just had a strong specialization in algebra.

DeVorkin:

Yes, that explains why you preferred Dirac. What about Menzel's spectroscopy course? Who were some of your student colleagues there? What excited you?

Roberts:

Just the material of spectroscopy excited me. There were four extremely good, helpful senior students in the thing. Then Menzel made a trip abroad and Leo Goldberg taught the course for a while, and he was inspirational. He was just absolutely great. Lawrence Aller, Goldberg, and James Baker were all there. They were two or three years ahead of me, but they were friendly and they spent a lot of time with me. Also, Ed Purcell in the physics department was extremely helpful to me, as was Charlie Townes, I think. Anyway I made three friends in the physics department, and then I made these three friends at the observatory, Baker, Aller and Goldberg. Whenever I got stuck they'd help me out.

DeVorkin:

Was it a course in observational techniques in spectroscopy?

Roberts:

No, it was theoretical spectroscopy. There was no lab work.

DeVorkin:

Was this akin to their long series of studies of radiation properties of gaseous nebulae?

Roberts:

Well, there were lectures about that, but it was not directly related. They did that book together with Menzel — Menzel, Aller, Goldberg and Baker. We were learning what spectroscopic notation was and forbidden transition rules and all that sort of stuff.

DeVorkin:

Right. Did you get into the Harvard College observatory atmosphere at all?

Roberts:

Yes.

DeVorkin:

Did you sense what it was like?

Roberts:

Yes, I did.

DeVorkin:

Could you describe it?

Roberts:

Let me go a little to the next step, because I transferred to the astronomy department in February.

DeVorkin:

On the basis of that one experience?

Roberts:

What happened was that Betty Capstaff jilted me. She went off to Europe and she fell in love with a man named Peter Phizackerly. She sent me back my fraternity pin that I gave her for the engagement. That happened around the lst of December and I was just absolutely, utterly devastated. I decided that there wasn't anything to live for in life, and I gave up my plan to work at Kodak — almost, not really, but I had that reaction — and I decided, well, I might as well go into astronomy. That's what I really love best and this course that I'm in is fantastic. It doesn't matter if I don't make a living.

DeVorkin:

Life was over.

Roberts:

Life was over!

DeVorkin:

That's marvelous.

Roberts:

So one afternoon I walked over to the observatory, and asked for an appointment to see Harlow Shapley. He sat me in front of that great big whirlagig desk that he has — have you ever seen that? His son Alan has it here in Boulder.

DeVorkin:

I've seen pictures of it, yes.

Roberts:

He had a section for each of his interests. He had Ants here, and he had Peace here, and he had Physics. He spun it around to the Ants and pulled out a bottle of preserved Ants and started talking to me about Ants. An hour and a half later, I was all gung-ho to go into astronomy. And I enrolled that day — this was towards the end of January — and it turned out that there was a rule there that every graduate student had to take the prelim written exams, three or four hour exams, every year they were in the department. I joined the department February lst and started the exams on February 2nd. I got the lowest grades ever given.

DeVorkin:

Well, they certainly knew that would have happened.

Roberts:

Yes. And I met Bart Bok, who is one of the most inspirational teachers that I've ever known anywhere, Freddie Whipple, Ted Sterne, Cecelia Payne-Gaposchkin, and Jim Baker, and Lawrence Aller as I said. Jack Evans had just left, who later became my best friend in the world.

DeVorkin:

He'd just graduated?

Roberts:

He'd just gotten his doctorate and gone off to Mills College where he had a job as janitor or something similarly menial.

DeVorkin:

And he got a job as a janitor at Mills?

Roberts:

There were no jobs to teach astronomy. And his wife got a job as a secretary. In six months he got a job as an astronomer, but he started as a very menial worker.

DeVorkin:

There was a 20 inch refractor associated with Mills at that time.

Roberts:

Right. They had a nice little observatory.

DeVorkin:

Did he use it?

Roberts:

I think so, yes.

DeVorkin:

It's not so bad, though, if you can sweep the floors and still have a telescope to play with. That's fine.

Roberts:

Yes, sweep the floor of an observatory.

DeVorkin:

What was the atmosphere like at Harvard then with all of these people that you mentioned, many of them advanced graduate students, friendly to you, looking for jobs apparently? Could you describe it?

Roberts:

Well, it was a very comradely sort of atmosphere. There were two Jesuit priests, Father Miller and Father Heyden, who is at Georgetown. I think he's retired now. Walter Miller went to the Vatican. Then there was Shirley Patterson and Rodney Scott — went to Perkin-Elmer later — and three or four others. Shapley used to hold a party once a month at his home, called the Lunatics. It was on the full moon, and they had Virginia reel square dancing and he would give a little short talk about astronomy from the broadest perspective.

The whole observatory staff used to have picnics together and we played tennis. They had their own tennis court there at the observatory. It was just a very, very warm friendly atmosphere. Oh yes, I met Annie Jump Cannon and Henrietta Swope, and AAVSO people, the Mayalls, Newton and Margaret, Sybil Chubbs and Leon Campbell, and just everybody. It was a warm, friendly family, and it was rather unlike the physics department. I took a course in physics, vacuum tube theory, under Chaffee, and there were two students in the course. At the end of the semester, he didn't know either of our names!

DeVorkin:

Slightly different.

Roberts:

Yes. That was his idiosyncracy, though. I met Howard Aitken, the computer guy—because of my interest in algebra — and took a course from him which was superb. He was very friendly. And also as I say, Oldenberg was marvelous and Kemball was really fine, but Chaffee was... But they didn't have all these parties and stuff. Oh yes, I also got to know, very well, Percy Bridgeman. I was interested in his philosophical ideas, the logic of modern physics, the idea of operationalism, all of that, which greatly influenced my life later. My best friend at Harvard was a man named Jim Balsley, and he studied under Bridgeman, so that's how I got to know Bridgeman. I also got to know Kirtley Mather, the geologist, very well. Jim studied under Mather, and Bridgeman, and so I went to their homes with Jim, and he went to the observatory parties with me.

DeVorkin:

Just quickly let me ask about the operationalism for future reference. Does it become important in your managerial work, in setting things up here, or in your larger work?

Roberts:

No, I think it was just in my feeling about the nature of science, what science means, the limitations of science, the need to live under uncertainty, and the fact that unless you can define an operation by which you measure something, you can't write a mathematical description of it. You've got to do it in terms of some defined operation. You can't just have great ideas about stars forming in space and coalescing in some way.

You've got to make a step-by-step, you might almost say mechanical operation by means of which you can measure and define it. That book really influenced me, and I also had some talks with him about it. I think I've still got the book there — isn't that the one, right behind your head, REFLECTIONS OF A PHYSICIST by Bridgeman?

DeVorkin:

There it is, right there, REFLECTIONS OF A PHYSICIST, the Philosophical Library edition.

Roberts:

I also met Gerald Holton later. Gerry wasn't there yet. But I met Fletcher Watson. He was the young one there, and he was interested in the philosophy of science and all that.

DeVorkin:

As far as the history of science goes at that time, only Sarton I think was around.

Roberts:

And I didn't know him.

DeVorkin:

In changing over, did you have any resistance from Oldenberg?

Roberts:

No. He applauded it. I went back to Kodak the next summer and talked to Mees and told him what I'd been through, and he said, "You just do a good job and it doesn't matter what field you're in."

DeVorkin:

That's right. After your first year, during your first summer — that would have been the summer of '39 — did you spend any part of your summer at the Harvard Summer School?

Roberts:

No. I was at Kodak the whole summer. No, I left the first day I could leave after exams and went to Kodak and stayed there until the day before school opened.

DeVorkin:

So you had no contact with those experiences?

Roberts:

No.

DeVorkin:

Okay. Let me just ask quickly, did you have any experiences with the Hollow Squares?

Roberts:

Oh yes.

DeVorkin:

Would you describe them?

Roberts:

Oh yes. In fact, we have Hollow Squares here.

DeVorkin:

You do?

Roberts:

Sure, which is adapted from the Harvard Hollow Square. I preserved that tradition in the High Altitude Observatory, which is now a division of this lab, and every now and then has a Hollow Square. They don't have them as often as they did when I was here.

DeVorkin:

Would you have any photographs of the Hollow Squares from Harvard?

Roberts:

I don't think so, but I can describe them in precise detail.

DeVorkin:

Please do.

Roberts:

They were in the library, which has a balcony around the top, and the tables were arranged in a Hollow Square. There was an opening in the center. People sat around the table, and in the chairs behind. Cookies and stuff were on the north wall; and on the east and the west side they also had chairs — the south had the projector screen and a few chairs. People also sat in the balcony. I remember Cecilia Payne-Gaposchkin always sat in the balcony.

DeVorkin:

Why so?

Roberts:

I don't know. She was a wonderful and a somewhat idiosyncratic woman. She used to boom down at the assemblage from the balcony. Somebody was to make a presentation, but also people were to make spontaneous contributions, and occasionally Shapley would ask a question of somebody that somebody wasn't expecting. Everybody participated, including the graduate students. They were to tell things that were going on at the observatory.

There would be a sort of introductory talk which would last maybe 20 minutes, and they were required not to speak at a highly technical level. They weren't allowed to use equations; they could use illustrations, pictures and stuff, but they couldn't do the thing you could do in a classroom, or in a seminar. They were to be understood by everybody including the secretaries.

DeVorkin:

Did the secretaries attend?

Roberts:

Yes, Sybil Chubb and — gosh, I can't remember the names of them all — Miss Harwood, and that lady that was later at Maria Mitchell Observatory.

DeVorkin:

Dorrit Hoffleit?

Roberts:

Dorrit Hoffleit was there, yes. Who was Whipple's assistant? Wonderful woman. Uglier than Dorrit, but such a lovely human being! Theodore Sterne was there. I thought Sterne was one of the best teachers I ever had, and he was an algebra buff, so I took everything I could with him, theory of statistics and every mathematics course that he taught. Martin Schwarzschild was there also as a student.

DeVorkin:

At this time, through publications, especially Theodore Sterne's interests, the source of energy of the sun was becoming known through Bethe's work. Were there Hollow Squares on that subject?

Roberts:

No. Hollow Squares were just on subjects that the observatory staff was doing. Visiting scientists would give seminars. The graduate students were allowed to pick one visitor. Shapley put up the money from the observatory budget to pick one visitor to come for a week and lecture. I was always an organizer, so I got the students one year to choose Charles Greeley Abbott, much to Shapley's disgust.

DeVorkin:

Why?

Roberts:

Because he thought he was an engineer and not a scientist. He came and talked to us about solar energy and about sunspots, whether there was a variation in the solar constant with sun¬spot cycle and so forth. Oh yes, and Karl Guthe was a graduate student. He was a close friend of mine in the department, and Guthe and I, under Sterne's direction, did what turned out to be my first scientific paper, co-authored by the three of us. It was on a periodogram analysis of the solar constant data to find out if there was evidence for solar cycle variations.

We did that in the basement of the Business School, using a Hollerith machine built by IBM, although they didn't call it an IBM machine yet. All it really was was a card sorter and a collator. Cards were read — they're the same cards that we use today — but they were read by wires that went through to a plate and pulled the cards out into the appropriate decks. Then we had a tabulator that would take sorted cards and tabulate them and add them. That is what we did our periodogram analysis with.

DeVorkin:

Was this in '39?

Roberts:

This was in, yes, '39. I think it started in the spring of '39 and finished in the fall of '39.

DeVorkin:

Now, these two things, first of all your interest in Charles Greeley Abbott, and in the periodicity cycles — what is the origin of this interest?

Roberts:

I had gotten interested in Menzel's work. Menzel was the solar man primarily. I really had great skill as a person to build things. I was not great shakes as a theoretician, but as an experimentalist I was really good. In fact, Oldenberg, when I did the experimental laboratory work — oh yes, my lab partner in Oldenberg's course was Harvey Brooks. Harvey was all thumbs but he understood it, and I couldn't understand it but I could build anything. So between us we got through. (Harvey doesn't like to be told he was all thumbs. I said that once up at Aspen and he said, "Oh, I wasn't all thumbs at all I built many of those experiments.") But he was all thumbs but really brilliant in theory.

Anyway, Menzel had been to France in 1935, and had seen Lyot's coronagraph, and he wanted to build one. He's a Colorado boy and he wanted to put it on a high mountain in Colorado, and I got really inspired by this idea. So I studied up and read the papers that were available (there wasn't much) about the coronagraph. Menzel got a grant from, I think, the U. S. Department of Agriculture for about $5,000 to build the coronagraph, and he hired a guy named Hobart French who I think later became a camera designer for Argus, or maybe it was the company that made that little mercury shutter. Anyway he later went into camera design and left the observatory, and when Hobart left the observatory, I inherited the unfinished coronagraph. I went to work.

I then took an assistantship with Menzel to work on the coronagraph, and I decided that was going to be my thesis project, to build and operate the coronagraph, and so I threw myself into it. I really was good with optical stuff and mechanical stuff, and essentially built the coronagraph with my own hands, from the pile of parts, many of which didn't work. The truth of the matter was — I wouldn't want to say this publicly — but Menzel didn't really know how the coronagraph worked in detail. He didn't understand all its optical principles. It was originally put together wrong, so that it wouldn't have functioned at all. But I figured that out, and we got it working at Oak Ridge: that was the observatory station.

DeVorkin:

So there was a working coronagraph at the Harvard station in the spring of '40. That was the first one done in the United States?

Roberts:

Yes. Somewhere I still have some photographs we took with it out at Oak Ridge of solar prominences.

DeVorkin:

Do you have photographs of the instrument as well?

Roberts:

We have a photograph of the instrument also in a historical display at NCAR.

DeVorkin:

Did you construct the optics or were they made commercially?

Roberts:

No. I forgot to mention that when I was hunting jobs originally at college, I also made a close frienship with Harold Moulton, who was head of research at American Optical. I had an alternate offer to Kodak from American Optical to go to work that first summer, which I didn't, but I kept the option open by going to visit a couple of times at American Optical, because I still had this very high interest in optics. So, through my friendship with Moulton, American Optical made the first objective lenses for the coronagraph.

DeVorkin:

In the Lyot design, this was a large single lens?

Roberts:

Yes, it was an aspheric, single element lens. You couldn't use two elements because of the problem of scattered light. Moulton understood the problem and searched for an extraordinarily fine glass blank that was free of bubbles and stuff, and then had it ground to meet the specs for the coronagraph. It was only four inches in aperture, but that was big considering the quality of glass required.

DeVorkin:

Does that coronagraph still exist?

Roberts:

No, that was accidentally burned up as scrap. I lent it to Lockheed, and they accidentally condemned it. It's been destroyed.

DeVorkin:

You mean the Lockheed Solar Observatory in southern California?

Roberts:

Yes. I lent it to them after we built a new one, and when they dismantled it, they junked it. Too bad. The spectrograph still exists, and that's around here somewhere.

DeVorkin:

A Littrow?

Roberts:

Yes, it's a Littrow.

DeVorkin:

Heavens, I'd love to be able to identify that.

Roberts:

I think it's either in the physics department or it's in the High Altitude Observatory. I think we could find it. It sat in the corridor out here for a couple of years, as a museum piece.

DeVorkin:

Good. You can understand, being from the Smithsonian, we're interested in artifacts.

Roberts:

By the way, that Littrow, not the rest of the coronagraph, but the Littrow went to the 1935 eclipse in Russia. It's made of magnesium, to be light, to travel.

DeVorkin:

That's very early for a thing to be made of magnesium.

Roberts:

Yes, it is. Dow made the magnesium specially for the Littrow.

DeVorkin:

That must be one of Menzel's instruments.

Roberts:

That was one of Menzel's instruments. Then I attached it to the coronagraph to be the spectrograph of the coronagraph.

DeVorkin:

Again, as far as the original coronagraph goes, the four inch aspheric lens does not exist.

Roberts:

No.

DeVorkin:

That was junked.

Roberts:

That was junked. Everything was junked. Of course, that original four inch lens we only used for a short while, because then Jim Baker took an interest in it, and with his exquisite optical skills, he made us two objectives. It's almost impossible with a coronagraph objective to avoid scratching it. He had to clean it every day or every few days, and I learned the technique of cleaning from correspondence with Lyot. You had to put a monomolecular layer of grease on the surface of the glass. But we didn't have those synthetic monomolecular layers then, so we used face grease.

What you did is, you carefully washed your face, then after about an hour, making sure that you didn't get into a dusty environment, you took your finger, rubbed it on your face and touched it two or three places on the surface of the lens. Then, using a thoroughly laundered baby's diaper that had been laundered maybe 30 times so that it was soft, you gradually spread that layer of grease over the entire surface of the glass, which made it possible to remove dust without static electricity bringing the dust back to the surface. And later, of course, we developed all kinds of stuff you spray on, automatic cleaning processes, but that's the way the early one was cleaned.

DeVorkin:

So that's how you generated this.

Roberts:

Face grease and baby's diapers.

DeVorkin:

Oh boy. I see. Now, the two lenses that Baker then later provided, do they exist?

Roberts:

I don't think so. The original American Optical lens went almost in the first year at Climax. Baker's lens, which was five inches, I think, then went in. Baker made two lenses. One was kept as a spare. But I don't know where those lenses are. I haven't any idea, but I imagine they went to Lockheed, because they used the telescope for two or three years. The guy at Lockheed was really upset when he realized that they had accidentally scrapped it. We first put it up at Oak Ridge and ran it. There were some pictures in SKY AND TELESCOPE of that Oak Ridge installation, and also of the first prominence pictures. They weren't very good. Of course we didn't see the corona with it. You wouldn't be able to see it from Cambridge unless it was just an extraordinary day, and also the corona extraordinarily bright.

DeVorkin:

But you could see the prominences.

Roberts:

The prominences, yes.

DeVorkin:

I'd like to try to recreate your feeling when it first worked successfully.

Roberts:

Oh God, it was exciting! It was exciting! Menzel and I were both out there, and really just jumping around like kids, when we could see the prominences, and then, photographed them. I developed the films, and saw them on the negatives — it was quite a thrill.

DeVorkin:

What kind of filter were you using?

Roberts:

Way back then in Cambridge, we were just using some Schott filters — I think they were called RG 2 filters — and a film that cut off on the other side.

DeVorkin:

So you were after calcium lines?

Roberts:

No, it was H alpha. We had a very broad band between the film sensitivity and the filter. We must have had 300 angstroms or 200 angstroms, but the prominences were bright enough to show up, and we didn't have the spectrograph connected so we didn't look at the spectrum. But of course it's easy to see the spectrum of prominences anywhere. We got direct photographs of the prominences with the filter and got a few sequences, showing motion on the prominences. But we regarded that arrangement simply as a preliminary set up, to make sure we had all the parts) that everything was ready to go to Colorado.

This was spring of '40, probably March of '40, that we had it set up at Oak Ridge, and I think we took pictures with it only three or four times there. Then we started packing it up to be shipped to Colorado. Menzel had come out the year before to Colorado and made arrangements with the Climax Molybdenum Company to build an observatory in the Climax town, at the edge of the mine. My wife and I were married in June of '40.

I forgot to say that my mother arranged a blind date, in February of 1939, that time when I was so despondent. Jim and I used to go out to my mother and dad's farm every week end that we could get away from school. She arranged a blind date for him and for me for a particular week end out at the farm, and I married my blind date and he proposed to his blind date, but she didn't accept him.

DeVorkin:

You were considerably luckier. Had Menzel done any site surveying for different areas?

Roberts:

Not much. In '40, you could not get the infrastructure to run an observatory at a high altitude in any but a very few places. Climax was one of them. They had electricpower, water, snow plowing and all of that. Also, Menzel had grown up in Leadville so he knew that you had a number of really brilliant clear days, so he didn't really do any thorough site survey. We talked idly about Hawaii, but the transportation to Hawaii was so horrendous.

There were no flights to Hawaii, or maybe those Pan Am Clippers flew at that time, I don't remember, but it would have been impossible to maintain a station in Hawaii. There was no other station of even remotely similar altitude that was available in the U.S. So Climax was an easy choice. My wife and I were married in June of 1940. At the end of June or lst of July we packed most of the coronagraph into an old Graham Paige car and drove to Colorado.

DeVorkin:

What was the story of that Graham Paige? I understand that was from Shapley?

Roberts:

Yes. The observatory offered to give me the money to go out by train, and to ship the coronagraph by train, and I asked them if I could take the same money and buy a car, and that we could carry most of the coronagraph in the car, and he said, "Why not?" I think I bought the car for $125.

DeVorkin:

So this wasn't Shapley's car that he gave you?

Roberts:

No. I bought the car in Boston, and it got as far as Wellesley before it broke down. I remember, we drove through Pontiac, Michigan, in order that I could see and meet McMath and see the McMath Solar Observatory, which was the world's greatest prominence photographing setup. We broke down on the outskirts of Pontiac, and they had to rescue us with the observatory truck. We finally broke down for three days in Hastings, Nebraska, and I was out of money by then to repair the car, and so I wired back to Cambridge asking Shapley for some money, and he sent it.

DeVorkin:

That's good. The McMath Holbert of course used a spectroheliograph for their prominence work, so really this was the first coronagraph in existence in the United States.

Roberts:

That's right. There were three in the world.

DeVorkin:

There were three?

Roberts:

Lyot's in the Pic du Midi and Max Waldmeier in Arosa, Switzerland.

DeVorkin:

So it was certainly very experimental, and it was this first coronagraph that you had built with Menzel at Oak Ridge that you transported to Climax.

Roberts:

Right.

DeVorkin:

This was your Ph.D. thesis?

Roberts:

It was intended to be, yes.

DeVorkin:

Was it intended that you would build it and then do something with it, or was it to be just the building?

Roberts:

No, it was to observe the sun's corona.

DeVorkin:

And what particular questions were you asking?

Roberts:

Well, you have to remember that in 1940 the coronal green line was not identified. It was called coronium, and was believed to be an element unique to the sun, and the great dispute was over what the temperature of the corona was. Menzel was a high temperature man, from his theory of nebulae, presented in Radiation Processes in Gaseous Nebulae, that book that he did with Aller, Goldberg and Baker.

He was of the opinion that the corona had a very high temperature, but nobody had suggested the identification of the green coronal line, so the mystery of the green coronal line and the other coronal lines still remained. S.A. Mitchell had gotten some beautiful flash spectra, prior to that, during eclipse. I think he had done that maybe as late as '34 or '36, so we knew pretty much what the spectrum was, but we didn't know the identification of these very, very broad lines. The prevailing theory at the time was that the broadening was due to the radial velocity in the streams coming out from the coronal regions, in a range of directions, and that it was a velocity broadening rather than a thermal broadening, and so, solving the mystery of the identification of the coronal lines was one main problem.

Another problem was that Menzel was convinced that if the corona was of extremely high temperature, it would be influential in affecting the ionosphere and radio communications and all of that. He had an intuitive sense that solar activity affected the weather, and it was on that basis that the Department of Agriculture had made the grant, under Henry Wallace, when he was Secretary of Agriculture.

DeVorkin:

There was a controversy, of course, as to what was causing the ionosphere, ultraviolet or X-ray radiation, and that could have told you two very different things about the sun. In the late thirties, Shapley brought in from time to time people like Saha and O'Brien.

Roberts:

I remember meeting Saha.

DeVorkin:

Oh, you did? Great. And Brian O'Brien.

Roberts:

Yes, Butch O'Butch.

Roberts:

We called Brian O'Brien, Butch O'Butch. Jack Evans went to work for Butch O'Butch, after he got his wartime project going.

DeVorkin:

Well, what I would like to know from you is, if you have any recollections of the controversy over the nature of the solar continuum in the ultraviolet.

Roberts:

I don't really remember that. The first sharp memories I have are when C. W. Allen and van de Hulst first gave what we now know to be the correct theory of the electron corona, the emission corona and the Fraunhofer line or "dust" corona.

DeVorkin:

This was already '49, '50, after the war?

Roberts:

It was '47, as I remember. I remember vaguely those controversies but I don't remember them clearly.

DeVorkin:

Do you remember O'Brien and Saha talking about the need for a stratospheric laboratory?

Roberts:

Yes.

DeVorkin:

What were your impressions of that?

Roberts:

I don't have much memory. I remember the flight of Anderson, the balloon flight to the stratosphere. But I don't have any memory of the stratospheric observatory proposal.

DeVorkin:

The reason I bring it up is not so much for specific infor¬mation about it, but for your impressions of it, whether hearing about this was influential on anything in your later work.

Roberts:

No. The big thing was the ionosphere and the corona, and the identification of the coronal lines, and what we used to then call the corpuscular emission of the sun, what subsequently became the solar wind, when Eugene Parker invented the term. I almost did that myself about a year earlier, but I didn't quite get the handle on it. Not the name but the theory.

DeVorkin:

This would be in the mid-fifties?

Roberts:

Yes, '56.

DeVorkin:

Those were the primary concerns?

Roberts:

Yes, right.

DeVorkin:

Let me ask about the source of the coronal line, the identity of it. Everyone had known by that time certainly of Bowen's fluorescence mechanism for nebulae. Didn't Menzel ever take that example and wonder whether it could be very highly ionized, forbidden elements?

Roberts:

Not to my knowledge. All of that was done by Grotrian and Edlen. Grotrian had the hunch about it, and even made the suggestion that these highly forbidden transitions could occur; that is, there would be lines in the visible which would be from the very highly ionized iron and so on. He even made a tentative identification of one line, one particular transition, I've forgotten the details. Edlen, moving from that, showed the sequence of lines, and that it all fit together. But remember, it was during the war, when communi¬cation was very poor. I remember when we finally got hold of a copy of Edlen's paper.

DeVorkin:

When was that, '44, '45?

Roberts:

It was during the war, I think. It was probably '44. I got a letter from Lyot, smuggled through from Spain, with a tremendous amount of information, and also mentioning Edlen. You may remember K. 0. Kiepenheuer was a prominent German scientist, and he was the scientific advisor to Hitler and Mussolini at their famous Brenner Pass meeting. Later he was put in charge of science in occupied paris, and he had claimed – a very complex man and I knew him extremely well; he's dead now — to have saved Lyot's life and that of Lyot's colleague, Gentili, by allowing them to escape to Vichy France and then to Spain. I don't know if that's true.

He had such a guilt sense over his participation with Hitler and Mussolini that he lived a life of anguish. He told me that for at least five years he couldn't sleep at night. He was trying to do all kinds of things to justify what he had done. So, whether he made that story up or whether it's real, I don't know.

DeVorkin:

Why was Lyot's life in danger?

Roberts:

He was a Jew, and he was very prominent in the Underground.

DeVorkin:

Oh, that's a bad combination.

Roberts:

He and a guy named Gentili worked together in Paris at the observatory with D'Azambuja who was non-political, but Gentili and Lyot were activists against the Germans.

DeVorkin:

About Kiepenheuer, Kuiper was in the Alsace mission to Germany, and in his letters, not in his report, but in his letters back to Struve, which I recently read, he said that Kiepenheuer was one of the few who was not a Nazi, never joined the party. Is that correct?

Roberts:

I think so. At least that is what Kiepenheuer has told me, and I also talked to Unsold about it, and I talked at length with Leo Szilard, who became one of my very close friends. I forgot to mention, a sideline. There's a fellow named Stephen MacNeill with whom I worked in the development department at Kodak, and when the war broke out, that whole group went to Tennessee Eastman and worked on the U235 bomb. They were in the bomb development group.

DeVorkin:

The chemical diffusion people.

Roberts:

Right. Through them, during the time I was at Climax, I made a couple of trips back and did just a little bit of consulting and got informed about the progress of the work on the bomb. I was informed about the bomb, and the objective of it.

DeVorkin:

You certainly had security clearance at that time.

Roberts:

Yes. Because the work I was doing was classified. My Ph.D. thesis got classified before I got it finished, and that's why I didn't have my degree till '43.

DeVorkin:

I see. Was that the first classified thesis in astronomy?

Roberts:

I don't know.

DeVorkin:

Might have been. I'd like to go back before we forget about it and talk a little more about Kiepenheuer, could we do that?

Roberts:

Sure.

DeVorkin:

My interest in him is through his setting up of ionospheric stations, and also through his close contact with ...

Roberts:

and setting up of coronagraph stations.

DeVorkin:

And setting up coronagraph stations?

Roberts:

He got Zeiss to build 20 or 40 coronagraphs. I think only three of them ever got finished, but one went up on Kanzelhohe, that's a mountain in Austria, and another on Wendelstein in Bavaria.

DeVorkin:

How about Jungfrau?

Roberts:

No, they didn't have one at Jungfrau. Just those two got set up, and there was a third one that was being tested and operated at low level. They were convinced that the daily observation of the corona contained the secret to radio communication. We're ahead of the story, because this is what I discovered from the first half year of coronal observations that 1 made, and also J. H. Dellenger simultaneously. It had been hinted at in a paper by Waldmeier. He made some comments about it. But that was still before we knew the high temperature of the corona, before it had been verified.

DeVorkin:

Kiepenheuer had extensive contacts with Eric Regner.

Roberts:

I knew Eric Regner also. I visited there with Regner at his home, right after the war — introduced by Victor Regner, who was at Chicago and became a close friend when he did cosmic ray research at our Climax Observatory in the early war years.

DeVorkin:

Do you have any recollections of their discussions of their attempts to send spectrograph instruments in V-2 rockets?

Roberts:

No. I never talked with them about that. I did work with Richard Tousey setting up ultraviolet spectrographs at White Sands, and I nearly got killed in a rocket explosion at White Sands.

DeVorkin:

We must talk about that later. That's amazing. Funny, he never told me about that.

Roberts:

I don't think he was there on that day.

DeVorkin:

I also know that Tousey visited Climax early on, and that there were many early attempts in Europe, on the Jungfrau and other places, to get beyond the 3000 angstrom barrier, to get down at least to the predicted magnesium doublet and things like that. I'm wonder¬ing what contact at all you had with this kind of activity, prior to the war, during the war?

Roberts:

I didn't have any prior to the war, and only after the war did I have contact through Richard Tousey and Herb Friedman and some of those others. The Sac Peak Observatory came about because of the enthusiasm of Menzel and also Marcus O'Day, of the Air Force Cambridge group. He was director of AFCRL. It was then called Geophysics Research Directorate, DRD. They wanted to have an observatory connected with the rocket range at White Sands, so that's how I started working in the Sacramento Peak area. Menzel and I went down in about '47, might have been even '46, to White Sands, and got a military vehicle, and searched all through the White Mountains, all through the Sacramento Mountains, for an observatory. We jointly decided on the present location of Sac Peak, drove a stake in the ground and said, "Here it is." But I didn't have any real connection with the ultraviolet spectroscopy business.

DeVorkin:

Okay, but I would very much value your views, your recollections of what was going on, how valuable you thought it was. Whether you thought it was premature or whatever.

Roberts:

Later I got very interested in that, but that wasn't until quite a bit later, when Jack Evans and I built the sky photometer and flew it in an airplane to see how low you could get, and then later used Schwarzschild's balloon platform to fly a coronagraph up to 100,000 feet.

DeVorkin:

Right, the coronascope.

Roberts:

That instrument is down in the lobby. We'll see if we can find the old corona spectrograph.

DeVorkin:

Let me ask a few questions about the design of coronagraphs. Certainly reducing scattered light was your primary problem. Would you say this was really the primary need of a coronagraph?

Roberts:

Yes. It would be more proper to call it parasitic light, because it wasn't just scattered. You wanted to get rid of light from the photosphere of the sun. You had first to go to a place where, as much as possible, the atmosphere didn't scatter. Secondly, you had to use an objective lens that was free of blemishes and dust. Then thirdly, you had to get rid of the reflections that come from surface 2 to surface 1 of the objective, and then back into the system. Because light traversed the lens twice, it is brought to a different focus, and so, the secondary optical system of the coronagraph is designed entirely for the purpose of getting rid of that false image.

That's a trick, because if you don't do it right, you vignette the image. You vignette it a little bit anyway, but in the ideal you can minimize that. Then there's the third source. The third source is diffraction around the periphery of the objective. When you re-image the objective on the secondary system, you make a diaphragm that's smaller than the image of the objective, and cut out the bright diffraction ring. Then you've gotten rid of the internal reflections, diffraction, and by having a clean lens in high altitude, you've gotten rid of scattered light.

DeVorkin:

Did you appreciate all of these things from reading Lyot's papers?

Roberts:

Well, yes, mainly, but I also had to figure some of them out.

DeVorkin:

What were the aspects that Menzel did not appreciate? Do you recall?

Roberts:

Yes, he didn't understand the function of the secondary optical system to get rid of the diffraction from the objective, or of that double reflected image, even though it was in the original Lyot paper. It was in the paper but I don't think Menzel read French very well, and I did read French well, and moreover, it wasn't very clear. The explanation wasn't very good, and it was that letter I got from Lyot, which was in response to a letter I'd sent him with some questions, that helped me, although I'd already figured it out.

That letter helped me greatly. I invented a gadget which I had discussed with Lyot. Even with the best lens, you don't get rid of all the scattered light; there are still blemishes and stuff, and each one causes a diffraction around the dust or whatever. What I did was make a photographic diaphragm by photographing the objective when it was illuminated by sunlight, then making a template from that which blocked out the diffraction of each blemish individually. Then I inserted that in the focal plane in the secondary optical system, and it cut down the light transmission maybe 20%, but it got rid of another substantial source of scattered light. That's what I discussed with Lyot. That screwed up the wave fronts, such that the image wasn't very good. That's what I didn't understand. That's where Lyot helped me out.

DeVorkin:

I see. Did you retain that letter from Lyot?

Roberts:

I gave all my letters to the university, and they're collected and catalogued.

DeVorkin:

Great.

Roberts:

So I don't remember whether I have that letter. I think I gave it to Menzel, and he didn't keep anything.

DeVorkin:

So your correspondence, your working notes from that period are now at the University of Colorado?

Roberts:

Well, my secretary has a catalogue, and I think it includes everything I could find when I decided it was important to try to keep it.

DeVorkin:

I would like to have a copy of that catalogue if I could.

Roberts:

All right, she can give you that.

DeVorkin:

Great. Could you review your first few years. We were talking about the design of the coronagraph, the photographic filter that you had designed. Was this your contribution?

Roberts:

No, this was just something fairly obvious. We are talking about the one back in Cambridge now.

DeVorkin:

Yes.

Roberts:

Now, the filter that really opened it up was the filter made by Jack Evans. I came out to Colorado, and it was really almost 14 months before I got the coronagraph to really work. First of all, Jack Evans made two birefringent filters. They were very complicated devices consisting of layers of quartz and half-wave plates and all that sort of stuff, which had a transmission of 4 angstroms, and the band, the wavelength of the peak of the transmission was controlled by thermal means. You heated it up to move it to the red and cooled it down to move it to the blue, or vice versa.

I don't remember which. But it had to be accurately thermostated, and I forget now whether I built the jacket and thermal control or whether Jack built it and gave it to me. He was working with Brian O'Brien at that time at Rochester at the Institute of Optics, and he made it partly in his home basement and partly at the Institute of Optics, and gave it to us for use at Climax. That allowed us to photograph the H alpha line of hydrogen for prominences. The filter had a whole bunch of peaks, not just one, and the peaks were far enough apart that you could isolate an individual peak with film and filter, and with the proper film and filter you could also isolate the green coronal line at 5303 A. I got the birefringent filter—I can't remember now exactly when—probably in the fall of 1940 or it might have been the spring of '41.

DeVorkin:

You were already there?

Roberts:

I was there from July 1940 on. But they had to finish the observatory. It hadn't been finished when I got there. Then I had to erect the instrument, had to pour the concrete, and then after they got the thing up, the dome rotation didn't work, and the gears ground off on the wheels that drove the dome, and there were all kinds of problems like that.

DeVorkin:

Was this the original cone shaped dome?

Roberts:

Yes. That one.

DeVorkin:

The one on the right in the picture on your wall.

Roberts:

Not at that location, by the way. At a different location. About five miles from there.

DeVorkin:

To what degree were you overseeing the construction of the first buildings? Were you involved?

Roberts:

No, I wasn't directly involved. Menzel had that mostly done by the time I got there. But I did have to oversee the construction of the pier for the telescope. Then the dome broke down so it wouldn't rotate, and I had to manage the repair of that, get that to work. Then there were a lot of other problems, just silly things like not having any water, electric power would quit, and so forth. I had a machine shop with a lathe, a band saw, a router and drill press, things like that, and a lot of hand tools, and essentially I had to build the instrument there.

The electric drive that Hobart French had designed quit in the first month, and I had to build a totally different electric drive. The gear train was gear driven to follow the sun, and the gear train didn't mesh correctly, so that the thing wobbled back and forth when the wind blew, so you couldn't keep the sun eclipsed. All kinds of things like that, that I had to worry about and fix.

DeVorkin:

So Hobart French's work was mainly in the mechanics of the spar?

Roberts:

Yes. It's something that he would have been able to fix. He was a genius at that sort of stuff. But he left before it was ever put together.

DeVorkin:

Evans?

Roberts:

No, he went to Mills. Then he got the job at the Institute of Optics, University of Rochester, under Butch O'Butch.

DeVorkin:

So that was where he was able to make the birefringent filters.

Roberts:

He started the birefringent filters at Mills, and I think he had the first one finished at Mills and tried it out on the Mills telescope. That's my memory anyway.

DeVorkin:

Can he be classed as the discoverer of this technique?

Roberts:

No. There was a different version invented by a man named Schultz, the original one. The birefringent filter probably was invented by Yngve Ohman. I'm not sure of this. He was an astronomer at the Stockholm Observatory. He's still alive but very old now. He came over here to the High Altitude Observatory for a year as a consultant in the late forties. He was either the inventor or the developer of the ones that worked for astronomy. I don't remember which. I think the birefringent filter had been invented earlier for another purpose.

DeVorkin:

So the idea was simply to be able to have one to be able to provide this-, very clean filter.

Roberts:

Yes. It provided this very narrow band filter. There were not any optical film combinations that would give you a band less than few hundred angstroms or maybe a hundred angstroms. This filter could bring you down, nowadays, to a tenth of an angstrom, but in those days four angstroms was considered a fabulous filter. They were not very efficient of light. Jack made a development later that doubled the light power of the thing. But they had about 20 elements in them and they were slow.

DeVorkin:

Had you ever considered using a monochrometer as a filter?

Roberts:

You mean a spectrograph?

DeVorkin:

Yes.

Roberts:

Yes. It would have been like a spectroheliograph in a way. But it didn't seem to be the way to go. Later we did build some of those at Sac Peak.

DeVorkin:

So within a number of months you received this birefringent filter, and then what were the steps after that?

Roberts:

Well, I was struggling to complete the Littrow spectrograph and get it in operation. On the coronagraph there was just a pipe coming out of the rear end. I had to build a device that was movable, that would focus up and down. Also you had to get access to the top, so you could adjust the optical components. In the original coronagraph you couldn't get at the secondary optical system where you did all that complicated imaging and so on. You couldn't adjust anything. You couldn't even see it to adjust it. So you had to have it open. That's why we developed the philosophy of the spars like the one at Sac Peak, where all the optics are on the outside, and the light doesn't go down the middle, it just goes down the outside.

DeVorkin:

So the spar is your development. Lyot didn't do that.

Roberts:

No, Lyot didn't do that and Menzel didn't have that in the original design, and I made an intermediate design in which there was a three-sided channel in the back that could be moved up and down, but you could open covers and get your hands into it. Then later Jack and I, working together, developed the spar concept and built the 26-foot spar at Sac Peak and a similar one at Climax, and built a 10-foot spar that's operating right outside here now on the south side of the building.

DeVorkin:

Oh really?

Roberts:

Yes, and by the way, he also developed the roller drive.

DeVorkin:

The what?

Roberts:

The gearless drive. It's driven by rollers, and the inspiration for that came to me one day in Jack Evans' house here in Boulder. I was fixing a phonograph motor and I saw that it used this principle. Jack and I decided that you had to have one fixed wheel, and another fixed wheel, and then you have an idler that you spring-load in between them, and that makes a sort of a gear train. That idea came out of a phonograph motor. I'm not sure whether Jack first saw the light or I did.

Roberts:

We were at that time designing the first postwar coronagraphs, and we were thoroughly dissatisfied with the kind of gear drives that we had.

DeVorkin:

With their chatter or the rocking?

Roberts:

Just the rocking. The coronagraph had to be guided with an accuracy on the order of a second of arc or two seconds of arc, in order to avoid the flashes of light that would come. You've seen some of the early movies? On a windy day, they're all bothered by flashes of light, and that's from the gear train. Let's see — where were we? I've lost track.

DeVorkin:

Well, the roller drive, development of the spar, all of the aspects of the coronagraph that you and Jack Evans developed. Roberts Yes. Jack came to work at the observatory in February 1946. For the first month we didn't have a single clear day, and finally we had enough clear days in May and April that Jack learned how to run the coronagraph. I instructed him on how to run the coronagraph. On the 4th of June he started to run the coronagraph alone for the first time, and that's when that granddaddy super solar prominence, largest prominence ever observed, occurred.

DeVorkin:

Oh, that monster.

Roberts:

That huge monster. In the last two years or so we've gotten bigger ones, but up till then and until recently, that was the biggest. Jack came in from the observatory, and said, "You know, I'm going to run the coronagraph today, but what do I do when the prominence is too big for the picture frame?" I said, "Oh, that never happens. Forget it." He said, "Well, you'd better come and take a look." I looked through the eye piece and nearly fainted. I got him out of the way and took that movie, because I knew how to do it and he would have done it slowly. Then I developed the movie, and I couldn't believe it when I saw it, what was on it, because when I finished taking the film, that's the first time I could look into the coronagraph again visually. There wasn't anything there. So the whole thing developed and blew right out of the top on the picture frame. When I developed it and saw the image, I was so thrilled, I just absolutely couldn't believe it!

DeVorkin:

I'm sure I've seen that. That's the great arc that spins away.

Roberts:

Yes. DeVorkin; You took that film?

Roberts:

I took that film. Jack took the first two or three pictures of the prominence in its early stage, and then called me, and I took the movie with his help.

DeVorkin:

Incredible! Certainly if he came in '46, we have a number of years to cover, the war years.

Roberts:

Right.

DeVorkin:

We have to cover the development of HAO, development of staff and direction.

Roberts:

Yes. I finally succeeded in getting the coronagraph and spectrograph all working by about July of '41, and started taking routine photographs of the corona, and making maps of the coronal brightness, all the way around the periphery, in the red line and the green line, 6374 and 5303. This was of course to be my thesis, and I had hoped to finish my thesis after I had six months to a year of observational data. This was the first real work on my thesis; I was going to study the morphology of the corona, and the way that it rotates with the sun — does it co-rotate with the equator, or how does it rotate relative to the surface, and how is it related to prominences and things of that sort.

I started routine observation every clear day, and in November I had enough data to do some statistical work and so on. Jonathan 0. Fleming was director of the Department of Terrestrial Magnetism, Carnegie Institution of Washington, and H. J. Dellinger was at the Bureau of Standards, I think. Now, Dellinger was interested in ionospheric radio propagation, as I remember, and he wanted the coronal data, so every week or so I'd bundle up the maps that I'd made of the corona and send them off to Dellinger.

I would also work on them myself, and by November, I realized that three or four days before a radio fade-out and ionospheric disturbance, on the average, we had bright corona suddenly appear at the east limb of the sun. I realized that this was quite an exciting and important finding, and I communicated a letter to Dellinger, which I think, if my memory's right, actually crossed in the mail with a letter from Dellinger who had found the same thing. This was a few days before Pearl Harbor, and instantly after Pearl Harbor the subject got classified. Now, I had had my thesis almost done. No, I beg your pardon, it wasn't instantly classified. I'd had my thesis almost done and had set a February lst deadline to have it finished and submitted to Harvard, and then go back and take my final exams and get my doctorate.

DeVorkin:

This would have been February of '42.

Roberts:

February of '42. After the thesis was finished and transmitted to Harvard, the whole project was classified, and my thesis was classified. It wasn't a very high classification. It was classified "Restricted", because I did have a description of the radio fade-out business in the Results chapter of my thesis. I didn't go to take my exams, and we started a program in which I coded into a secret code the coronal information, measuring the films before they were even dry, to give the location and strength of the strongest coronal regions at the edge of the sun, and transmitted that along to the Department of Terrestrial Magnetism, to J. A. Fleming.

Very quickly, very soon in the war, that became a military project under the Joint Chiefs of Staff, and subsequently became the Interservice Radio Propagation Laboratory, which was set up in the Bureau of Standards, with J. Virginia Lincoln, Alvin McNish, Alan Shapley, Harlow Shapley's son, who had been a friend of mine at Harvard when he was an undergraduate and was interested in astronomy, and Dana Bailey, who was I guess a U. S. or Canadian military officer, attached to the Joint Chiefs, and two or three others. So I was more or less frozen in my job and had to stay at Climax. I remember, I once spent 18 months without leaving Climax!

I took observations every day, and I worked alone. I was the whole staff. Then, towards the end of the war, they sent a Navy lieutenant out to be an assistant, and we also got a couple of additional people as assistants at the observatory, so I had a staff of four or five by the end of the war.

DeVorkin:

Did you have any choice as to who would be the assistants?

Roberts:

The local ones, yes. I chose them. But the Navy lieutenant was just assigned by the Navy. He was interested in astronomy and he got a doctorate in astronomy later.

DeVorkin:

Who was that?

Roberts:

Louis Larmore, and he is to this day a friend of mine and interested in solar astronomy. He works now as a civilian at the ONR in California.

DeVorkin:

Who were the locals?

Roberts:

One of them was the daughter of the mill superintendent of the mine, and one of them was the daughter of an underground superintendent, and one of them was from Leadville.

DeVorkin:

So these were not professional physicists or anything?

Roberts:

No. They were just helpers. One of them was a woman named Lynne Prescott. Her husband was at Camp Hale, and she was a runner-up for Miss America. She was a beauty, and a woman of great intelligence. She was my most beautiful assistant. When the war was over, she was stationed in Iran for something like six years. Lovely people. I've kept in touch with them all these years.

DeVorkin:

What was your degree of success in predicting radio fade-out?

Roberts:

Well, it was pretty high. Not so strange a mystery, because after the war, that relationship was not as reliable as a predictor. So we began to realize after the war that something else was operative, and we didn't have the whole story. At the time the relationship looked rather simple and clear. It's something like the story of the Battle of Britain and the radars. If solar activity had been a little higher, a little sooner, England might have lost the war because the radars would have been blanked by the solar radio noise. When the solar activity was moderate, as it was then, the relationship of ionosphere and corona was a good one. I would say we were able to predict something like 70%. That's a crude guess. Of course I didn't really see the applications of it. It ended when I sent them the telegram with the coded information.

DeVorkin:

So your contacts were through DTM and the Interservice Radio Propagation Laboratory. Did you have a direct military contact?

Roberts:

It was the Interservice Radio Propagation Lab. Their job was to forecast radio communications.

DeVorkin:

Did you ever know of a fellow named Richard Silberstein at Interservice?

Roberts:

Sure. I knew him well.

DeVorkin:

I'm very interested in him. Is he still alive?

Roberts:

I think so. I think he lives in Louisville. Alan Shapley can tell you for sure. He lives in town here and worked with Silberstein.

DeVorkin:

Silberstein wrote a proposal for the use of V-2s earlier than anyone else I've ever seen.

Roberts:

Is that so?

DeVorkin:

Before they were even here. I ran across that proposal, and I'd really like to talk to him about it. So he had continued working at the National Bureau of Standards after the war.

Roberts:

I think so. I think he came out here when this became the Interservice Radio Propagation Lab here in Boulder. I think Dick just retired two or three years ago.

DeVorkin:

I wish I'd known he was here. I have his proposal in my office. It's really quite interesting.

Roberts:

Do you know Dana Bailey? Well, Dana did an incredible thing while he was in the military. He did a proposal that set up a big project for a forward scatter propagation, which would work in the midst of an ionospheric disturbance. You could still use forward scatter radio propagation over the horizon. That was fullblown out of Dana Bailey's head, and that was one of the prime means of communication during radio fade-out. It was used right after World War II, but it may have been used in the war, I'm not sure.

DeVorkin:

He was also National Bureau of Standards?

Roberts:

He was later, yes. At that time he was in the military. He was in the Joint Chiefs of Staff group at IRPL.

DeVorkin:

If I'm not able to contact Richard Silberstein, could you tell me just a little bit about him?

Roberts:

Well, I don't know him that well. I just know his name and I know him socially from cocktail parties and music and things of that sort, but I don't know his scientific work. But Alan Shapley would know it well.

DeVorkin:

You say Alan Shapley is in town?

Roberts:

Yes, they're all three in town, Dana and Shapley and Silberstein.

DeVorkin:

Well, talking then about your wartime work, this was primarily what you did.

Roberts:

Yes, and when I got the help, I wasn't under quite such stress to be here always, and went back East a few times and visited IRPL, and then immediately after — well, let me finish up. At the close of the war, Alan Shapley and I published a joint paper. Alan had been working at IRPL and I worked here. We published the result about the relationship of the corona and the ionosphere, I think, in the ASTROPHYSICAL JOURNAL, one of my early papers. But during that time, I think the most important discovery that I made was the discovery, or you might say the re-discovery of solar spicules. I assigned the name of "spicule" to them.

DeVorkin:

Yes, that's right. Let me just ask a few other questions about coronal activity and radio fade-out. It was classified. Did you find it difficult not sharing this information with colleagues whom you'd be in contact with at Harvard, or were you able to?

Roberts:

I was here all the time. I didn't get to go to Harvard much. But I would say no. You remember, that was a popular war and everybody was prepared to make sacrifices, and we felt, you know, it's tough. My brother was a Navy pilot in the war and was eventually killed. You didn't mind making a little sacrifice like that.

DeVorkin:

Yes. Would you say now that the war affected your career?

Roberts:

Oh yes, because I was planning to go back to Kodak, once the war was over. I forgot to mention that on one of my few trips I went to Dr. Mees to tell him I'd been frozen in my job. You know, he was great about it, and half of his research lab was in war work anyway, more than half I guess. So he said, "We'll just keep your job open, and whenever the war's over and you're free, come back, you've got a job."

So I was actually carried on the roster of Eastman Kodak until after the war, until October of 1946, and in September I went back and told Mees that I had decided to stay in astronomy, that I'd been offered a permanent post with the Harvard observatory, and so forth, and that we had incorporated the observatory. In April of '46 we incorporated it as the High Altitude Observatory, which by the way was a funny name. We wanted it to be the Climax Solar Observatory, but the Climax Molybdenum Company had Climax as their trademark, and so we had to get the permission of the company to use the word Climax in our name. So we said, "For incorporation purposes we'll just give it any old name." I said, "It's the highest observatory in the world, we'll call it the High Altitude Observatory and then we'll change it." We never changed it.

DeVorkin:

That's funny.

Roberts:

I said to Mees that I appreciated the help to go to graduate school and the fact that I'd been kept on the roster. By the way, they had supplied all the film for the observatory free and made it specially for us. Mees superintended the manufacture of a special film for the corona and for the prominences. I had the closest of relationships with the Kodak people, and I said, "You know, you've done all of this for me, for us, and I took the graduate fellowship with the expectation of coming back to Kodak, and now I'm not coming back to Kodak." He said, "if you do well in science, Kodak will be repaid."

DeVorkin:

He certainly had a nice view.

Roberts:

Then later I had the opportunity to know him in Hawaii, and played a role in the C.E.K. Mees Observatory on Maui. I was invited to give the dedicatory lecture, with Mees present, when the observatory was named the Mees observatory. Unfortunately I was not able to go to that meeting and I didn't give the lecture, but I've always taken pride in the fact that I was invited. I've visited that observatory with Mees.

DeVorkin:

Let's not talk about the establishment of the High Altitude Observatory, how it was actually done, the mechanics, until after we talk about your rediscovery of the spicules. Is that correct?

Roberts:

Yes. The reason I say rediscovery is that after I had discovered them — by the way, I discovered them one day by chance, really. I had always had a habit of scanning the edge of the sun to look for prominences after I'd done the routine coronal work. Then I would run a movie and let it run as long as the day remained clear. One particular day, there was nothing of importance to look at, and I had noted sort of casually that there appeared to be, in the polar regions, every now and then, some little spike-like structures.

DeVorkin:

In the polar regions?

Roberts:

In the polar regions of the sun there appeared to be some little tiny spike-like things, but I hadn't paid much attention to them. This day there was nothing important to photograph, so I decided to make a hand drawing of what I could see in the polar region. It's a thing that until much later we never were able to understand, but you can see things better than you can photograph them. The image flutters a little bit, and the eye takes the moment of good seeing and preserves the image and throws out the bad seeing. So you could make a drawing that had much more resolution than you could photograph. So I made a drawing, and spent quite a few minutes at it.

Then in making the drawing, I suddenly realized — I'd made the drawing from the left over towards the right — when I got over to the right, maybe five minutes later, the part over on the left was different from what I'd drawn. I suddenly realized that I was dealing with a short-lived phenomenon that was changing all the time, even though in general it looked identical, but the details were different. That was what led me to take the first film of spicules.

I took a one hour film of spicules, I think it was in March of '43. That was the discovery film from which I derived the lifetime and extrapolated the number of spicules to the whole sphere of the sun and so on. I call it rediscovery because years later, I found a drawing made by Angelo Secchi showing spicules.

DeVorkin:

Secchi, what would he have been using?

Roberts:

Well, he was using a spectrograph.

DeVorkin:

A spectrograph and wide slit?

Roberts:

Wide slit spectrum, yes. Then Harlow Shapley and I talked about it, and I told him how excited I was, and he said, "Well, you should give them a name. To be famous you have to have a name. Shapley said, "I suggest spicules." Little spikes. Then I used it in my first paper, discovery paper.

DeVorkin:

In that paper you noted that both Menzel and Mohler may have seen these things in eclipse photographs. Did they know what they were?

Roberts:

Well, Menzel always claimed that he did, but I don't know. Mohler I'm sure saw them but didn't realize that they had any significance. Secchi didn't realize any evolution either. They were static as far as he was concerned.

DeVorkin:

That's the important element that you added.

Roberts:

Yes, the lifetime and number.

DeVorkin:

Do you have what I'd call the discovery drawing?

Roberts:

I think it's in that paper. I think I reproduced the drawing in the paper.

DeVorkin:

Yes, but do you have the original, do you think?

Roberts:

I doubt it. I think I sent it off to the publisher and never got it back.

DeVorkin:

When you saw that these were such short-lived phenomena, what went through your mind as to their role?

Roberts:

Well, I got excited about them because we were looking for a mechanism to heat the corona, and I saw them as jets, high velocity jets. I realized immediately that to change that rapidly, they had to be supersonic, and therefore they were a source of possible heat, and Martin Schwarzschild had done some work on supersonic waves as a source of solar heat. We knew by then of course that the corona was hot. The issue was, where did the heat come from?

DeVorkin:

This was after Edlen, so you knew about Edlen's work? Or you just knew it was hot?

Roberts:

Now, wait a minute. No, this wasn't after Edlen, was it? This is '43. I forget when I published that paper. Maybe I took pictures in '43.

DeVorkin:

You took the pictures in '43. The paper came out ApJ 101, 1945.

Roberts:

By '45, then, we knew about the Edlen results.

DeVorkin:

Right, but I'm thinking of your first ideas, what was going on?

Roberts:

I don't think I realized anything except their striking frequency and their variability. I remember being quite thrilled by noticing that they were always there, and that they were always changing, and I don't think it was until Schwarzschild suggested the jet heating of the corona — the heating of the corona by jets of gas—that I developed the significance of the spicules.

DeVorkin:

Right. Had he known about your work?

Roberts:

I think so. We were very close friends and corresponded a lot, and I think I probably showed him the pictures of the drawings.

DeVorkin:

This was nothing that was considered classified?

Roberts:

No. It was only the corona relationship.

DeVorkin:

Did this have to go through a censor?

Roberts:

No. I was responsible myself. It's interesting that I set up a weather station there in order to have a front for the observatory. That's how I really got interested in meteorology. I had been interested in C.G. Abbott and the recurrence of droughts, but it was really through what I learned about it during the war by reading that I became interested in meteorology.

DeVorkin:

What was the reception of the importance of the spicules upon your publication?

Roberts:

Very very little. There was almost no recognition for ten years. Dick Thomas was excited about the spicules, but it wasn't until the invention of the solar wind that the spicules really became widely discussed and important.

DeVorkin:

Why is that?

Roberts:

Well, I guess in '45 they didn't seem like the solution to any important solar physical problem.

DeVorkin:

The heating of the corona or anything like that?

Roberts:

I wonder if I mentioned the heating of the corona in that '45 paper.

DeVorkin:

The only thing I recall from it is that you discussed it as a continuous outflow of matter.

Roberts:

I think I made a reference to the heating of the corona, but I'm not sure.

DeVorkin:

We can check that.

Roberts:

I've got the paper here... I think this paper was the most important paper that I did in those early years. Here is Secchi's "Observation of the vertical flames in polar regions."

DeVorkin:

It's surprising that Secchi would have been able to see anything that small.

Roberts:

Yes.

DeVorkin:

I have something marked there, on page 140.

Roberts:

Yes. "It is reasonable to hope that on a more detailed investigation, spicules may contribute to understanding the process of supply of material to the corona and regular prominences. Spicules are the only solar feature thus far discerned which seem observationally to indicate a continuous outflow of material through the chromosphere to the coronal regions. It may prove that spicules and somewhat similar small scale low latitude prominences are all there is to the chromosphere, and they actually the difference between the chromosphere and the prominences is, as Menzel suggests, one of degree."

Then I talked about the height of the chromosphere. I guess I didn't say anything about heating, only about the supply of material. So that must have come later, with Schwarzschild's paper. I found the number of spicules on the sun was much too small to be identified with granulation. So I knew they weren't granules. Yes, here's the old original drawing.

DeVorkin:

I see. That's on page 138.

Roberts:

Yes. That was a pen and pencil drawing. By the time I got over here toward the right, I looked back and saw that this didn't coincide with what I had drawn on the left.

DeVorkin:

Did that ever make you worry in the beginning that you were seeing something that wasn't real?

Roberts:

No. It was so clear. Then I started watching an individual spicule for a while, and I saw that it changed visibly in five minutes.

DeVorkin:

Did you have the ability to increase the magnification on your image?

Roberts:

Yes, but it didn't help, because the seeing was the limit. Fuzziness of the image.

DeVorkin:

When did the spicules become seen as the source of heat?

Roberts:

I would say, not until Eugene Parker and the solar wind, and Art Hundhausen and all those people. Later I got interested in the origin of magnetic storms, and came back to the solar wind and spicules.

DeVorkin:

We have about five minutes more on this tape, and I think this might be a good place to cut. But for the last few minutes, to finish up the war period, before we talk about the construction of the observatory or its formal establishment, I have a sort of a standard question I'd like to ask you. In the post World War II period, what were the major unresolved questions about the nature of the sun, and how were they attacked, and what did you feel was the best way to get at them? We've already talked about some of them, of course.

Roberts:

Well, I think the major unresolved question was the supply of energyto heat the corona. A secondary but also very important question, as far as I was concerned, was the nature of the force fields that governed prominence motions. The prominences obviously didn't fall according to gravity. They were falling in huge curved trajectories. We knew that they were somehow associated with magnetic fields, in the atmosphere of the sun, but the relationship of the coronal forms, which also represented, we thought, magnetic fields, and the prominence forms, which were so divergent, was not clear.

We were interested in how the motion of gases go on, how the gases transported in the atmosphere of the sun, and the differences between the prominences and the corona, why were they so different in their motion and behavior? At the same time, I would say, the most important problem on my mind was how the corona — and to a certain extent solar flares and certain kinds of prominences, what we call the yellow line prominences — how those affected the ionosphere. Was it X-rays? Was it solar "cosmic" rays? What was it that was disturbing the ionosphere in complex ways?

Already at that time, going back to my graduate school days, I had in the back of my mind, the big problem about the recurring droughts on the High Plains. Were they really related to the double sunspot cycle? How on earth could it be related to a double sunspot cycle rather than a single sunspot cycle? If it was radiation, it obviously couldn't be a double sunspot cycle. That implied it had to be magnetic field, because we know the reversal of the polarity of sunspots from one cycle to the next. I think those were, to my mind, the most important problems. I didn't get to work on the drought thing until almost eight years later.

DeVorkin:

You still had a lot of observatory building to do.

Roberts:

Yes.

DeVorkin:

To what degree was solar physics and this form of solar work an accepted central part of American astronomy? Did you feel like you were on the center or on the edge?

Roberts:

Well, there was very little solar physics in the U. S. at that time. I think we were pioneering and establishing, you might say, a demand, a constituency. The war had obviously shown the importance of solar physics to some practical things. Everybody visualized the growth of aviation and the need for communication. We didn't visualize the development of microwave that would eliminate the problems of solar activity and communications, but immediately after the war we realized that the radars that defended Britain couldn't be relied on, because they would be blanked by solar radio noise.

Kiepenheuer played a large part in that work also. So we knew that if we had another emergency, we might not luck out the way we did in this one, from the ionospheric standpoint. That meant that the Navy and the Air Force were both vitally interested in solar observatories. That's why after the war the Navy put up the money for the Climax postwar and the Air Force put it up for Sac Peak. Sac Peak started as a part of the High Altitude Observatory.

DeVorkin:

Yes, I'm well aware of that.

Roberts:

By the way, I made a big strong bid to inherit the Smithsonian Astrophysical Observatory.

DeVorkin:

When?

Roberts:

When Abbot was retired, but before Carmichael had decided to move it to Cambridge. Freddie Whipple and I were contesting for that.

DeVorkin:

Oh, really?

Roberts:

Yes. I wanted to move the Smithsonian Astrophysical Observatory here to Boulder, and it would be the High Altitude with its permanent name.

DeVorkin:

We've got to talk about that.... is this a convenient point to break?

Roberts:

Yes.

DeVorkin:

Okay, thank you.

Session I | Session II | Session III