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Oral History Transcript — Steven van Agt

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Interview with Steven van Agt
by David DeVorkin at
the National Academy of Sciences,
3 November 1977
open tab View abstract

Steven van Agt; 3 November 1977

ABSTRACT:A short interview centering on training at Leiden; recollections of teachers -- Oort, van de Hulst, Osterhoff; growth of Dutch radio astronomy; present state of astronomy in Holland.

Transcript

DeVorkin:

Could you give me a little information on your early home life and some of the influences upon you that brought you into astronomy? First, your birth date and where you were born.

van Agt:

I was born in The Hague, April 28th, 1931. What brought me into astronomy? As a matter of fact, when I finished high school, I really did not know what to do, what kind of study to take up. That was a time when you still had various possibilities, you could look for what you would like to do, and you could get in when you liked to do it. So, I did not even start in physics, but I started in law. I did it for a year. Then I had to go to military service. I tried to do some examinations when I was in military service, and I think I just found out that I didn't like law at all. So when I came out., after a year, that was the time when it was still a very short military service -- (these days it is two years) -- I started in 1950. 1 came out of the service in '51 and I started school again in the end of '51. Then I decided, I liked to do physics, so I did. And rather gradually, by getting into contact in the introductory course, which was given by Professor Oosterhoff at the time, I started to like astronomy and so I rather gradually changed over frcm physics to astronomy.

DeVorkin:

What was it in his lectures?

van Agt:

Well, I think the enthusiasm, the personal note, the small group, the kind of work, and also because there was so much -- well, what we got in that introductory course was, of course, the first results from post-war astronomy, which was the radio hydrogen line, the galaxy, the spirals and all that sort of thing.

DeVorkin:

You're talking about radio astronomy at that time?

van Agt:

This was radio astronomy, yes. But also the connections that there were between optical astronomy and radio astronomy. At that time Leiden still was rather astrophysical, with radio astronomy coming up very strongly, and it was a very special atmosphere in those days. New results came out. People were working at it. Well, I think it attracted me.

DeVorkin:

Your education though before that?

van Agt:

Let me say what kind of family I came from. My father was a teacher in physics, mathematics and biology in a high school.

DeVorkin:

This was in The Hague?

van Agt:

That was in The Hague. Well, I come from a fairly large family, and we all went to high school, and I think we learned to be interested in what happened around us.

DeVorkin:

There's a planetarium in The Hague?

van Agt:

There is a planetarium in The Hague. As a matter of fact, I never went there before. I know there are people who say that they went into astronomy because they went there when they were six or seven, and after that they had taken their decision. I'm not so.

DeVorkin:

So you had no developing interest in astronomy?

van Agt:

No. I think my interest in astronomy was rather personal and emotional, because I remember that once before, this was still my high school period, I lived close to the North Sea, and our house was the last house in the city and then you had the dunes. You walked in the evening in the dunes, and you saw at that time still sky. There was not so much pollution. I got interested in that, to look at it, and I made a map, just by sitting there and having a piece of paper, and a flashlight and I looked up and I just plotted the stars and made a nice star map. I think that was the only thing I really did that was astronomy.

DeVorkin:

This was on your own?

van Agt:

This was on my own, entirely on my own, yes.

DeVorkin:

Did you find the names out from a book or something?

van Agt:

Yes. I had an old book I found at that time in my father' library about the stars and I checked it out

DeVorkin:

Do you recall the book?

van Agt:

I think it was German -- I can't remember the name -- a kind of pocketbook edition series with all sorts of subjects in physics.

DeVorkin:

What was your age about that time?

van Agt:

I think I would have been 16, 17.

DeVorkin:

OK. Had you considered physics seriously from your father's influence?

van Agt:

I think I considered it seriously from my father's influence. But then, I had also considered, just because there was the father's influence, not to do it. Maybe that made me take the decision to go first to law school, and then after that only to realize that I liked physics better than law.

DeVorkin:

Right. With your father being a teacher, was your mother also college educated?

van Agt:

My mother was a teacher in French. What her education in that respect was, I don't know really.

DeVorkin:

What was the regard for education in your family? Obviously it must have been pretty high.

van Agt:

Oh, tremendously. I mean, you could not speak about not going to a university. It was the natural thing to do.

DeVorkin:

From your knowledge of the conditions let's say during the war, and social conditions in general just after the war, was it also considered that there was no alternative to university amongst the people that you frequented?

van Agt:

I think so. Yes. It was still the normal thing to do. At this time it would be much more normal to consider what somebody really likes to do and university education is not looked upon as the best and only possibility, I think, these days. There are more alternatives. But at that time, I don't think there was really an alternative unless you really wanted it. Then you had to fight for it

DeVorkin:

Fight for a non-university choice?

van Agt:

For a non-university education. Right.

DeVorkin:

Very interesting. OK, when you did get exposed to astronomy by Oosterhoff, I guess he was your first teacher -- what were some of the topics? You mentioned, of course, the work right there at Leiden. When you achieved a level where you began participating in research, or thought you could participate in research, what did you look at? What did you find most interesting?

van Agt:

The practice in Leiden was that the first three years of the university teaching, it was the curriculum. There was a one-year introductory course, and that was the thing you got in the first year. And then, if you then decided to go on with astronomy as the major course for your Candidat's exam, there were two other additional lec¬tures, I think. One of them was by J.H. Oort and the other one was by H. van de Hulst, if I remember correctly. I might be wrong. Oosterhoff, of course, at that time, was rather classical -- ¬very enthusiastic. A big part of the time was given to planetary motions and everything with respect to that. And as a matter of fact, galactic astronomy came last. It was the traditional build-up. It was given as sort of a delicious course at the end of the year. In addition to the lectures, Oosterhoff also had a lab course, which was generally a rather small group, say about ten stu¬dents. And there he had all these little lab courses where you got a more personal approach from him to you, because he helped you. That, I think, was extremely stimulating, because the things were really built in the sense that you got a feeling for what was going on, that you got a result, you see, that you were interested in actual measures, and that always had to be a principle there.

DeVorkin:

Was there observing?

van Agt:

There was no observing. It was the actual measures. It was a daylight course. But you got the measures on a sheet, and you were told how they were produced.

DeVorkin:

So through the semester you would start with the data to analyze orbits possibly?

van Agt:

For instance, yes.

DeVorkin:

Then you'd go from there.

van Agt:

Yes. And later, I think, in the third year or so, you got to observe. There was the "light collector." This is a particular telescope.

DeVorkin:

Why is it called a light collector?

van Agt:

Because it is not an imaging thing. It makes an image, but you could only use it photoelectrically.

DeVorkin:

So that must have been a rather recent instrument?

van Agt:

No, it was quite old. It also had another name, the "Zunderman," it was called. I think he was the mechanic, the head of the office of mechanics at the technical department who built it. It was not a particularly good instrument, but it worked well. Then, there was a ten inch telescope on the roof which was extremely old, with a German mounting, and there was the double refractor, which is still there. Well, those were the telescopes, and some little things, like a comet telescope.

DeVorkin:

But you didn't touch these until your third year?

van Agt:

No. No.

DeVorkin:

Let's continue with your courses, then. When did Oosterhoff indicate what his research was, and start talking about his own re¬search? Was that in the first year?

van Agt:

No. There was nothing as I remember in the first year, no. His own research did not come in explicitly. That came only in a later phase. I think he kept it rather quiet. He published his re¬sults, but there was not a real chorus about what he was doing.

DeVorkin:

Did you read any JOURNAL articles in the first year?

van Agt:

Oh, what you read there in the BAN.

DeVorkin:

So you did read the BAN your first year.

van Agt:

Definitely, yes.

DeVorkin:

As far as texts are concerned, what did you read, as far as standard texts go?

van Agt:

Standard texts, oh, there was Smart.* And there was Russell Dugan and Stewart,** of course, which we see here on exhibit -- you would walk about it, you would say. "Ah, yah, of course." Oh yes, I haven't had it in my hands for a long time now but you'd just remember the first page. Yes. Russell, Dugan and Stewart. I think those are the main things. There must have been more that I don't remember now. *Spherical Astronomy. **Astronomy (Ginn, 1927)

DeVorkin:

You did then have access to the journals, you were aware of them.

van Agt:

Oh yes. Yes. Also it was explained to you that the library was open for your use day and night, you could go in, you could take books out, and you got the BAN. You got the BAN as soon as you got your Candidat's exam. You just got on the list.

DeVorkin:

I'm still trying to straighten it out chronologically: you took your Candidat's, then you went for your three years for the Doctorandus.

van Agt:

Yes, that's right.

DeVorkin:

So what year did you get your Candidat's?

van Agt:

That was in, I guess, '54, '55.

DeVorkin:

So at that point you started taking astronomy?

van Agt:

At that point I started really taking astronomy, and only astronomy almost. There were some other physics courses you also had to follow, like quantum mechanics. It was just a lecture course. It did not include practical work, or only very little, in physics. It was almost full time astronomy.

DeVorkin:

Right. So your first course in '54-'55 was with Oosterhoff?

van Agt:

The first course was the introductory course with Oosterhoff -- that was before my Candidat's. And then, after you had your Candidat's, you get the serious courses, that was Oort, van de Hulst and Oosterhoff again. Oosterhoff I think gave a course in photometry and what you could do with that, and a lot of technical things. And van de Hulst was astrophysics, stellar atmospheres, radio astronomy. And Oort, gave galactic dynamics. And that was, of course, the full story. In addition, there was another course with Oort, I think. Yes, there was a full course one year about the results of distribution in globular clusters, and the comet clouds, you know, this interlaced -¬- the same sort of techniques he uses in his velocity distribution in globular clusters, you find that in his theory about the cloud of comets. That, I have always found fantastic, the way Oort gave his lectures. There are a few things one should remember. He is a very deft talker. He usually was looking at the blackboard and writing things down. He never looked, or hardly, to the audience, so it didn't help the clearness of his voice, and then he spoke very softly, so you had to sit in the front row, which was not always possible. You really had to listen. And then, it was very difficult during the course to find any line in it. It looked to be very broken up, but then, when you really got to start working in the course, and it was finished and you had to do your exam in it and so on, it was really one of the most beautifully built up courses. Oort's lectures were really stimu¬lating. There you really got the feeling: "I'm at the border of what is possible now to know." As a matter of fact, it's still so. When you meet Oort these days, he is fantastically active. If you give him a new clue, or if it's something he does not know how to place, and if it is necessary to throw other things away, he's fully capable and willing to do that. He's still the revolutionary, in that respect. But also, I always had a feeling, the way he talks and does lectures and colloquia, that he is very strongly intuitive, that intuition led by a fantastic amount of factual knowledge. He knows that if you have theory that might look nice, but then there is some far away part or some other observation that does not fit in that new theory, so the new theory is not a valid one. He's just marvelous. It was just great to have studied so near to Oosterhoff, Oort, and also from van de Hulst. I think there are new people now who have the same sort of thing. But Leiden was just fantastic.

DeVorkin:

What of the others -- van de Hulst and Oosterhoff? You indicated that your first contact with him was quite stimulating. Did this continue?

van Agt:

When I got my Candidat's, I started to work with him, and there I did globular clusters, variable stars, period determinations and all that, and I think it was stimulating, but not so much the frontier work which you saw going around, right?

DeVorkin:

But in those years, just those years, if he was doing globulars, was he doing stellar evolution at that time? Or was he talking about stellar evolution?

van Agt:

He was talking about stellar evolution, yes. I think he was himself strongly busy with the photometric part of it, being very careful in that. He also had the responsibility for the Southern Station in South Africa, where, of course, mostly photometric observa¬tions were done. And in that respect, he was extremely careful and critical, and I think I learned the trade there really well.

DeVorkin:

Was he talking about color systems, developing and using them?

van Agt:

Yes. Yes. The real color systems came really a bit later

DeVorkin:

It was just in the beginning, that's true. But at that time, of course, people were aware of these things, and Sandage was doing a tremendous amount of work in clusters.

van Agt:

Oh yes. Yes.

DeVorkin:

What did Oosterhoff seem to think was going to be the future? Did he confide in his students what the future might be in this kind of work? How did he encourage work in photometric systems?

van Agt:

I think he talked about it. Now, I remember he talked for instance, quite extensively about Chalonge's work and that sort of thing.

DeVorkin:

OK. That would be, in terms of what systems he was most interested in. What kinds of indices was he trying to isolate, or that he thought might be important.

van Agt:

Well, that I cannot say.

DeVorkin:

OK. Van de Hulst, what were his courses like?

van Agt:

Van de Hulst was giving the course in stellar atmospheres, and in radio astronomy. There were two courses. Stellar atmospheres he did perfectly well. He was also again extremely careful in find¬ing the basic relations, not just giving them, but showing how you got them. He was, I think, not so interested in the end result, but in showing how you got to those results. For the observing results, but also for the formulae you have to use like transport equations and dynamic equilibrium and all that sort of thing. And the book we used there was -- could it be Aller?*

DeVorkin:

I'm not sure of the dates of his earliest books.

van Agt:

I think it was probably Aller. But also, there he was very critical, because he did not use all the chapters.

DeVorkin:

Aller, of course, started with LTE. Was there any question in van de Hulst's mind that this was valid, or not valid? Did he criticize it?

van Agt:

He thought it was perfectly all right.

DeVorkin:

The radio astronomy course -- I'm very interested to know if he reviewed in detail how he arrived at the 21 centimeter? *The Atmospheres of the Sun and Stars (Ronald, 1953).

van Agt:

Oh yes. Yes. That he did, very carefully, and he showed how to figure it out, and I think he went into it rather basically. All the distributions you could get, that you could really calculate, that it should be possible to observe certain lines -- etc. And he definitely gave part of his course in the sense that he discussed the 21 centimeter line at that time.

DeVorkin:

Did he ever say why he was looking for it, or why he was interested in it?

van Agt:

There was something of an encounter between van de Hulst and Oort during the war. And I think the story was that during the war, van de Hulst calculated it out.

DeVorkin:

Well, he did make the calculation during the German occupation.

van Agt:

That's what I think. Yes.

DeVorkin:

Had he revealed to you, to the class, the process by which he became interested in the problem, this is what I'm very interested in?

van Agt:

I'll try to remember. There's something vague. Oort might have said, there should be a lot of loose hydrogen. And van de Hulst took it up, maybe stimulated by the question from Oort's side, where you could possibly find the lines, and then van de Hulst tries to look if -- recalculating, there was a line.

DeVorkin:

So it could have possibly been a suggestion by Oort.

van Agt:

I think so. Yes. I have that feeling that it is, that I heard that once.

DeVorkin:

Fine, we'll put that down as conjecture. Did Oort ever talk about his teacher, Kapteyn?

van Agt:

Not so strongly, no. Connections with Oort in that period were mostly through the lectures. And in the lectures, he kept him¬self very strongly to the subject. But what was, for instance, happening with Oort's lectures, was that he gave a lecture on Thurs¬day morning, and the next Thursday morning, he would re-quote parts of it, because in the meantime he had figured out new figures, so we had to correct it again, and that sort of thing.

DeVorkin:

His lectures were spontaneous and then he'd go back and correct them, is that it?

van Agt:

His lectures were part of his research.

DeVorkin:

I see.

van Agt:

A big part, I would say. Not in the beginning, of course, but when it went on and got more specialized. It was just part of his research. It was not giving standard data, etc. etc. He was working with it.

DeVorkin:

During any of these courses at this time, did you start looking for research problems? Or were they always directed to you?

van Agt:

They were directed, at that time.

DeVorkin:

All three of them directed research problems?

van Agt:

All three directed research problems. I was working most directly with Oosterhoff at that time.

DeVorkin:

Was this a choice of yours?

van Agt:

No, it was not so much a choice of myself. It was rather, how do you say it, autocratic at the time, still. I mean, the stu¬dent did not have so much to say. Things were decided, and you could not really go against it. Also, one should be happy that one could get a place at the observatory. I mean, you had no rights. You got involved, but people were telling you what to do.

DeVorkin:

That's a very important point that you bring up. Now, after the Candidat's, was it predetermined that you would go on to the doctorandus? I am thinking in terms of both career choices and choices of graduate education, if we can call it that. Could you have gone elsewhere for your doctorate?

van Agt:

It was not a normal thing to do in Holland.

DeVorkin:

So you stayed?

van Agt:

I stayed. Yes.

DeVorkin:

At what point did you start thinking in terms of your career, being an astronomer?

van Agt:

Well, I think one year after the Candidat's. Well, let's say it like this: at that time, it was not normal that you could get a position. And positions that were available did not pay very well. So it was still a question: "Will there be a place or not, when I'm finished?" So one always had in mind: "I could do this, I could also go to teaching, which is also beautiful to do, of course."

DeVorkin:

This is highly regarded in Holland, a teaching position?

van Agt:

At that time, yes. Then there came a period that it was quite easy to get a position at the University. Now we have again a period that it is extremely difficult to get a position anywhere. Maybe it is not that bad, I would say. To come back to this career of mine at the University, I would say it was rather planned, by other people than by myself. Well, you had your preferences. You could show them. But also, astrophysics, as it was done then, had its nice aspects. Radio astronomy had its nice aspects. And there was still this double line. At the moment I think, in Leiden and in Holland as a whole, radio astronomy is the thing to do. At least, it has been for a long time. And only now, people start to realize that optical as¬tronomy is just another part of the spectrum, and that one cannot really do optical or radio alone -- that it would not be wise to just let go of the experience, the traditions, the connections you have in optical astronomy, in a modern way. So, people are trying to stress that a little bit, and to help optical astronomy a little bit further. I think it has been lagging a little bit, in the last ten years.

DeVorkin:

I see, in Holland?

van Agt:

In Holland, yes.

DeVorkin:

That's interesting.

DeVorkin:

We were talking about the feeling, I guess it's a national feeling, that there has been a bit of a lag in optical astronomy, because of the tremendous impetus in radio astronomy in Holland. But the first question, of course, that would come to mind immediately was, why do you suppose it was Holland that led the world in radio astronomy after World War II? How would you point the finger?

van Agt:

I think it was Oort definitely.

DeVorkin:

Why do you think that?

van Agt:

Well, I think, because he had, as I've said before, the intuition, where the interesting things were and what had to be done.

DeVorkin:

This was his intuition.

van Agt:

I think it was intuition, led by his fantastic knowledge of what was going on. I think Oort has a very strong feeling: he wants to further astronomy. He really wants to push out the borders further away; to really answer the basic questions you can put yourself. I think Oort is magnificent in asking basic ques¬tions. And to say: 'Well, this is at this moment the important thing. That, we have to know, if we don't know it, we can't go further." He is able to stick to that question, to keep it in mind, to work at it. He has enormous pushing power. And he has a fan¬tastic amount of relations. In addition, he is one of the most kind people I ever knew. He is very humane, and I think it is a combina¬tion which you won't find very often. But I think, indeed, the pushing power has been Oort's, and he has been the big leader in Holland, in that respect.

DeVorkin:

When you mentioned the lab that you had, it seemed to deal with mainly optical astronomy?

van Agt:

The lab courses, yes.

DeVorkin:

When did you first encounter any kind of labs in radio astronomy? Did they have any?

van Agt:

No.

DeVorkin:

When did you first encounter radio astronomy? Only in lectures?

van Agt:

Of course, there was a lot of radio astronomy going on, at Leiden, so you'd meet the people. They'd talk about it. There was at Leiden a very well organized colloquium committee. We had one per week, Thursday afternoon, always, called the Literature Club, where everybody had to give a review of recent literature, and most students were involved in that, also the staff people You got ten minutes, fifteen minutes, five minutes, depending on the article, and then the next week there was a colloquium, where one person had the whole afternoon to give a real in-depth talk about, either what he did himself, or about a very important paper. And there, certainly, radio astronomy was presented very often, and I think that must have been the first introduction. Then, the way it was presented, it was of course fascinating because everything there was new; new results came out all the time.

DeVorkin:

What about the techniques of radio astronomy? Did they leave them to only the practitioners? This was not something to be learned in a course?

van Agt:

The course came later, after several years, when the first results really were available. I think people sort of rounded up their knowledge in a lecture course. In a lecture course, I remember also, a number of BAN articles were reviewed and used as the basic material for the course itself. Like, for instance, how to reduce an observed curve, and get the instrumental effects out of it, and all that sort of thing.

DeVorkin:

Yes, these are the important aspects, of reduction of observations. Now, when it came to building, designing and generating radio telescope equipment, was this thought to be something within the astronomer's realm, or not?

van Agt:

Oh yes, definitely, in the sense that van de Hulst had the opinion that if you were working with the radio telescope, you should know, in an elementary way at least, what's going on in the black box. They did not believe in the black box where you put in radiation on one side and you get a publication on the other side. No, no, no, not that way.

DeVorkin:

That's a marvelous statement. I like that. Is that original to you?

van Agt:

I think I found it out just now.

DeVorkin:

Just now?

van Agt:

I visualized it in the most simple form I could possibly. I don't know. Well, so, we got this rather extensive training. For instance, the very basic principle of signal to noise ratio, which was rather extensively treated by van de Hulst. Where does the noise come in and how can you reduce it, and where is it important and all that. That was definitely discussed. I think we also made a rather extensive excursion to the workshop where they make all these things. A few instructive demon¬strations showing the very simple thing, that when you have a dipole as an antenna, you only get half the radiation. I mean, you can show it with a simple setup, and that was done.

DeVorkin:

This shop was at the observatory?

van Agt:

That was at the observatory, that's right. And then, I think, before the Candidat's, yes, when I was a student, there was the radio telescope, the first one we had, that was not Dwingeloo, but before that, Kootwyk. The first measures were taken with an old German radar and that was at Kootwyk, on the grounds of Radio Holland. At that time, there was a very strong cooperation with the Dutch postal service. They were in that same work. The Dutch postal service also had a department of solar survey. At that time, you know, we still were a kingdom where the sun never set. We had of course Holland. We had a station in South America, in Surinam, and in New Guinea, so we had through the day, the 24 hour possibility of checking the sun, and that was the work of the M (Post Telegraph Telephone). That was of course important, for they had -- that was the excuse for them to do it -- to know what influence the sun had on international radio communications. That is not in existence any more.

DeVorkin:

So you were taken on. You were shown the "nuts and bolts," so to speak, of the radio installations, getting back to radio.

van Agt:

Yes.

DeVorkin:

And you were given an appreciation for every stage in the development of radio astronomy.

van Agt:

Yes, that's right.

DeVorkin:

That was the philosophy.

van Agt:

That was the philosophy, and I think it is right. If you really want to work with things, then either you should work with the proper telescope or you should have a very realistic setup which shows you how it works. I remember also that I was, as a student, involved in those measures, because there was a 24 hour measuring project going on: it was the distribution of the hydrogen in the plane, and from this they found the spiral arms -- that was done, in the first place, with this old German radar thing, in Kootwyk, and it was a hand moved thing. I remember that you would sit in there, in a sort of cabin behind it, and that you had to move the telescope every two minutes for eight hours, move it a particular distance, and then you could sit down and check on the data.

DeVorkin:

You were part of these observations?

van Agt:

Yes. Yes. Everybody was, from time to time.

DeVorkin:

Were you paid for this?

van Agt:

Yes, you were paid for that, quite well, I think, for that time. You could stay in a hotel nearby, but it was hard work. I mean, to keep awake for eight hours, doing that sort of gymnastics exactly every two minutes. It was very primitive. You had to start a motor, with a real staff, and if you moved your hands wrong, you got a tremendous shock, and it was fantastic. It was really primitive.

DeVorkin:

And who was the organizer of the whole project?

van Agt:

That was Oort, I think. Yes. Gart Westerhout was involved at that time very strongly, so he was in it too, to organize it. But I remember that I had to come to Oort. Oort asked me, and set a time that I would go there, and he explained to me what it was all about.

DeVorkin:

What was your support, other than that, during the time you were a student here -- your financial support?

van Agt:

My financial support? Oh, it was quite a nice trick. I was paid by my father.

DeVorkin:

You were paid by your father?

van Agt:

He gave me the money to study. Right? But I was supposed to pay it back, later, and with that money, my younger brother would study. But it was really nice of him. There were five boys and they all studied. The first one started that way, and the money he paid back, the next one could study, and then the third one, so we all made out with our studies really with the same money.

DeVorkin:

You were the oldest?

van Agt:

No, there is one younger son, how do you say it, there are five boys and two girls, and so I was the fourth boy. I am the fourth boy.

DeVorkin:

Was education quite expensive in terms of being a certain fraction of your father's salary?

van Agt:

I think it was quite expensive, yes. For that time, yes.

DeVorkin:

So not everyone went on to the Doctorandus after the Candidats.

van Agt:

Oh, they all were finished, yes.

DeVorkin:

Everyone in your family too?

van Agt:

Yes.

DeVorkin:

What were some of the other disciplines that they went into?

van Agt:

My oldest brother was in Indonesian goverment. It's a sort of university course to become an administrative officer in Indonesia. But of course that's changed, so now he is in foreign service, and at present he is Dutch ambassador in Moscow. OK, now the second did art history, and he is at the office of protection of monuments. The third one did law. The fourth one, that's me, astronomy. And the fifth one is finished in physics and is head of a department in the technical high school in Delft.

DeVorkin:

That's quite a remarkable spread in occupation.

van Agt:

Yes, right. But then, of course, if I have to say some¬thing about myself, I'm an astronomer at the moment, but also I am a sculptor. That's what I do as a line next to it, and I take for both things the time I need.

DeVorkin:

What about your normal financial needs? How are they satisfied, through astronomy?

van Agt:

At the moment, yes. I have an extremely good position at the university.

DeVorkin:

So professionally then, in terms of being financially supported, you are an astronomer.

van Agt:

Yes. Financially supported, I am an astronomer.

DeVorkin:

Right. OK. But you have very strong outside interests.

van Agt:

Yes.

DeVorkin:

Marvelous, OK. Well, that's a digression from what we were talking about before, but it's important to understand these things better. You were talking about the project that you were employed on, the mapping, the spiral structure of the galaxy, and you said that just about everyone in the observatory at one time or another did the supervising of this.

van Agt:

Yes

DeVorkin:

At this time, of course, there must have also been a lot of interest in the growth of radio astronomy and better telescopes, more sophisticated telescopes, and also the need for more manpower.

van Agt:

Yes.

DeVorkin:

Especially in radio astronomy. What were the pressures upon you to go into radio astronomy?

van Agt:

I don't think there was any pressure on me.

DeVorkin:

But this autocratic style that you said pretty much dictated who you worked for and what you did?

van Agt:

Well, when there was a decision taken, that you were not going into radio astronomy, then there was no pressure any more.

DeVorkin:

Well, when was that decision made? You're in optical astronomy.

van Agt:

I was in optical astronomy. And when you are doing it -¬- you know, you start working, you start to like it, so why change?

DeVorkin:

OK. So your first problems were given to you. What were they?

van Agt:

The first problem, just find variables and periods of variables, just blinking and finding the periods. At that time, it was still hard work. There were no computers. And what computers there were were little, and were those Marchant machines, which you had to flip over with your hand, and not the quickest way of getting the results.

DeVorkin:

Right.

van Agt:

But at that time there was an old Schilt photometer, which is the fixed diaphragm type, which therefore is only useful for a limited range of magnitudes. And in that period, Leiden got a new Sartorius type diaphragm iris photometer. And that was, of course, a big thing, and we used that.

DeVorkin:

Have you been in variable star research since then?

van Agt:

Since then, I've been in variable star research. I stayed in.

DeVorkin:

That, of course, was Hertzsprung's interest.

van Agt:

That was also the tradition, of course. It was also the tradition.

DeVorkin:

When you started working, did it bring you contact with any of the memories of Hertzsprung? Of course, Hertzsprung was still around, wasn't he?

van Agt:

No. Hertzsprung was, when I came, not around. But I remember one story by Oosterhoff about Hertzsprung. There was a sort of room. This is in Sterrewacht Lane. And when you came up, to the house, there was the astrophysics building, and he was sitting there. (Sterrewacht Lane was on a separate compound -- the observatory lane.) And from his place, he could overlook the whole lane, so everybody who came up saw Hertzsprung, and Hertzsprung saw him. But it was a sort of feeling you got, like "there is the Godfather sitting and I'd better be careful." Oosterhoff had this room next to that, at the time of Hertzsprung. And he was working on plates. Then he dropped one plate, and it went to pieces. That is, of course, a terrible thing, because in the atmosphere of that time, a plate was a lot of work and a lot of expense and irreplaceable, and it was the biggest sin you could do, was break a plate. So Oosterhoff was very anxious, and did not really know what to do. And then he said., "I have to tell Hertzsprung, of course, because he will find out. I have to tell him." A dilemma. So then he considered by himself: "How am I going to tell him? What will happen if I go in and I say, 'I broke a plate.' Hell and disaster!" So he said to himself, 'Well, I am going to tell him what will Hertzsprung ask me when I come in and I say I broke a plate?" Well, he just decided that the only thing Hertzsprung would ask is, "How many pieces?" So he counted the pieces. And there were thirteen. So he went in and Hertzsprung said to him, after he told him "I broke a plate." -- he was silent for a while, and he said, "How many pieces?" Oosterhoff said immediately, "Thirteen." Then OK, go ahead. It was solved. He was probably stupefied by the quick answer, but also it showed the mind of Hertzsprung, in a way, because his concern was not really: "The plate is broken, but, can you still go on working with it? If you know how many pieces there are, then the plate is not lost."

DeVorkin:

Marvelous. Well., where was Hertzsprung in the late fifties? He was traveling around?

van Agt:

I think he was in Denmark. He went back, that's right.

DeVorkin:

OK, I'm not that familiar with his later life. You never actually saw him?

van Agt:

I saw him at an IAU meeting in Hamburg, I think. Yes, I think he was there.

DeVorkin:

OK, well, we're up to the point where you were to choose a thesis, I imagine, for the Doctorandus.

van Agt:

I was very lucky at that time. Before I got my Doctorandus, it was common that as soon as you had your Candidats, you were involved in scientific work.

DeVorkin:

Yes.

van Agt:

And everything you did was meant to be published. So immediately you started really to do scientific work, with the aim of publishing it. It was not a pastime or just training, it was the real thing, and that's still the way they do it. So when I published my first globular clusters, then I got plates from Baade's heritage. I got plates on the Ursa Minor System, that he took with the 200 inch. And so I started work on that, and that became my thesis.

DeVorkin:

These are variables?

van Agt:

The Ursa Minor dwarf galaxy -- that was variables. I had to find the variables.

DeVorkin:

I see, OK.

van Agt:

Again, now, it was quite beautiful materials.

DeVorkin:

OK. And basically, the data were presented to you.

van Agt:

Well, the plates were presented to me, but that was the way it went in Leiden. There was a Southern Station, where people went observing, but it was generally the older staff members who went there, sometimes the students. They came back with programs obtained and plates, and they were given out to the students. So this was the way the whole thing went, at that time.

DeVorkin:

You hadn't done any observing at that time?

van Agt:

Well, I had done some observing at Leiden, but that was only good training, because it was a terrible site. You did get in¬volved in all the problems you can get when you are observing.

DeVorkin:

Well, what is the process of actually getting your Doctorandus? You submit your thesis, then you have to defend it, is that correct?

van Agt:

Yes.

DeVorkin:

And what was the nature of the defense? How was it or¬ganized?

van Agt:

You write your thesis. You discuss it with your pro¬moter.

DeVorkin:

And this was Oosterhoff?

van Agt:

That was Oosterhoff. Then you give it out, and or¬ganize the promotion. Then you are interviewed by professors in astronomy, from the country and from Leiden, from the difficult aspects they find they'd like to ask a question about.

DeVorkin:

Anyone can ask questions, or are these invited professors?

van Agt:

Anyone who is on the other side of the table can ask ques¬tions if he likes.

DeVorkin:

Is it open to any professor who wishes to come in?

van Agt:

It is open, I think, to all professors of the faculty, but they divide it a little bit, and the people who are interested in you or have known you, they come, and they ask questions. It is quite serious, but it is also rather friendly. I mean, nobody who gets in will not get his promotion. But they can make it rather hot for you if they like. I remember one thing about the promotion. Van de Hulst asked me something about a diagram somewhere, "It's stated here, and there and there, but I cannot find it." And I just, by some chance, knew that it was on page so and so, so I could give him an immediate answer, and I think he was a bit stupefied, because he didn't ask me anything further.

DeVorkin:

So he asked you where a diagram was?

van Agt:

Maybe he had wanted to go on and do a question about the diagram, but the answer, where it was, was so quick, that I think he just forgot to go on.

DeVorkin:

Well, that's the same sort of thing, with the plate, ask¬ing how many pieces.

van Agt:

Yes. If you are quick, it just came out rather automatical¬ly, "If you want to find it ... "

DeVorkin:

How did you become placed in a university? Did you go di¬rectly to a university after your Doctorandus or did you stay in Leiden?

van Agt:

I stayed at Leiden for some time, I think, a year or so.

DeVorkin:

Was this the normal thing for a new Doctorandus?

van Agt:

If they had a place and they liked you, you got a place.

DeVorkin:

But there was no trouble with staying around.

van Agt:

No, there was no trouble.

DeVorkin:

What kind of support did you have during that year?

van Agt:

By that time, I was an assistant, and I was paid by the Observatory. Then I think I was already one year after my Candidats an assistant to the Observatory.

DeVorkin:

How did you become placed after that?

van Agt:

I think I then got an offer from Nijmegen University, which started a new department, and I consented to do that. At that time, there were two options, really. There was an alternative. I also could get a place with Elsevier Publishing, in their scientific de¬partment, and I remember that I considered that very seriously, but in the end I liked better to go to the university atmosphere, and not leaving it. I did not really like the business atmosphere. And how did I get that alternative? Because, since the first satel¬lite, the first Sputnik went up, I had started writing weekly articles in the daily newspaper, which was a country-wide newspaper, not in existence any more, and I liked it. And so I got sort of connected in half ways with the publishing atmosphere and people, and they ask you questions, whether you would like to do more? They are always glad to have somebody who was doing it. And it was the "in-thing" to write about at that time. Again, it was new. Well, fantastic -¬- a thing that went around the earth -- well, "on to the moon," and that sort of thing.

DeVorkin:

People were really excited in Holland with Sputnik.

van Agt:

Yes. But I think I wrote more about astronomy than about space, at that time.

DeVorkin:

Have you been at Nijmegen University ever since?

van Agt:

I've been there ever since, yes

DeVorkin:

So that was approximately 1958-59?

van Agt:

1960

DeVorkin:

OK. What is the funding for this particular university?

van Agt:

It was in origin a Catholic university, which was paid by funds they collected. At the time I went there, it was, I think, 95% subsidized by the government, and now it is 100 per cent goverment paid. It still has its name, but it doesn't really mean very much. It's one of the most Marxist universities in the country.

DeVorkin:

Was astronomy established there when you went?

van Agt:

Not really. No.

DeVorkin:

Was there great growth in centers studying astronomy at that time, with Sputnik and the growth of space work?

van Agt:

There was quite some interest. Yes. But that has gradu¬ally gone down, not because the interest in -- well, I think it has to do with the general reaction of young people towards the physical sciences and the technology, that they got a little bit fed up with it, and that they asked themselves the proper question, "What is it all going to lead us to?" So, the problem now is, I think, double: that they don't go easily in the physics direction, because there are no job posi¬tions, but still, also, because they feel there is more than only physics, and so they are more interested in sociology, political science, psychology, or just growing potatoes.

DeVorkin:

Well, OK. What is the department like? Do you have a de¬partment in astronomy?

van Agt:

We have a department in astronomy, which is not a very good department of astronomy, I think.

van Agt:

I think one aspect I always have liked in astronomy, that is the close cooperation between all the institutes. It was, what one could say, a very friendly atmosphere, critical to one's work, but it was always possible to go from one institute to another as a visitor. In the end you get to know the people really well. Once a year in Holland we have the Dutch Intra-Academic meeting lasting a few days, which always had a very special flavor. It was meant for students and staff to get to know each other. It always started with a football match or something, a ping pong contest, and an eve¬ning where everybody did something, like a play or music. At Leiden I remember people were very enthusiastic really to start things, to prepare things, to do funny things. I think it just stresses the point, how good the cooperation was, also in the humane sector -- not only in the astronomical sector, but also for meeting each other just as friends. And I think that has gone; that feeling you do not find in any astronomical depart¬ment in Holland.

DeVorkin:

Why?

van Agt:

Why? I don't know.

DeVorkin:

It's a very important change.

van Agt:

I think it is a very important change. Maybe people got too serious. They don't have so much fun in what they are doing. Or they don't allow themselves to feel the fun, also, outside. I don't know. I still like that aspect very strongly, and maybe it will get better. I think people are realizing it, and at the moment in Holland, we are trying to build intra-academic workshops on topics, and I really hope that it will bring back at least a bit of the feeling that we are working together really on this topic. The same feeling we had then in Leiden: we are all working on the 21 centimeter line. Now we know where we are going and it's not so split up any more.

DeVorkin:

More and more people were getting into it, and there were less options for each person going through, and are funds cut?

van Agt:

I don't really know what the reason is. It also has to do with the present completely new generation that are now working at the universities and at the observatories, and they have their own life style. I notice it very clearly. For instance, at Leiden it was common practice that Oort gave, around New Year, a big party, that was really a big party. It went through the whole observatory, through his whole house. You could do the most idiotic things there, the most fantastic things were organized. I once drove in with a motor scooter. All the visitors, at a certain time in the evening, were supposed to act something. One year it was the title of a book. Another year it was the title of a film. And at that time, I think, I had a motor scooter, and I drove into the observatory and through the house and out again, and that was then supposed to be the Roman Holiday or something, a very old film, you have maybe seen it. It was about scooters in Rome.

DeVorkin:

This doesn't happen any more?

van Agt:

That does not happen any more. No. Not in that way, no. I think that's about '63 or something.

DeVorkin:

Are there rivalries between Utrecht, Groningen, Leiden?

van Agt:

Well, I think at that time I was in Leiden, there was a kind of rivalry between Utrecht and Leiden. It came out in remarks that you did not take very seriously, because they did just the sun. That was the center, it was small. But I think there were the normal rivalries you find between universities. At that time, anybody in the Netherlands did not take the Nijmegen University very seriously, because it was Catholic, you know, it was far away south, and so it could not be good, and people reacted funny. But then, you know, I was at the time at Leiden, and Leiden is the oldest.

DeVorkin:

It has a certain and tremendous tradition.

van Agt:

It has its tremendous tradition. I remember in one of those conferences, that the Utrecht people made a big joke out of it, because they did something with -- they acted a play in which they made Simon Stevin, who made the first triangulation -- well, they let them make measures in that play, and the result was that Leiden was not in Holland at all, but was in the middle of the North Sea! Beautiful.

DeVorkin:

Who was this?

van Agt:

I think it was Simon Stevin.

DeVorkin:

I really appreciate the time you've spent with me. Thank you very much.