Interview with Norman W. Broten

Begin Tape 111B

Sullivan

Continuing with Norm Broten on 7 August ’78.

Broten

These systems form the basis of smart arrays, you know, which are used in radar.

Sullivan

In what sense now?

Broten

Well, smart arrays in radar are ones in which the antennas scanned or formed, made to follow something. Well the compound system is part of this system and then by changing the phase between different antennas, you can now make one scan and then it (?) to follow targets.

Sullivan

Did you know about this sort of thing? Was this sort of thing going on in the military at that time?

Broten

No, I think this came after.

Sullivan

Let me just ask this as an aside while it occurs to me. Is it not true that Canadian radio astronomy has never been funded by the military?

Broten

That is correct.

Sullivan

You know, American radio astronomy has had so much input, at that time anyway.

Broten

There has never been any military funding in radio astronomy.

Sullivan

It’s all been through your National Research Council?

Broten

Yes. Almost all. There has been a little bit of work done at a place called the Defense Research Board by a fellow by the name of Ted (?) and Ted Hartz.

Sullivan

Hartz?

Broten

Hartz, H-A-R-T-Z, who was funding by the Defense Research Board, which was effectively a military establishment.

Sullivan

But that was a very minor.

Broten

That was a very small matter, a very small amount, yes.

Sullivan

Alright, now was there any other solar work that you were involved with that we should cover? I don’t see anything else here in the abstracts.

Broten

There were some solar eclipses.

Sullivan

Oh, yes. That’s right. In June ’54, there was one here mentioned. Were there any expeditions that you went on? Or were they just the ones that happen to come over?

Broten

No, I didn’t go on any expeditions. Although Mr. Covington took his equipment off on a solar eclipse expedition in Quebec. But after the Algonquin Radio Observatory was established we had there operating a 10 meter antenna, which Dr. Higgs and I fitted out for 6 centimeter operations - 5 centimeter operation it was, with a scanning beam in which we scanned continuously around the limb of the Sun and watched the Moon bite into it.

Sullivan

I see. What size antenna was this?

Broten

It was 10 meters.

Sullivan

What year was this?

Broten

This was 1953, I think it was.

Sullivan

But I thought you said that you took it to Algonquin.

Broten

That was at Algonquin. 1963.

Sullivan

Oh, 1963.

Broten

Yeah, 10 years later.

Sullivan

Ok, well, speaking of Algonquin, here you have a paper with (Pattenson and Aiken?) in ’58, in which you were doing a site survey for the Canadian National Radio Astronomy Observatory. Could you tell me how this concept came up and then how that developed? The concept for a national observatory.

Broten

Yes. Well, the concept of a national facility had been growing for some time. Prior to this time the need for a national facility was evident. And, a couple of us (?) the fact that our solar observing site near Ottawa was being swamped more and more with both military and airport radars. And so, it was evident that we were going to have to change sites for the solar work as well. So two concepts kind of coupled together. With the permission of the National Research Council, we set out to establish a site for a national facility.

Sullivan

Was there any push to get into non-solar work also?

Broten

Yes. The push was there. For some years the funds weren’t.

Sullivan

Who were the people that were interesting?

NBL: Well, myself chiefly and to a certain extent Mr. Medd.

Sullivan

And another question is, did the optical astronomers have any role in this or were you pretty well distinct from them?

Broten

At this time, we were distinct because at that time government astronomy in Canadian was operated under two branches. One was the National Research Council, which all the solar radio work was done under. And about 1960, ’61, also was the establishment of the Dominion Radio Astrophysical Observatory at Penticton under Mines and Technical Surveys, or something like that. The government astronomy as a whole had been done under a department similar in name to the Mines and Technical Surveys because of the support that the survey people gave to Canada as a whole. And the Dominion Observatory was formed as part of that. And then later on -

Sullivan

In Victoria?

Broten

At Ottawa.

Sullivan

The Dominion Observatory in Ottawa.

Broten

Yes. And then later on the Dominion Astrophysical Observatory in Victoria was formed and operated by the same department. In 1970, I believe, the government transferred responsibility for all astronomy to the National Research Council.

Sullivan

Now but Dominion Observatory and DAO had been around for a long time, had they not?

Broten

Yes, yes.

Sullivan

But you were in not particular contact -

Broten

I was in contact but not -

Sullivan

But not in close cooperation or -?

Broten

That’s right.

Sullivan

Not even with the solar optical astronomers?

Broten

To a certain extent. It was somewhat limited because by this time the site at Ottawa, the Dominion Observatory, had more or less ceased to exist function as an operating observatory, except for the (?? tubes?) and transit.

Sullivan

For reasons of interference also, I suppose?

Broten

For reasons of light interference.

Sullivan

In fact, if I remember correctly from Covington’s papers primarily, I think you may have had good connections with the University of Michigan optical -

Broten

Yes. Helen Dodson and the people down there, yes.

Sullivan

In general, let me ask, when you talked about solar work in the radio, were you talking with the solar optical astronomers or was it pretty much talking to other radio astronomers? Which did you feel more a part of, which community?

Broten

Pre-1960s, I think radio astronomy as a whole was isolated from the optical. In fact, URSI used to be the only place in which radio astronomy papers were given. They were not accepted at the American Astronomical Society. So I think that it really wasn’t until the more galactic work was done that radio astronomy became accepted as a branch of astronomy. It was really considered as an (offshoot?). Reber couldn’t get his stuff published really through -

Sullivan

Well, let’s be fair now, he did get it published in ApJ, even in the early 1940s.

Broten

That’s right. But he didn’t really get much attention from the -

Sullivan

No. Now you say you couldn’t give a paper at a AAS meeting. Do you have some personal experience with that or are you just saying that no one bothered to go to these meetings?

Broten

No one bothered because there weren’t any radio astronomers going to them. So there wasn’t any point in giving a paper there.

Sullivan

One exception I do know about though is the hydrogen work done at Harvard. [Bart J.] Bok, of course, (being a traditional astronomer?). They did give papers. And I think otherwise (???). [Voices obscured by background noise]

Broten

We gave more papers at URSI than at the AAS.

Sullivan

Well, going back to the site survey for the Canadian NRAO, can you tell me what your requirements were and where this lead you in terms of the site?

Broten

The same things as the requirements for any radio astronomy observatory—isolation from interference.

Sullivan

But was it important that it be in eastern Canada, for instance?

Broten

Not essential that it to be in eastern Canada but western Canada was being served by the Dominion Radio Astrophysical Observatory, in effect. And therefore it was more logical to try and establish one in eastern Canada near the large universities in Toronto and Queens.

Sullivan

And especially since you have quite a bit of wilderness in Eastern Canada. But I’m still a little bit confused. Why not just put this thing at Penticton, unless it is a matter of convenience? You are establishing an observatory there about this same time.

Broten

Well, I think that is partly political in that, you know, Canada is a pretty big country and to try and travel back and forth… Travel was even more even more difficult in those days. And the politics of it was such that it was probably easier to get money to establish something which would be of service and of usefulness to the eastern universities, which are large, rather than to put it in the west again. There was one in the west which was established a year before the Algonquin one. At least the site survey was approved a year before. And so really probably more of a matter of politics to establish one in the east, just as you have a fairly large observatory at Caltech and you have one at NRAO in the United States.

Sullivan

Sure. But what’s different is that both of these in Canada are national in some sense. At least one is called Dominion and the other is called National.

Broten

No, the Dominion Radio Astrophysical Observatory is not -

Sullivan

Oh, I see. Maybe that is my misunderstanding.

Broten

- a national facility.

Sullivan

Despite this name which would tend to make it look like it’s for the entire Dominion. Is it really more like the Naval Research Lab in terms of it’s a government funded thing and outsiders don’t really have access to it unless they know the people?

Broten

Well, outsiders do have access to it but by nature the type of instrumentation is more long term program type of thing than it is a short term program.

Sullivan

Visitor-oriented in a sense.

Broten

Visitor-oriented ones come to the Algonquin.

Sullivan

Now, was this the concept right from the very beginning?

Broten

This was the concept from the beginning.

Sullivan

And this is also about the same time that NRAO was beginning to get going in the late ‘50s. Were there any contacts there as to -

Broten

Oh, yes, oh, yes.

Sullivan

- to try to learn from each other about how to do this? Of course, neither of you had a model of a previously existing national observatory. This was rather different from the British and Australia style. Well, another question that pops to mind is that in the U.S., as you are probably aware, there was some opposition from the universities to an NRAO because they felt it would be taking funds away essentially and they were rather dubious about the value. It seems like from what you said that it wasn’t that way in Canada.

Broten

No, I think they wanted because funds for continuing programs, funds for developing major instrumentation is much more difficult to get in Canada for universities than it is for a government agency. If you can get a development grant to build something, the funds for continuing the operation of it are something which aren’t covered under that development grant.

Sullivan

Once you get your foot in the door -

Broten

The university then has to see where to get the funds for this. And to apply year by year for operating funds for something is not very good. So I think that they were happy and pleased in that sense that the National Research Council could provide this. And the University of Toronto always had a very firm interest in the Algonquin Radio Observatory, right from the very commencement of it.

Sullivan

Was that the primary university that was pushing for it?

Broten

Yes.

Sullivan

What were the others?

Broten

Queens University was also pushing hard at Kingston, but to a lesser extent at that time than right now, although they have turned out to be a major user of it.

Sullivan

Okay. Well, having located the Algonquin site, you just mentioned before that you moved up some solar equipment to use it right away. Do I have that right? And that was in what year?

Broten

1960 it started, January 1960.

Sullivan

And what was the plan at that stage for the big dish? What were your goals?

Broten

Well, our goals were for a dish on the order of 150 feet in diameter. And that being sort of the diameter where we thought we could get funds for. Although we were somewhat concerned because of the problems that they had had with the 140 Foot at Green Bank.

Sullivan

Were having.

Broten

And were having at that time. We were encouraged by the very great success which was evident at the CSIRO, the Parkes Antenna. And so we, in fact, opted for going back to the same designers.

Sullivan

Freeman Fox?

Broten

Freeman Fox, since they had achieved something at Parkes which was quite successful. And we went back to them and asked them to design us a radio telescope.

Sullivan

And in what respects does the 150 Foot differ from the Parkes dish? Or is it quite similar?

Broten

Well similar in many (?) ways but it differs from any other radio telescope in that the surface, which is quarter inch plate over 36 meters of it, interacts with the ribs. It forms part of the support structure. So that it is different in that fashion. It is different in as much as we had specified as our (?)— 10 centimeters over 150 feet and 3 centimeters over 120, whereas the Parkes was only specified for 21 centimeters over 210 feet. In fact, we used the whole 150 feet at 3 centimeters and other portions down as far as 1 centimeter.

Sullivan

You have in recent years?

Broten

Yes.

Sullivan

So was this the first time that a dish had been sort of designed for an intersection to have somewhat higher accuracy? Or were you just saying that because you had a somewhat smaller dish you had could push it up to shorter wavelengths?

Broten

I think that would be a fair statement to say, and yet it may not be because Parkes had in mind using the inner 17 meters of their dish at a higher frequency.

Sullivan

Which, of course, they are still working on.

Broten

Which they are working on, and have achieved excellent success. But Parkes and our dish certainly would be the first ones in which they had the concept of better resolution. All the way one recognizes gravitational distortions were towards the edge of the dish (???).

Sullivan

Well, the dish you said got on the air in 1966 or so, so there was a period of six years in there. Did everything go relatively smoothly? Or what were the troubles or highlights during that period of building this facility?

Broten

There were essentially no problems in building (??? the radio telescope?). We had operating at the site a 10 meter telescope on which some work was done. And after the original specifications and the initial design of the 150 foot, the 46 meter was complete, I spent two years in Australia doing some research and came back about the time the dish was ready for some of its commissioning.

Sullivan

I see. Which two years were those?

Broten

’63-’65.

Sullivan

So you were working with the new Parkes dish, I suppose, primarily?

Broten

That’s right.

Broten

What kind of work?

Broten

What kind of work - Magellanic Clouds, polarization of the Galaxy at 600 MHz, some 30 MHz observations, and 5 centimeter observations of the Galactic center.

Sullivan

30 MHz? Using what for an antenna?

Broten

The Parkes dish.

Sullivan

The Parkes dish? Good lord! [Laughter]

Broten

On that I did 30 MHz. The major work which I did there was probably the Magellanic Cloud, the 10 centimeter survey of the Magellanic Cloud.

Sullivan

But this was more or less getting geared up and waiting for the Algonquin dish to get ready, I guess?

Broten

In essence, yes. I felt that I would like to do some research at Parkes and at the same time perhaps become familiar with the problems that I’d have with that telescope.

Sullivan

With a large antenna, yes.

Broten

And therefore get some knowledge of the problems we might have with our own.

Sullivan

And once the antenna was turned over more or less to the radio astronomers, did it operate quite well? Were there any particular problems?

Broten

No, there were no -

Sullivan

It met the specs?

Broten

It met the specs.

Sullivan

Just like the Parkes dish in other words? Freeman Fox delivered again.

Broten

There were no problems.

Sullivan

Now there is one other topic which we should talk about that just occurred to me. That is, you were involved, were you not, in the first successful VLBI in Canada. So I would like to hear in closing about that effort. How did this idea come about, and could you just tell me the story?

Broten

The idea had a germ back in 1961, I guess it was, at the opening of the Penticton dish. And at the same time Canada had a radar station operating at Prince Alberts, Saskatchewan, about 1000 kilometers away from Penticton. And at the opening of this Penticton dish there was a suggestion that the Penticton dish and the Prince Albert dish might be used together as an interferometer, although a very basic suggestion. And the concepts had not been worked out. In fact, any thoughts were perhaps faulty at that time. And it lay there dormant for a number of years.

Sullivan

Excuse me, but the idea was that there would be independent recording of the signals and then later combination?

Broten

Yes, yes. The idea lay dormant then until about 1965, about the time I returned from Australia. And I’m not too sure who sort of started it again, Herb Gush from the University of Toronto, Alan Yen or Dr. Locke. But I met with Dr. Galt at Penticton on my way back from Australia and he says, “Have you heard anything about the idea of doing long baseline interferometry?” I said, “No, I’m just coming back.” So he briefed me in it and then we joined in with the group in October of ’65 to supply some funds and knowledge and manpower.

Sullivan

You say we joined in?

Broten

The National Research Council.

Sullivan

I see. It had not been previously involved.

Broten

Well, there hadn’t really been anything concrete done. The first organizational meeting was in October ’65, just a general discussion between ourselves. Of course, some discussion had gone on before I came back from Australia between, I think, the Penticton group and the University of Toronto group. It hadn’t really gone too far at that stage and none of the concepts had been worked out. The National Research Council then supplied almost all the money for putting the long baseline interferometer together, a good deal of the manpower in terms of our engineers and our astronomers, too. So we had a fun two or three years getting it going.

Sullivan

What was the key that made people think about this? Was it all of a sudden the availability of rubidium oscillators or - ?

Broten

No, no. The experiment could have been done 15 years before.

Sullivan

15?

Broten

Yes. The key really was the discovery of sources whose amplitude fluctuations were short duration. That is to say, sources that varied on the order of a few months and therefore had to be very small diameter cores.

Sullivan

I see. So you mean in the ‘50s no one would think that there would be milliarcsecond sources?

Broten

That’s right. No one dreamed that there would be anything (milliarcsecond sources on the order of months or weeks of diameter?).

Sullivan

And so these microwave short periods of variation that were discovered around ’65, ’66, you’re saying were the - ?

Broten

The (?), yes.

Sullivan

But now, fill me in. I didn’t realize that technically this could have been done so early.

Broten

The tape recorders we used were traded-in CBC video tape recorders from that they’d had for ten or 15 years. The hydrogen masers we used for the last of the (???) were experimenting with. They had hydrogen masers going before that. Rubidium clocks had been around for about 15 years. So the whole experiment could have been done before.

Sullivan

I didn’t realize that. So it was really mainly the astronomical knowledge that tipped it off rather than the techniques.

Broten

Well, certainly the idea of how to put these techniques together required a bit of work and a bit of thought, you know, how to do it. But the need for doing it was not really evident before.

Sullivan

Or might one say that one also had to have the experience primarily at Jodrell Bank and somewhat in Australia, moving on to longer and longer baselines and - ?

Broten

Yes.

Sullivan

- and still getting fringes?

Broten

That was Jodrell Bank that did that. It wasn’t Australia at that time. Yeah, there is certainly some of that but, of course, I think the clue to anyone thinking in terms of this was the fact that sources were varying in the order of weeks and months in intensity. No way could we do this if they were very large sources.

Sullivan

Yeah, yeah. Well, tell me in terms of the actual observing, once you had put together a system, did the fringes just fall out?

Broten

We had our problems, like the American group did.

Sullivan

Were you knowledgeable that they were going on - ?

Broten

Yes. Ken Kellermann and I were in weekly contact with each other, finding out what our status was. It was a very friendly rivalry going on between us. And, yes, we had some problems in getting it operating. And we opted to go for the whole distance between Algonquin and Penticton to start with, after having done an experiment on site between the 10 meter dish and the 46 meter dish, just separated by 200 meters. And so we went out to Penticton and played the tapes back and got nothing. And so we got a little worried about that so we then pulled our tape recorder and oscillator back to Ottawa, some 186 kilometers, and got all kinds of stuff. And essentially the same sort of thing happened in the United States. They got fringes to NRL but they didn’t get any -

Sullivan

From Green Bank, right.

Broten

They didn’t get any fringes to Arecibo. Well, we went back to our tapes we had taken and played them and finally discovered that what we had was a very small time jump in recording, a few microseconds. And so our correlation wasn’t at the spot we thought it was. And we did that and then found our fringes loud and clear.

Sullivan

I see. So you weren’t searching assuming different clock errors?

Broten

Oh yes, we searched but it isn’t quite the same, you know.

Sullivan

Yeah, when you really know where you should be looking, you look hard.

Broten

Our techniques were more rudimentary at that time. We didn’t do quite the same we do now.

Sullivan

And I suppose that when you obtained the fringes on the short baseline and not on the very long one, you weren’t sure whether you’d resolved the source or something hadn’t worked also.

Broten

There are always these possibilities, yes.

Sullivan

But was there any attempt then at an intermediate sort of baseline?

Broten

No. After we had success, which was announced at a joint US-Canadian URSI, 1967 in Ottawa -

Sullivan

I didn’t realize that. How appropriate.

Broten

Well, it’s even more astonishing than that. Dr. Yen and I had been up trying to get this correlation in the tapes at our observatory where we were doing it, and had just finished working about 24 hours when we got the first fringes on a Saturday. We worked then all day on Saturday and Sunday morning, yes. We worked all day Sunday to get these better and defined. We drove down without any sleep to Ottawa and Monday morning presented them at the conference. [Laughter]

Sullivan

I see. Had you already sent in an abstract about this?

Broten

No, no.

Sullivan

This was an unscheduled paper.

Broten

We were to speak to speak at URSI on the idea -

Sullivan

The idea, the technique.

Broten

Yeah. The technique and that. So it was the American group under Marshall Cohen, who was also to speak at it.

Sullivan

Okay, well, now let me ask you a general question. If someone in the late 1950s said at a cocktail party or something has said “What do you call yourself?” or “What do you do?”, what would have been your answer at that time.

Broten

In the late ‘50s?

Sullivan

Yeah.

Broten

I would have called myself an astronomer.

Sullivan

An astronomer? You wouldn’t even have said radio astronomer? I see. So despite the fact that you weren’t invited, so to speak, to astronomical meetings, you still called yourself an astronomer.

Broten

Yes, I think that the feeling has always been that radio astronomy is (just another phase?) of astronomy. I don’t think the feeling has ever been any different.

Sullivan

Amongst the radio astronomers anyway.

Broten

Amongst the radio astronomers. The reason why URSI was used more than AAS was for two reasons, maybe three reasons. One that they didn’t feel at home giving their papers in the optical sessions. But more that in the early days, a great deal of what you were doing was technical. And all the early radio astronomers were also technical people who did some of their own work. Nowadays people graduate in astronomy and expect the equipment to work. But that was not the case. We had to build our own equipment, everything. So URSI was a place where you came and gave your technical results, where you came and presented your astronomical results, and where you met other radio astronomers. In the early ‘50s, there probably weren’t more than about 50 radio astronomers around the whole world and you knew them all.

Sullivan

Right. Thank you very much. That finishes talking with Norm Broten on 7 August ’78.

End Tape 111B