NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with E. G. "Taffy" Bowen
At the Australian Embassy
December 24, 1973
Interview Time: 1 hour, 10 minutes
Transcribed by Bonnie Jacobs

Note: The interview listed below was either transcribed as part of Sullivan's research for his book, Cosmic Noise: A History or Early Radio Astronomy (Cambridge University Press, 2009) or was transcribed in the NRAO Archives by Sierra Smith in 2012-2013. The transcription may have been read and edited for clarity by Sullivan, and may have also been read and edited by the interviewee. Any notes added in the reading/editing process by Sullivan, the interviewee, or others who read the transcript have been included in brackets. If the interview was transcribed for Sullivan, the original typescript of the interview is available in the NRAO Archives. Sullivan's notes about each interview are available on the individual interviewee's Web page. During processing, full names of institutions and people were added in brackets and if especially long the interview was split into parts reflecting the sides of the original audio cassette tapes. We are grateful for the 2011 Herbert C. Pollock Award from Dudley Observatory which funded digitization of the original cassette tapes, and for a 2012 grant from American Institute of Physics, Center for the History of Physics, which funded the work of posting these interviews to the Web.

Sullivan

Ok, this is talking with E. G. "Taffy" Bowen at the Australian Embassy on 24 December ’73. Can you tell me a little bit about how you began in the whole business?

Bowen

Well, let me give you some pre-history. I was involved in the first air-warning radars in England, of course, in 1935. And the first piece of equipment we built to get reflections from aircraft was essentially a high power ionospheric set running around 100 kilowatts in output. And at that time, apart from echoes from aircraft, we had two observations which would have been of great scientific interest if we'd been able to follow them up. But, of course, we couldn't. The first of these, speaking with hindsight, of course, is that we were getting enormous numbers of echoes from meteors- about 120-140 kilometers. We knew they were in the ionosphere, but we didn't realize that they were meteors at that time.

Sullivan

Echoes from their trails more exactly, I guess.

Bowen

Yes, and, of course, it was [James] Hey who much later realized what was going on. We were too busy looking at other directions to follow it up. The other observation which is relevant is that when the ionospheric conditions were suitable we were getting long distance echoes from the European mainland, from Norway, Scandinavia, in fact, we were pointing in that direction, across the North Sea. And again we realized what was sending the signals back, and of course we could recognize at times when we would in fact break through the ionosphere and look straight out. Well, that was around about 1935, 1936.

Sullivan

Let's go back a little bit more pre. You are an Australian I'm sure...

Bowen

No, I'm British.

Sullivan

Oh, you're actually English. So that's why you were in England, ok.

Bowen

Yeah, and as I tell you I didn't get to Australia until 1944.

Break

Sullivan

So you were working on this radar during the War and you mentioned also about antenna temperature. Can you...

Bowen

Yeah, well what I just described round about 1935, ‘36. But certainly by 1939, before the War had started in 1939, when we knew we were breaking through the ionosphere and looking out into outer space. We were certainly talking at that time, in rather vague terms, first of all of matching or mismatching the antenna system to free space, which is a theoretical concept, but we were also speculating about what noises in fact we would receive. We were thinking in terms of low noise temperature [?] and so on. But that concept was normal to us in 1939.

Sullivan

And you did know about [Karl] Jansky's work, I presume?

Bowen

Oh yes. Jansky only- I knew about Jansky's work at that time, but I didn't know about [Grote] Reber.

Sullivan

That's right because he didn't publish until '40 the first paper.

Bowen

I've really forgotten.

Sullivan

Let me also ask - what frequencies were you operating at?

Bowen

The original air-warning radar- 1935-36, was in fact 50 meters, which we quickly pulled down to 26 and then to 13 meters, so somewhere in there - 13 to 26 was where we were breaking through the ionosphere. That was the reason for coming down of course. The ionosphere was giving us a lot of trouble.

Sullivan

And I suppose also you got more definition [Sullivan: angular resolution] or were you worried about that at all?

Bowen

Oh no, we were definitely- of course there were equivalent limitations with stuff going down too far. Well, I think the next significant item relates it to radio astronomy is the fact that I came over to the United States in the ‘40s. I was involved in or in effect the beginnings of microwave radar at the Radiation Lab at MIT, and in the course of that I became familiar with two or three or four things which relate to radio astronomy. Well, the first probably was probably was [George] Southworth’s measurements on 10 cm I think, of solar temperature.

Sullivan

Right. That was actually done at the Bell Labs.

Bowen

That was done at Holmdel at the Bell Telephone Labs with his own equipment which, of course, Bell Labs were working on as extensively as MIT, especially in the receiver end.

Sullivan

Was this sort of a parallel effort?

Bowen

Partly parallel, partly contracted, and I would say that they were the receiver experts. But they easily had their heads in front- Southworth, [Harald] Friis, [C. R.] Englund, and a few people like that.

Sullivan

And what was the expertise at the Radiation Lab?

Bowen

Well, very close to it and derived from it I would say. So, Southworth's measurements, I remember talking to Southworth about them, seeing his equipment - I didn't actually see it pointed at the Sun. I didn't read his reports at that time, but I was familiar with his 6000° and the [Sullivan: later] fact that he was wrong and corrected that to something like 20,000°.

Sullivan

Exactly. But did he issue a report at that time? [Sullivan: Yes, 1942-43]

Bowen

I'm not sure that he did.

Sullivan

I've never seen a reference to any.

Bowen

No, I don't think so, it was material in his notebooks and so on.

Sullivan

It seems peculiar, because that would be of interest to the military and so forth, wouldn't it?

Bowen

No. I think it's indicative of our overall thinking at that time- stuff branched off of the ionosphere, "breakthrough," matching an antenna at free space, all of these were peripheral things. The main objective was, you know, something to do with detecting an aircraft or a ship or what have you. I think this a rather important comment. I don't know quite how to formulate but anything these people did, Hey and so on, was peripheral in those days.

Sullivan

Yeah, that's right.

Bowen

Well, that was Southworth. I was familiar with what [Robert H.] Dicke was doing at the Radiation Lab on 1 cm...

Break

Bowen

I was familiar with Dicke's measurements on the Moon on 1 cm. I left the Radiation Lab to go to Australia, we’ll come to that in a minute, in '44. But my present recollection is that Dicke had already measured the temperature on the Moon in January '44. Of course he didn't write it up till later. I could be wrong about that.

Sullivan

He didn't even write up that measurement though, ever.

Bowen

No.

Sullivan

If indeed that's correct.

Bowen

I could be wrong about that, as I say my recollection isn't entirely clear. I certainly didn't see any reports at that time.

Sullivan

I'll check with him on that.

Bowen

Yeah, But he wrote it up later, '45 and '46 I believe, when the whole thing jelled. I have it in the back of my mind that he’d done it prior to January '44. And, of course, in the same context I certainly knew about Hey’s observations of the Sun in '42, reported in the Army Operational Reports in England. And lastly it was at that time that I became aware of Reber's work. I was familiar with Jansky from way back, of course, but not Reber's until the Hey and Southworth work sort of brought it into focus.

Sullivan

Something just occurred to me. How did it happen that Reber stayed out of the War effort? I've never thought of this before.

Bowen

I don't honestly know. I have no idea at all.

Sullivan

He must have had the biggest dish in the world in the middle of this huge war and...

Bowen

Yes, that right. No, I can't answer that at all.

Sullivan

Well, related to this, I'm interested in the development of paraboloid dishes. Was Reber’s indeed the first dish of that size?

Bowen

First of any size. I should say the first ones that came into use for radar purposes were the airborne radar dishes which were 30 inches in diameter.

Sullivan

When was that?

Bowen

That was in 1940.

Sullivan

So that was actually after Reber's...

Bowen

Oh yes, well after. And I can claim some responsibility for kicking that off and for the later 30 inches. But I was involved as you probably know in '38, '39, '40 with the airborne radars in England. The air-to-air radars and the sea search radar...

Sullivan

No, I'm afraid I don't know.

Bowen

Which were on 1.5 meters, which was the shortest wavelength that those techniques of that day could get us down to. Now the trouble with a wavelength of 1.5 meters is that it's "all-around looking" so we were very much disturbed by the direct signals from the ground. In fact you had to get to 15,000 feet before you could detect an aircraft at a range of 3 miles because the ground echo was always so strong you can't do anything about it. And it was at that time that we explored the question how short do you have to go in order to eliminate an echo from the ground. And the answer was 10 cm - you had to get right down to 10 cm. Oh, this by the way was determined by the size of the antenna which he could put on an aircraft.

Sullivan

That was the limiting factor?

Bowen

In the night fighters of those days, such as the Mosquito, you had about 3 feet and you could put an antenna of 30 inches. And that was the dimension for a very long time.

Sullivan

And this was actually located right up by the nose?

Bowen

Right in the nose.

Sullivan

I guess that's right. It was mainly for use at night because in the daytime you could presumably just see the other guy or poor weather, I guess.

Bowen

Sure. But the air to ship radars had very nearly the same limitation. There was only a limited aperture up front to put an antenna. These were when the first parabolic antennas were used for radar purposes, and then shipboard radars came later with bigger apertures, of course. And with then ground installations with still bigger apertures came into the picture but that wasn't until, well into '42 or thereabouts. So why Reber...

Sullivan

So he must have dreamed this up all by himself so to speak.

Bowen

With his 30 foot - was it 23 foot?

Sullivan

31 I think.

Bowen

31 foot, why he didn't come into the picture for wartime radar, I don’t know.

Sullivan

Well, I'll have to ask him that. So what was your main effort at the Radiation Lab?

Bowen

Airborne radar- just by way of comment, it isn’t relevant, I put the first airborne radar into a US aircraft, here on the Potomac in October 1940.

Sullivan

Right, at Bolling or at NRL [National Research Laboratory]?

Bowen

No, in the Anacostia River. It was a PBY flying boat.

Sullivan

I see, right in the river.

Bowen

And we used to fly over the Atlantic checking ships, and that was at the time when the German submarines sinking freighters off the coast. So it made quite an impact and there was a big airborne effort in the US of course at 1.5 meters, prior to the microwaves coming to the picture. But those were my two activities. I put the 1.5 meter airborne radar business into operation in the US and I helped with microwave radars at MIT.

Sullivan

Another related question which you might be able to help out on. Why is that you think the American radars never picked up things like Hey picked up? Is it just accident they didn't get a solar burst...

Bowen

I think it is. Surely - probably accident and probably most of the US radars that showed up in Europe were microwave and narrow beam, so they perhaps didn't spend a long enough time looking at the Sun.

Sullivan

And not as low frequency either...

End of Tape 29A

Sullivan Tape 30A

Sullivan

With Taffy Bowen on 24 December ’73.

Bowen

Hey’s equipment was much lower frequency. Therefore more likely to get something from the Sun, which is also much wider beam.

Sullivan

Also because of a wider beam, right.

Bowen

So the Sun would stay in for a much longer time.

Sullivan

You don't know anything about what the Germans were doing parallel to this, do you?

Bowen

In radar, yes. As far as I'm aware they had no concepts of radio astronomy.

Sullivan

Well, can you say a little bit about what they were doing in radar?

Bowen

Oh yes. In 1939 and 1940, the beginning of the War, the German military certainly had no concept at all of what you could do with radar and they walked right into it. It was a complete absence of knowledge on their part during the battle of Britain. That led to our winning that one. If they'd come in at 50 feet over the North Sea for example, there would have been no warning. They had no concept of the operational use because they didn't have equipment. But they caught up very fast and their principal developments were around about 50 cm. They had both the receiving and transmitting equipment to do it and by 1942 or '43 they probably had better radar covering Europe - air warning cover - than we had in England.

Sullivan

Because the equipment was better or because it was more complete?

Bowen

Oh because the equipment was better. It was that much later. We still had the old stuff operating in England. It's the old problem- you're stuck with the old techniques. But the German radar cover was built up during that period, 1940 to 1942, so by mid ‘42 - '43 they were in very good shape. Also, the one other place they had an advance was that they did have a radar ranging set in the Navy, on their battleships, and if you recall they had some pretty good successes on the Bismarck. They sank some ship that was chasing them, and that was because of radar range. They had very good range out of [?].

Sullivan

Why was it that they developed these marvelous Würzburg dishes which were so important to every other country for radio astronomy after the War?

Bowen

I think just good German engineering. That they always specialized in heavy engineering. They also had, come to think of it, some prior experience with a dish on the Brocken. Do you remember that name?

Sullivan

Is it a ship?

Bowen

The Brocken is a mountain in the middle of Germany. They had a dish there operating before the War.

Break

Sullivan

So you have a recollection that on the same place as the modern Stockert dish, there was a large one pre-war.

Bowen

Right. Probably the Würzburgs, derived from their experience with that. Telefunken was the main company.

Sullivan

I have talked with [K.] Fränz actually a little bit about his role, only on the telephone, but that was interesting.

Bowen

Set me going again.

Sullivan

So I think you've covered all that you heard about radio astronomy during the War.

Bowen

By the time I went out to Australia in January 1944...

Sullivan

I should ask about these reports: I've seen a reference to a New Zealand Air Force report about picking up the Sun during the War, do you know anything about that?

Bowen

No. I think I remember [Joseph L.] Pawsey mentioning it.

Sullivan

Right. He quotes it.

Bowen

I can't remember it at all. Well, I went out in January '44, still on loan from the British by the way, from the Air Ministry for two years to help with the radar effort in the southwest Pacific. Of course, the MacArthur American headquarters was in Brisbane in Australia at that time, so I spent the next 2 years helping with the radar effort there.

Sullivan

Was it a separate development going on there, or was it more a matter of...

Bowen

Oh, it had been stimulated from England in 1939 and there was the Division of Radiophysics at that time in existence at that time especially for radar work as the Radiation Lab was specially set up. There was an interesting transition at the end of the war- or when the end of the war was imminent - some big decisions had to be taken in Australia and they were taken at the political level that CSIRO would no longer after the end of the war do military research. This would be done by the Defense people, the Department of Supply, and so on. The Division of Radiophysics would revert to peace time Radiophysics. So in 1946 I first of all had the choice as to whether I'd go back to England or stay in Australia. I had offers from both places and decided to stay in Division of Radiophysics as Chief of Division.

Sullivan

Is that where you worked from '44 also on?

Bowen

Yes. I was Deputy Chief in '44 to '46 and I had the offer of Chief of the Division in '46, so I took that. Now the main job I had to do in '46 of course was to recast the research program of the Division, which was a delightful task because here was a going laboratory. It had 200 people, we had stacks and stacks of wartime equipment either available to us or readily accessible. So we started a wide ranging program covering a number of fields, what we thought were promising fields like radio navigation, applications of radar to various civilian activities like surveying. But one of the most exciting things that we started to look at, of course, were all these radio astronomy matters which we knew about, and then would follow-up in an active way.

Sullivan

Did you start on rain physics that early?

Bowen

Well, rain physics too. We had been using airborne radars to look at echoes from ice crystals and snowflakes in the cloud in a casual kind of way. In the latter part of the war. It was perfectly obvious there were a lot of processes going on in clouds which the meteorologists didn't know about, so these were worth investigating. So that was a big program. And our intentions were quite clear, to try 3 or 4 or 5 of these promising things and not necessarily continue on, but put an intensive effort into whatever looked the best. The two that really came out, of course, of that were radio astronomy on the one hand and rain and cloud physics on the other. And this of course is where a good number of other people came into the picture, particularly Pawsey. And he became easily the most active and stimulating individual on the radio astronomy side. He was aware of all the same things that I've mentioned- Hey's work, Southworth, Dicke and so on.

Sullivan

What was his background? I know he got his degree at Cambridge, but can you briefly tell me what else?

Bowen

He was Australian born, University of Melbourne, had an 1851 Scholarship, which is one of the best you could get in those days to Cambridge. Took his higher degree in Cambridge. Then he worked for EMI on antenna systems, particularly transmission lines and antenna systems. He had a big part in building the first TV transmitting antenna at Alexandria Palace in London. That was the first TV transmission in England.

Sullivan

So he stayed in England then?

Bowen

Until the War had already started, I think. I forget when he took his degree, his PhD in Cambridge...

Sullivan

It was '32 or '33, I think. I happened to see his thesis when I was there.

Bowen

That's right. And he worked for EMI let's say up to 1939, at which point he went back to Australia to get involved in the war effort there. And either he spent some time with us at Bawdsey by direction of the Australian Government, before going out to Australia, or he came back again and spent quite some time - 3 or 4 months picking up the radar techniques.

Sullivan

Where was that again?

Bowen

In Bawdsey. That's the Air Ministry Research Station.

Sullivan

Near London?

Bowen

90 miles east of London, up the east coast. Bawdsey Research Station, which is where all that work was done. So he spent some time with us. That would have been before the war. And later, of course, he spent some time with MIT in the Radiation Lab picking up the microwave stuff.

Sullivan

No, I didn't know that.

Bowen

Yes.

Sullivan

During the War?

Bowen

Yes. That could have been '40 -'41.

Sullivan

That's when you were there also?

Bowen

Well, I vaguely remember- yes, that's right which was when I was there also. And whether that was a separate trip from Australia or whether it was the same trip I can't recollect. Anyhow, he had plenty of contact with these endeavors and [?] but even during the war we used to talk a lot about wouldn't it be nice if we could get onto this kind of stuff. Just by way of reminiscence by the way, Lovell worked for me during those years in England.

Sullivan

At this same station?

Bowen

At Bawdsey, the same station, yes. You might recollect from the record that the Cambridge physicists were recruited lock-stock-and-barrel and were distributed among the Air Force, Army and Navy. Cockcroft, for example, took charge of the Army radar, [A. C. Bernard] Lovell and a good many others came to us and he was working for me. [Martin] Ryle was another one. He wasn't reporting to me directly, but he was working on adjacent work.

Sullivan

The same station?

Bowen

Yes. So there was a lot of common elements.

Sullivan

It also appears that the American, British, and Australian radar groups were very much in contact.

Bowen

Yes. I was perhaps the first British liaison officer to come over here, to set up the British-American links. And by '41 certainly, there were Australian people from the Division of Radiophysics here in Washington, and several who spent quite long periods at the Radiation Lab and elsewhere in the States. So the links were very, very close.

Sullivan

We were talking about Pawsey's background. So he worked at the Radiophysics Lab from '41 or after he left the Radiation Lab...

Bowen

Oh, that was a visit. From his return to Australia in 1939 in fact he worked for the Division of Radiophysics, including these visits to England and to America, and he was predominantly working on air warning problems through the war with particular reference to the antennas and feed systems. So it is a natural that we'd pick up a radar, set it on a cliff and look at the Sun and so on is what we did. The next event of significance, I think, is my decision to go for radio astronomy.

Sullivan

When was that decision made?

Bowen

We were in fact going for it in 1946 and it was during 1946-47-48 we were building up staff. We already had a hard core of extremely good people, mostly engineering. Well, there were a number of people with a joint B.Sc/B.E. from Sydney University, and it surprising how often that degree comes through. Practically all the people in the Division of Radiophysics had this joint physics/engineering degree and it proved extremely useful. But we were looking for staff and we got around half dozen in the next year or two. But two in particular, of course, were John Bolton and [John] Paul Wild. An extraordinary coincidence that they both came from the same roots and by the same route. They were both born in Sheffield, they both took short Cambridge degrees in physics during the War, '41 and '42. They then went into one on the British Navy, they were radar officers, one on the King George V and the other on an aircraft carrier. And they ended up in the British Pacific Fleet in Sydney Harbor at the end of the War. They liked the place so much they started looking around for jobs. We only had one position we were advertising - and both Bolton and Wild applied for it and Bolton got it. So we took Bolton literally off the ship Sydney Harbor. And that was the British arrangement: their officers could demobilize in Sydney or back in England. John Bolton we took on. Paul Wild went back. He applied for the next vacancy we had, and again was refused for some reason. We had a better appointee and then something else happened and we appointed him. But I remember interviewing him in London for that job, I think in 1948. So we probably appointed Bolton in ’46 or ’47 and Paul in ’48. Incidentally, have you seen the recent issue of Nature?

Sullivan

No, I haven't.

Bowen

Which has got an article by John Bolton which covers some of these things.

Sullivan

I see. Yes, I'll check that. I still haven't quite got the answer yet as to - it seems like, you very quickly made the decision that you wanted to go with radio astronomy, within a year or something it would seem.

Bowen

Easily within a year.

Sullivan

Once you started?

Bowen

Sure. Well, the potential was so good, and as you’ll find in the literature, of course, Pawsey struck it extremely lucky in February 1946. The biggest sunspot there’d been in all these years. And he did all that beautiful direction-finding work. Really got the thing on the map and that was well in front- we knew all this well in front of publication, of course.

Sullivan

Yeah, the publication was somewhat delayed on that.

Bowen

Yes, which in some cases we were very cross about. We think it was not deliberately delayed, but people were not pulling their finger out to bring the Australian effort to the floor. There certainly were cases in which we had made some observations first. Ryle heard about them, followed them and made the observations and he got his publication in before we did.

Sullivan

Well, their style was much more something in Nature.

Bowen

Yes, well so did we. We caught up...

Sullivan

Then you started, yeah. Let me ask, is it correct to say that the first work with the cliff interferometer was really using exactly the same techniques as had been used from ships for ranging, so that these thing had all been worked out, to do with the refraction and...

Bowen

Ranging and height finding. That was the technique for height finding and was used prior to the War- 1938. This was the technique for height finding we used it at Bawdsey in 1938.

Sullivan

I see. So that was developed in England?

Bowen

Yeah. So I sometimes worry about this on the grounds that I don't want to detract from what Pawsey did for one minute. But even our own people got "goggle-eyed" about this, that Pawsey in fact invented the cliff interferometer. Far from it. That was a pre-war invention.

Sullivan

It was just a very clever application of these techniques to astronomy.

Bowen

Right. And the realization that it was an interferometer jelled about then.

Sullivan

And also I think that is the first mention of the idea of a Fourier transform in that paper by [L. L.] McCready et al.

Bowen

Yeah, That really put it on an entirely different footing. But the concept of direction finding on a minimum instead of on a maximum was pre-war ~1938. Which goes right back, if you like, to Friis’ and [?] in the USA. They used a big array. There were similarities there. There was corresponding work in England done by Wilkins, who was the other man involved in the radar thing. He was doing the downcoming angle measurements on the transatlantic path at the English end, and Friis was doing it at the US end.

Sullivan

Downcoming angle from the ionospheric reflection?

Bowen

Yeah, that's what Friis was doing, essentially. He was waving the maximum of his beam up and down and determining downcoming angle. Wilkins was doing it by staying at minimum. He didn't have a big array, only an interferometer. So it's an old technique. Well, let me think. You know all about Pawsey's work on the Sun so I needn't expand on that.

Sullivan

Well, I know about it only from what's published really. Anything you could tell me...

Bowen

I don't think there is anything additional that needs to be said, apart from this point which I just made.

Sullivan

Another thing that has struck me though is the way that it seems like the Radiophysics group was hauling their antennas on their backs all over southeastern Australia. I suppose this is because they were just used to this. I mean these were radar, very portable outfits and so they took them wherever it was most convenient.

Bowen

We were very noise conscious and more particularly anxious to get out of metropolitan Sydney, of course, because we could get to such low noise regions rather easily.

Sullivan

Right, using different height cliffs and things like this.

Bowen

Sure. Now the other two significant events I think are reasonably well covered in the literature, except perhaps the next breakthrough as far as we were concerned was Bolton's observation of point sources and identification of point sources, Crab Nebula and what have you. Now that again was done well in advance of what appears in the literature. We were thoroughly familiar with the fact that they were point sources up there and they could be identified with things long before the Cambridge group were on the ball. And I personally did a lecture, I can't recall the details, at the Cavendish Laboratory in 1946. I told them two things: one was that the temperature in the outer region of the Sun was a million degrees and the other was that you could identify point sources [Sullivan: see EYRA, p. 89]. And Ryle got up and denied both of them.

Sullivan

In '46 it was the identifications were already known- that early because it wasn't published until '48.

Bowen

Sorry. I'm terribly sorry on that. Now I may be wrong about that date. I was certainly in England in '46 and I was also there in '48. So perhaps it was '48. Anyhow, in advance of publication of any of this by the Cambridge group...

Sullivan

Right, well that paper by Bolton, [Gordon J.] Stanley, and [O. Bruce] Slee is certainly a classic paper, where they have the three identifications. But let me ask about a previous paper by Bolton alone. He has what turned out to be indeed valid radio sources, but the positions are vastly wrong. Off by 15 - 20°. They're really wrong.

Bowen

I see.

Sullivan

And then later there is a reference by Pawsey in a review that he got his refraction calculations wrong, apparently. But what I don't understand is how he did that when all these techniques were so well known, like we were just talking about. Because he was using the sea-cliff interferometer also.

Bowen

No, I can't comment. Refraction error wouldn't be more than a degree.

Sullivan

I guess I'll have to ask him. There were about 7 sources- for instance he had Virgo A in Coma Berenices. And you can see what each source is now, but they're quite a bit off. But then of course when they did the later paper just a few months later actually, it had all been tidied up somehow.

Bowen

Well, that was a big event as far as we were concerned. The other was Paul Wild's work on spectroscopy of the Sun. And here again of course is a very simple connection back with radar or the radar days. You’ll recall that the spectrographic work on the Sun began with an observation of a burst on two different frequencies by John Bolton and Ruby Payne-Scott, which were about 1 minute apart. And there was a hell of a discussion went on as to whether the clocks were right, you know, that kind of thing. And I well remember, quite acrimonious as to how to do this experiment in a reasonable kind of way and they were all talking in terms of clocks and tie lines and God knows what. I got thoroughly irritated, and said, "Look for God's sake, in the room above my office were all the intercept receivers used during the War to check on German and Japanese radars."

Sullivan

That's to determine their frequency, you mean?

Bowen

Yeah. Sweep receivers - they just swept through...

Sullivan

And then to jam them...

Bowen

Yeah, displayed the incoming signals on a cathode-ray tube, pick the frequencies, and jam them. But they were quite sensitive receivers with a 2 to 1 frequency range on a rotating condenser. So there they were. And you pick your waveband you see and pick the receiver. So I said for God's sake, go and get one of those, connect it up to a wideband antenna and you've got the answer. That has been forgotten by the way. Other people now take credit for the use of the sweep receiver, but- I clearly recollect I was the first to tell Paul Wild to go and do it in no uncertain terms. If anybody wants to check me on that I also have a pre-war patent for a navigation system based on a swept receiver. I think it's dated 1934 or thereabouts. In other words I was fairly familiar with swept receivers so that's how the spectrometer...

Sullivan

That's interesting. I didn't realize that that came directly out of radar.

Bowen

Oh yes. So Paul grabbed that and in a way that went to an extraordinary extent. Perhaps the only other early thing I haven't covered properly is Pawsey's million degree work on the Sun, which he had wrapped up pretty early. And he became very full of this question of what is an antenna looking at and what is the noise source and all the rest. And for a time, if you recollect, he reverted to long wave upward looking receivers in which he measured the temperature of the ionosphere.

Sullivan

I see. No, I didn't realize that.

Bowen

Noise temperature of the ionosphere, yeah, at different depths of penetration using different frequencies.

Sullivan

When was he doing this?

Bowen

This was in 1948; there were some papers by Pawsey and [Francis F.] Gardner.

Sullivan

Oh, that's right - not in the Australian Journal of Scientific Research, I think. But I think I have seen references to them because...

Bowen

Yes, in the J.IEE [Journal of the Institution of Electrical Engineers] in England, I think. So all this is relevant.

Sullivan

Right, he was thinking of the analogy with the solar atmosphere and corona...

Bowen

Right. He first of all did corresponding measurements in the ionosphere, so it was a small translation to take that to the Sun. And D. F. [David] Martyn was involved on the theoretical side. He picked this up pretty smartly, as recounted by Hey [Sullivan: 1973 ERA].

Sullivan

Do you agree with that story?

Bowen

You’re damn right. He’s got it dead right. Martyn was a rogue- he tried to make out that he thought of it all first and then told Pawsey to take the measurements. Absolutely wrong- Pawsey had done them first and knew the answers.

Sullivan

But it's funny though that in the actual paper Pawsey gives a credit to Martyn for suggesting this problem, or something like that. It doesn't look at all like Hey's story, but is this only because Pawsey was being a diplomat?

Bowen

Yes. Pawsey was being- I should not for the record - I mean you can record it but don't say anything about it. D. F. Martyn was the original Chief of the Division of Radiophysics and got the sack, and I replaced him. So it was a very difficult situation. Pawsey was the nut in between the jaws of the nutcracker.

Sullivan

While we are talking about this obliquely anyway, the collaboration between Stromlo and CSIRO seemed to be pretty good, for such an early stage anyway...

Bowen

Good and bad. Let me give some credits in the reverse. That the Director of Mount Stromlo at that time was Woolley, later Sir Richard Woolley, Astronomer Royal. He was the biggest enemy we had in the development of radio astronomy, when he was sitting at Canberra, which is among the heads of government. And he made no bones about it that he regarded this as a waste of time and a waste of money. And he used to tell politicians that, "Money is being wasted on this radio astronomy, and for God’s sake cut it out."

Sullivan

Is this because he couldn't understand it, or...

Bowen

He couldn't understand it. All these traditionalists from way back- having positional astronomy was all right, but all this new-fangled stuff full of tubes and this kind of stuff, computers.

Sullivan

He did write a paper in '48 in Monthly Notices in which he commented about HII regions and how they might create radio waves.

Bowen

Yes. That's true.

Sullivan

Did he come around a little bit by then?

Bowen

He'd come around a little bit. He wasn't still seeing the light. He didn't agree with money being spent like that, but he gladly would accept that some of these things might have a reality. Well, [Ronald N.] Bracewell, if you talk to Bracewell, has a very good story which I'll repeat for you. At an ANZAS [Australia New Zealand America Society] meeting- which is the same as the American AAS- in Brisbane, and I can't put a date on it, but you can identify it from the fact it was at Brisbane - could have been 1950. Dick Woolley, as he then was, gave the lead paper in Astronomy and Physics, which had been combined, the title of which was, "The Future of Astronomy." He went on for an hour, hour and a half, he made no mention of radio astronomy whatsoever. Bracewell happened to be in the audience and at the end there was no formal questions but at the end he went up to Dick Woolley very politely and in front of quite a number of people said, "Dr. Woolley, you talked about the future of astronomy and didn't once mention radio astronomy. Where do you think radio astronomy will be in 10 years time?" And he thought for about 30 seconds and said three words, "Oh, I think it will be forgotten." You'll get that from Bracewell. Don't write it up in quite that way, but that's true, absolutely true. So we had quite serious political difficulties in that sense. Now let me give the opposite. The boys down the line and particularly Cla [Clabon W.] Allen, who ended up at the University of London Observatory, were extremely helpful. And, of course, he was very knowledgeable on the Sun, so a lot of the development of ideas on the Sun went hand and glove between Pawsey and Allen.

Sullivan

Right, and it was actually a receiver set up at Mt. Stromlo, wasn't there?

Bowen

Oh yes. That was a bit of D. F. Martyn, that he wanted to get in on the act. Oh and Allen was interested in all the day to day changes, which we weren't doing. We weren't doing daily observations. He was interested in that. And of course D. F. Martyn had one thing to his credit, he got the first polarization of the Sun, of sunspot radiation.

Sullivan

What is your opinion, should he be credited in that paper where Pawsey gives the million degree result, there is an accompanying paper that Martyn wrote- should he be credited with giving the first good theoretical explanation of different depths and...

Bowen

Oh yes, sure. That was his, no doubt about it. But it came after the observations...

Sullivan

So there was both good and bad relations. But on the other hand with other radio astronomers there was virtually no contact, I think, with optical astronomers at this early stage.

Bowen

No, probably not.

Sullivan

So you were better off in that respect.

Bowen

The man we should mention is Harley Wood at the Sydney Observatory. He was very up to Bolton on identifications and positional astronomy.

Sullivan

I see, although he never took part in the publications.

Bowen

No, he was just somebody to consult with. He was sympathetic.

Sullivan

I should ask about your publications, of which I don't think they are many in radio astronomy in those early days. Was that because you were just spending all your time politicking?

Bowen

Yes and no. Let me be quite specific about this and please tone it down when you come to write about it. My history was I took my PhD at Kings College in London under Appleton in '34 or thereabouts. In '35 I went straight into the radar thing with [Robert] Watson-Watt. Let's skip the rest of the war. When I went out to Australia, D. F. Martyn had been head of the Division of Radiophysics. In all three cases there was one characteristic that stuck out a mile with [Edward] Appleton. Any work that was done by his students came out in the name of Appleton. And by way of commentary, Appleton is unique in that for all the work that was done over the years and he had some extremely good people working for him none of them ever got an FRS. This is for the record. Secondly, Watson-Watt unquestionably invented radar. There's no doubt about it. He is the man who invented air-warning radar. He then considered he invented everything that followed, including airborne radar which he had no connection with it whatever. In fact he didn't fly in a radar-equipped aircraft until about 1942. But he still considers he invented it.

Sullivan

So you say that the radar he invented was ground-to-air?

Bowen

Yes, air-warning. And that was done by other people, but certainly he produced the concept. And we come to D.F. Martyn. One of the most serious troubles that he ran into, there was a lab of some 150 people or something that he was trying to run that lab as if he personally did and was responsible for everything. This is something which- you get the picture. When I became Chief, I was going to be quite certain of one thing. That if any people did have any work they would get the credit for it. So let's say I was trying to be as helpful as I could all the way along the line, and I was not going to jump in and claim credit when somebody else did the work. The spectrograph was a case in point. I mean I can give you a dozen examples. So, if you can throw that in in the appropriate way. This is why my name was not... Well, let me also say that during that period, 1946 when our first publications started to appear- for the first year or year and a half I personally wrote damn near every paper that came out. They were an appalling lot of writers then, never seen such rubbish in all my life. Pawsey was particularly bad. And one paper of his in the IEE, the million degree paper, took two years to be published because of one reason. I finally quit, stopped rewriting it for him. He insisted on doing it certain ways which were bad. And it wouldn't get through the referee. Don't make too much of this. You remember the book we have on radar?

Sullivan

Yes, I see what you mean. That’s right.

Bowen

Each chapter was written by a different person. If you read through that book...

Sullivan

I haven’t.

Bowen

Well, dip into it. You have a look at the style that runs through that book and tell me who wrote it. A lot of preparation was done- figures and all the rest of it by those people. But my God, I wrote that book. So what I'm trying to say is that my previous experience of some pretty hard cases is that the best way to get first class work out of people is to give them the credit.

Sullivan

And apparently also you were not able to have the time to do any research of your own - just the effort to run the place.

Bowen

Right. It was 200-220 strong. We had a wide range of interests: radio astronomy, applied physics, things like surveying things like navigation work- took a lot of time. So I just wasn't in the picture.

Sullivan

Pawsey was the Chief of the Radio Astronomy section from the very beginning?

Bowen

Yes. He was head of that. The Parkes Telescope, of course, was different. I put a lot of my time into that. Not only fund raising, but design-wise. I put a lot of time into the design and into contractual arrangement.

Sullivan

Ok. Well, let’s go back before we get up to Parkes. I think you mentioned Bolton, and Wild’s early spectral. What would you say is the next outstanding thing?

Bowen

Oh, well I think that's it as far as the beginnings are concerned. Well, from there on it branched in so many fields I wouldn't really select any. Let me put it this way. By the middle ‘50s we had a pretty good run in the simple interferometry and the question of more complex arrays were coming out, of course, and that's where [Bernard Y.] Mills and [Wilbur Norman "Chris"] Christiansen came into the picture. Mills had a brainwave, of course- literally a brainwave. And invented the Mills Cross and I don't know whether you are familiar with the thinking at that time, but that was a real invention. Everybody knows about the linear array and also an east-west array giving a fan-beam at right angles to it. Similarly, if you crossed then and cross correlated the output, it is perfectly clear that if you had a sin wave signal coming in upon the intersection you could extract it from the noise. But it wasn’t clear that if it was random noise coming in, and you cross-correlated it would it affect your final beam? Does it or does it not? And of course, the only way to find this out was to try it and Mills built a 100 foot model, was it?

Sullivan

Right, he built a small model.

Bowen

A 100 foot array, and that was to test the principle.

Sullivan

I see. But whether a noise signal would...

Bowen

Yeah, by cross correlating you would in fact define a central beam.

Sullivan

No, that not clear from the papery either that that was the outstanding question, the Mills and Little paper.

Bowen

He skipped that, but before the event it wasn't at all clear. A lot of argument went on about that. And Mills established the principle with the small array. And meanwhile Christiansen was following along, with a shorter wavelength crosses in fact. So that was the significant development- well, '54, I think it was. But those thoughts were going around in '52 to '54, so the mid ‘50s up to the ‘60s were dominated by that kind of activity. Now the big antenna, the Parkes antenna- the concept of a big dish was, as a matter of fact, certainly 1950 - '49 even. To some extent it was indigenous- we thought this is the way to go but it was stimulated by the fact Lovell's beating this bandwagon in England. And it certainly looked very good idea to me. Frank Kerr was another one who backed it right from the jump. Now, there have been various controversial statements made from time to time that I was against the Christiansen efforts and Mills efforts, but this is completely wrong. I was the bloke who found the money so they could do it. I was backing them. But certainly by the late ‘50s - '59 or '60 - my own views were made up that there were real limitations as to what it could do- the Mills Cross. And the next step was particularly in relation to shorter wavelengths and the big dish was the answer. This gave the requisite resolution.

Sullivan

And by that time a choice had to be made, I understand?

Bowen

And a choice had to be made. Big money was involved- millions of dollars. And you just can't go around raising money of that kind without a very specific project in mind. So some choices had to be made. As far as the Division of Radiophysics was concerned the choice was clear cut. That we wanted an instrument which would for that kind of money would go on for 25 years or more. We'd still be a force in the radio astronomy field. And secondly, which could be used more or less simultaneously by a large number of people.

Sullivan

With some flexibility?

Bowen

Yeah. There were many good radio astronomers at that time and some of these proposals as they then existed - some of the Christiansen proposals, the Mills proposals were one man instruments. As a Laboratory, we couldn't afford to make it.

Sullivan

Well, I suppose one could say that the science had developed to the point where it wasn't the entrepreneur building his instrument rather had to serve...

Bowen

Now the group in that respect became important and that's the way they had to look at it. That particular argument took place in relation to the Parkes Telescope and the consensus at the end was that's the way to go and that's the way we went. Most people were pleased about this except for Mills and Christiansen. Anyhow they'd reached the top of the tree - this is another fact, thanks to my advocacy that had reach the top of the salary brackets and we couldn't pay them anymore. We had a lot of people pushing right against the top. So it was only natural that they move on and the University was a good place to go.

Sullivan

Well this is mentioned I think in Paul Wild's little story. He says it was top heavy basically and people went other places.

Bowen

Yes

Sullivan

While we're on this do you agree with Hey's recounting of this controversy?

Bowen

Very much so. He's got it pretty right. There's only one thing I seem to remember was a little bit off- I can't off the top of my head at the moment remember what it was. Well, continuing the story by the early ‘60s when the Parkes Telescope was in existence and starting to show its mettle, Paul's proposal for a heliograph which was the next big step, of course, was well in the mill, and well formulated and it came down to some second choices. What we call having completed the Parkes Telescope we could then think of the next step. And Paul's heliograph was still competitive with Mills Crosses and things like that. And again having the Parkes Telescope was logical thing for us to do was to go for an advanced instrument on the Sun. [?] and that led up to the next logical proposal which is still in the mill, of course, is the millimeter dish. We were going for something like a 75 - 100 foot dish.

Sullivan

Let me ask in particular the Parkes dish and the [?] array - maybe for others not that I know of anyway. It was largely American money that made them possible. Why - was the Australian Government - it seems like a marvelous record that CSIRO had put out...

Bowen

I think the answer is that time the amount of money- the amount of capital money that had gone into radio astronomy was very small. There was a lot of budget year by year money that went in to support that effort, naturally. It was quite a considerable sum. Amounting up to $.5 million or something. We were extremely lucky to get that backing. But what we couldn't get was capital sums, in addition. In fact, by comparison with UK or US we were badly off. So the only way to make progress was to explore.

End of Tape 30A

Sullivan Tape 30B

Sullivan

This is continuing with Taffy Bowen on 24 December ’73.

Bowen

So I find myself in a very lucky position. We started to explore the benevolent foundations. I found myself in a very lucky position vis-à-vis my wartime associates in the radar gang. I was good friends with Van [Vannevar] Bush who was Chairman of the of MIT, Karl Compton, president of MIT, and the chairman of what is called the Microwave Committee that spurred all that effort was Alfred Loomis.

Sullivan

Of the Radiation Lab, you mean?

Bowen

Yeah. That and the corresponding efforts was Alfred Loomis- I’m going to see him next week. He a multimillionaire, Wall Street lawyer, who has a history of supporting science. His grandfather had a laboratory, his father had a laboratory, he had a laboratory a Tuxedo Park and he used to support people like Wood - what's his initials? The optical man at Princeton, was it? R.B. Wood?

Sullivan

I don't know.

Bowen

Anyhow, a famous optical...

Sullivan

Astronomer?

Bowen

No, not an astronomer. Interferometers...

Sullivan

Optics?

Bowen

Yes. There's a classic university book by Wood. I think it’s R. W. Wood. He was interested in accurate time. Do you remember the [shot?] clocks?

Sullivan

No.

Bowen

I think there is one in the Smithsonian right now. But easily the most accurate clocks in the US in the ‘30s or maybe the late ‘20s. Gradually during the ‘30s quartz crystals took over from those clocks. He established those standards. So that is his interest in science. But he became interested in microwave radar was chairman of the NRC Microwave Committee. He was a Trustee of MIT, a Trustee of Caltech. At different times he was a Trustee of the Rockefeller Foundation, the Carnegie Corporation, and he knew the Ford people. When this question and every time I was in the States I talked to him, Van Bush and Merle Tuve here at DTM about the possibility of the big dish and how to get that kind of money and so on. And the first to come to the party were the Carnegie Corporation of which then Van Bush went back to be president and I forget whether he pointed it out or whether Loomis pointed it out that they had a $.25 million tucked away. Money which should have been paid out to a Commonwealth countries by edicts and so on. During the war what hadn’t been paid out...

Sullivan

At that point you were glad you were still a Commonwealth country.

Bowen

Right. So it took about a year, year and a half to do the ground work. That was the first grant we got and it was entirely- we knew it wasn't enough to build an antenna- but it was entirely gratuitous in the sense that we could do anything we liked with it, I mean, in the radio astronomy. We didn't have to build anything towards it. It didn't have to be matched, by our funds. But it was very, very benevolent.

Sullivan

Americans didn't have to observe on the telescope or anything like that?

Bowen

No. I think the only proviso, knowing that we had more money they didn't actually hand at all a quarter of a million dollars until we had something like the total sum which was the only proviso. In other words keep it in the bank and get the interest on it. Well, shortly after that I was put in touch with a Rockefeller of which Loomis, I think, was a Trustee at that time. But Warren Weaver was head of the Physical Sciences of the Rockefeller Foundation and he went back to the wartime days. He was particularly interested in anti-aircraft gunnery and the use of radar for that. So we had a very good friend there. And it wasn't long before we had $.25 million from Rockefeller. In that case he was quite canny and very forthright about it. He said, "Look there will be no announcement yet but you have this money but I can tell you you've got $.25 million provided you can get from the Australian Government an assurance that this sum will be matched 50-50 and any other sums." He knew about the Carnegie, of course. And I had the simple task of going back to Australia and well, first getting the assurance, which I got from the then Chairman of CSIRO. He said, "I'll go and see the Minister this afternoon." He didn't go and see the Minister he went to see the Prime Minister called [?] and he got the assurance the next day.

Sullivan

When was this?

Bowen

About '56.

Sullivan

That early?

Bowen

Oh yes. I think the Carnegie grant was '55. This was around about '56 or '57.

Sullivan

This was 5 or 6 years before the telescope appeared?

Bowen

Oh yes.

Sullivan

Because you didn't have the final designs or anything for the telescope?

Bowen

No, we had pretty good idea what it was going to look like. But we didn't have an engineering design. So the first step and this was well understood by Carnegie and Rockefeller. First thing we'd do is to get a design study - we had Freeman Fox lined up in London to do it. And they spent 3 years but we had to have the assurance and nearly all the money before we started the design study. You'll find it in some of those papers that I wrote about the origins of the Parkes Telescope - the dates of which we placed contact with Freeman Fox but it's about '56 or '57. And we placed a contract then with [?] for construction in July '58 or '59. I remember it as the month of July, I was off in Germany doing it [?] and appeared to have the most competence as it turned out [?]. And they did a wonderful job for us. So it was 2 or 3 years generating interest and finding the money, 3 years design time and it took 2.5 years to build.

Sullivan

And the building went rather smoothly compared to many other big dish projects.

Bowen

Very smoothly. There were no delays. We actually had a 21 months - no, I forget. Roughly 2 year-completion time and we had a penalty clause on them. And they actually missed a completion time by 3 months. But we didn't impose the penalty- they did so well. No hitches of any description.

Sullivan

What is the relation between this dish and the very similar Goldstone dish?

Bowen

We gave them all the engineering designs to NASA. We worked very closely with them on that. At one stage we almost got feeling foxy as consultants but there was a contractual hitch as between the US and Great Britain so that didn't come off. But we were very close and I might say I think we got about $.25 million.

Sullivan

I see, that's a useful by-product.

Bowen

In grants which we finally used to reskin the...

Sullivan

Oh that's 2 or 3 years ago, the resurfacing.

Bowen

Yes, reskinned to the tripod lens. It was good for 2 cm. That was done with NASA money. The interesting thing - NASA gave us that money to do engineering studies on this dish which would be fed back into NASA. I think we the [?] characteristics [?] but particularly to do studies of the methods of measuring accurately, this kind of service. So all that work going on with theodolites and so on was in effect paid for by NASA. And we had enough money [?]

Sullivan

Let me ask a more general question. It's not clear to me, exactly why Australia and England led the way in radio astronomy for 10 or 15 years and the US lagged so much behind when almost all of the sciences the US largely because of the size is way ahead. Do you have any ideas?

Bowen

I can't really answer that. The reasons why Australia and the UK were in that because it was quite clear - it came straight out of the radar business.

Sullivan

Right, but then why not the US?

Bowen

Why the US didn't pick it up I just cannot understand. I've never understood it. And I think I can only rationalize it by saying that there was such a tremendous effort on nuclear work and thereafter nuclear work in the US. That that absorbed some of the best people. This was some of the best people who had been involved in the radar thing in the US. Now this was true not of the United Kingdom or Australia.

Sullivan

And the Radiation Lab didn't exist after the war, of course. It was split up.

Bowen

Yes. Well, all of us people went back to their habitats as it were. And all appeared to be completely absorbed.

Sullivan

Although, of course, that happened in England and yet I guess it's largely a matter of...

Bowen

It was just the two - well, Hey didn't carry on conspicuously, I mean he was too much absorbed in- this is a good example. You see the man didn't get as deeply involved as he might have after the war.

Sullivan

Yeah, it was only about 2 years and then apparently he...

Bowen

And whereas Lovell and Ryle both were in positions at Manchester and Cambridge where they could follow up. So it's not a very satisfactory answer but...

Sullivan

Right. But I'm saying even if there had been someone with Ryle's temperament at the Radiation Lab he could have gone back and started his own effort.

Bowen

Oh yes. Dicke presumably.

Sullivan

Yeah, right. If he'd focused on radio astronomy he might have been such a person.

Bowen

Well, you can almost name them. There's Dicke who is probably the most conspicuous example. Lawson was another one. Do you remember him?

Sullivan

No.

Bowen

Lawson. He did an awful lot of antenna work and front end noise temperatures. He was at that end of the piece and was a receiver man. But he went with GE to their the nuclear research labs. Well, that put him out of the running. It could have been Louis [?] but he went to Los Alamos. These are the kinds of people who could have done it.

Sullivan

Or Southworth?

Bowen

Well, no, I think the Bell Lab would always be [?] the reason that Jansky was. But they could do these things as a sideline but they couldn't...

Sullivan

Major efforts. Unless you can think of some other comments you like to make I think that covers it very much.

Bowen

Yes, well I've skipped the latter part of this - it's all pretty much in the literature and well covered.

Sullivan

It's the early part that's of particular interest. Thank you very much. That ends the interview with Taffy Bowen on 23 December ’73 at the Australian Embassy in Washington.

Modified on Wednesday, 20-Mar-2013 15:02:10 EDT by Ellen Bouton, Archivist (Questions or feedback)