[Covington, 1983]
Arthue E. Covington, 1983. (NRAO/AUI/NSF image)



NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with Arthur E. Covington
At AAS meeting, Haverford, PA
23 June 1976
Interview time: 112 minutes
Transcribed for Sullivan in 1977 by Bonnie Jacobs, transcription corrected and edited by Ellen Bouton in 2016.

Note: The interview listed below was conducted as part of Sullivan's research for his book, Cosmic Noise: A History of Early Radio Astronomy (Cambridge University Press, 2009) and was transcribed for the NRAO Archives by Sierra E. Smith in 2015. The transcript was reviewed and edited/corrected by Ellen N. Bouton in 2016. Any notes of correction or clarification added in the 2016 reviewing/editing process have been included in brackets. During processing, full names of institutions and people were added in brackets when they first appear. Places where we are uncertain about what was said are indicated with parentheses and question mark (?). If researchers are able to suggest correct text, please contact the Archivist. Sullivan's notes about each interview are available on Sullivan's interviewee Web page. We are grateful for the 2011 Herbert C. Pollock Award from Dudley Observatory which funded digitization of Sullivan's original cassette tapes.

Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons, including subsequent experiences, interactions with others, and one's feelings about an event.

Click for Part 1 of the 1976 Covington interview

Click start to listen to the audio for part 2 of the 1976 interview.

Begin Tape 47B

Sullivan

This is continuing with Arthur Covington on 23rd June í76. So now when did the daily monitoring program actually begin?

Covington

In February, sometime, of 1947.

Sullivan

And has been continuous until Ė itís still going?

Covington

Itís still going. And itís even multiplied to two stations. One in Lake Traverse, Ontario, and the other in Penticton, British Columbia.

Sullivan

When did that happen?

Covington

The Penticton station occurred in 1964. The ARO station in 1962. In the solar patrol, observations were, of course, taken at the radio field station in í47 as Iíve mentioned. And we were surrounded by radar developments so that was a real nuisance. I can recall running around the radio field station just asking who had various transmitters on. So in about a yearís time we established a Goth Hill Radio Observatory, about 5 miles away from the radio field station. And that was Ė Goth Hill was in existence from 1947 to 1962. Goth Hill Observatory, in turn, became polluted with radar interference from the Ottawa Airport and that led to the establishment of the Algonquin Radio Observatory, ARO, at Lake Traverse.

Sullivan

All these years, how many days did you miss per year specifically?

Covington

Oh, at first we took Saturdays and Sundays off Ė a matter of convenience.

Sullivan

It was not automated then, either?

Covington

No, it wasnít. But in about two yearsí time we began to see the gaps were significant and then made arrangements to continue Saturdays and Sundays. But the real program of continuous observations didnít start until the IGY [International Geophysical Year] in 1957.

Sullivan

What do you mean by ďthe real program?Ē What was the difference before and after?

Covington

The solar program Iíve just taken as incidental. There was always a need to develop new equipment. After the solar patrol was established, we tried a number of experiments Ė I canít recall which came first. But one of them was to build a high resolution Ė a big antenna to get high resolution so that we could pick out sunspots. Well, we went through various stages and finally ended up with a slotted waveguide array 150 feet long. That was in operation around 1950 or so.

Sullivan

1950? Now it was first described here in í54, I think, in an article with Covington and Broten in Ap. J. [2016 note: Covington, A.E., Broten, N.W. Brightness of the Solar Disk at a Wave Length of 10.3 Centimeters. Ap. J. 119: 569, 1954]

Covington

Thatís right. I guess the construction started in 1950, finished in í52, and wrote the paper in í54. So thatís a four year undertaking.

Sullivan

And what was the purpose, now? What was your goal to do with this?

Covington

This was to study the radio emission from individual radio sunspots.

Sullivan

Right. And you had a fan beam, I guess?

Covington

Yes, the fan beam as I recall was about 8 minutes east-west and 10 degrees north-south. The slotted waveguide array is probably the longest thatís ever been made.

Sullivan

For any purpose?

Covington

Any purpose.

Sullivan

How did you come upon that? I donít think anyone else in radio astronomy has made a slotted waveguide array either. Is that true?

Covington

I think itís not true. I think maybe Swarup has one in India. And the people in Illinois had one. I think Vermilion?

Sullivan

What was that used for?

Covington

Cosmic noise, the Galactic sources.

Sullivan

Really? Before [George W.] Swenson?

Covington

Swenson, yes.

Sullivan

Before they got the big dish, I mean the big hole in the ground.

Covington

Swenson had a parabolic cylinder in the ground where the line feeds were along the top, referring to the line feed Ė

Sullivan

Oh, the line feed. So that was a feed in that case rather than the actual antenna.

Covington

Well, weíre getting into whatís an antenna.

Sullivan

Well, before we get on that, though, when I was asking how many days were missed I meant just due to electronics failure or something like this. Iím just curious as to how perfect the record is of a flux value at 10.7 cm on each day.

Covington

There came a time when I realized that if the service was to be maintained it would be wise to have duplicate apparatus. So quite early we duplicated everything that we built. And, of course, itís easier to keep two sets going than one.

Sullivan

Do you have any feel, though, for how many Ė still, there must be a couple of days that got missed for one reason or another.

Covington

Well after í57 I think the records are pretty continuous. The technical staff, of course, worked Saturdays and Sundays and arrangements had to be made to compensate them one way or another.

Sullivan

What was the change in the program before and after the IGY?

Covington

After the IGY the solar radio emission was then really accepted as a measure of solar activity. And we started sending our daily flux values to the World Network [World Data Center for Solar Terrestrial Physics], in North America the headquarters were centered in Boulder, Colorado. With this sort of service, outside service, the feeling is somebody depends on you so you take a slightly different attitude towards your work. Prior to that I know I was more interested in building big antennas, improving receiver quality.

Sullivan

So youíre saying that the monitoring for the 10 years, í47 to í57, was really just something always going on the side and your main activity was in thinking about building new antennas of high resolution and so forth.

Covington

Thatís right. In time Ė Another factor occurred from about í47 to í56. The National Research Council Observatory was the only one operating in Canada. The Dominion Observatory as the senior observatory, a tremendous intense tradition and they became interested quite seriously in wanting to get into radio astronomy. Then there was some need to cooperate. It was quite a difficult period. I donít quite know how to describe it.

Sullivan

As to how exactly to bring this about, you mean?

Covington

I think, in the case of the National Research Council, the long array which we were using was first 150 feet and them we made it into a compound interferometer by adding two outside dishes and it was 300 feet. At that stage there was the question of whether to make a north-south extension or still to go further east-west. At this time the Dominion Observatory indicated that they wanted to become involved in radio astronomy and a series of meetings occurred between the two institutions, and it was decided to commence a site survey throughout Canada. This was where, in our particular case, Nick [? Pattinson?] got together some radio equipment in a lorry, sensitive receivers, and a number of sites were tested.

Sullivan

What year was this?

Covington

This is í56, late í56. The actual field observations were made in í57. The Dominion Observatory under Jack Locke first used the equipment. They went to Green Bank. Itís rather interesting, I think they took the first radio observations at Green Bank with this portable equipment. This was en route to California. Whether or not they stopped off at John Boltonís site at Owens Valley I donít know. But then they went on to British Columbia, and British Columbia, of course, examined in more detail a number of sites.

Sullivan

What was the purpose of going to Green Bank?

Covington

If I remember correctly, Jansky and Bailey had made a site survey for a national observatory in the United States and they wanted to use that site to sort of get a comparative calibration.

Sullivan

They werenít thinking of putting the Canadian observatory in Green Bank. [Laughter.]

Covington

Well, we often joked about it. [Laughter.]

Sullivan

You were not directly involved.

Covington

No, I wasnít. At that time I was quite committed in the IGY program so this would be in í57 and IGY was going in full swing.

Sullivan

What were you doing especially for the IGY?

Covington

There was Ė making sure the daily flux measurements were made and sent out on this international network. And then we further introduced the practice of looking at outbursts and describing them in terms of type, telling when they commenced, their peak flux, and so on.

Sullivan

I should first ask, the daily monitoring Ė this was a single new time value?

Covington

The daily monitoring Ė by this time the equipment had some automatic features so the antenna would start tracking at sunrise and continue until sunset without any person being present. The actual determination of the sensitivity required somebody being present.

Sullivan

Putting a noise tube on or something?

Covington

Putting the black box around the dipole to measure ambient temperature and pointing the antenna towards the zenith.

Sullivan

And that black box was used all the way up until the IGY, youíre saying?

Covington

Yes, and even now the black box is being replaced by a more convenient waveguide termination. We call it a flap attenuator. Weíre using a standard s-band waveguide, thatís three inches by one and a half, and thereís a long flap piece of Bakelite covered with carbon which flips in and it ii the (?) black box. This has proven very reliable. I have quoted and still stand by it that the relative accuracy over this period of time, except for the first six months, is about 2.5 percent. And more recently when weíve had the two observatories going, i.e. ARO and DRAO, Iíd say the relative accuracy could be half a percent.

Sullivan

There was another article in the special issue of Proc. IRE in í58 with Medd [2016 note: Medd, W.J., Covington, A.E. Discussion of 10.7-CM Solar Radio Flux Measurements and an Estimation of the Accuracy of Observations. Proc. IRE 46: 112, 1958] in which you say the earliest fluxes were good to plus or minus 10 percent. And when did they become more accurate?

Covington

After about six months or so, late í47.

Sullivan

And what was the measurement at that time? That was not tracking all day long, was it?

Covington

No. We would come out to the lab about 9:00 or so, and weíd start the instruments going.

Sullivan

And youíd take a mean of the entire dayís Ė ?

Covington

Oh, no. The 10 cm emission is quite constant compared to the metric wave emission. Usually one calibration per day is satisfactory. Of course we had to test this. I remember spending a week or two taking observations every hour during the day and seeing that they were pretty constant and realizing one would be sufficient.

Sullivan

The monitoring was only for solar activity then?

Covington

Yes.

Sullivan

I mean the daily tracking was only for activity. OK, letís look at some of these other papers that havenít been mentioned. Proceedings of the IRE in 1949 [2016 note: Covington, A.E. Circularly Polarized Solar Radiation in 10.7 Centimeters. Proc. IRE 37: 407, 1949] you say that the quiet sun has no polarization but sunspots have circular polarization. This is apparently a large quarter wave plate that you Ė Can you tell me about that?

Covington

Oh, nothing much other than itís a direct analog taken from optical physics.

Sullivan

I think that was the first time that anyone in radio astronomy had done that. Well, maybe Ryle about that time.

Covington

No, I think it would be the first or second. You should look and check and see what Ryle did. He might have used an interferometer with crossed dipoles.

Sullivan

Thatís what he did, yes.

Covington

And I think that came slightly before but Ė

Sullivan

Oh yes. He detected the circular polarization before, but Iím thinking of the quarter wave plate over the antenna was sort of unusual.

Covington

Oh yes, that would be, I think.

Sullivan

He had that in í46, that circular polarization. And Hey and Appleton also had circular polarization in í46. In fact there was a third paper Ė that must be the Australians because thatís all thatís left Ė they were all together in Nature within two weeks. Now here Covington and Medd in í49 of the Journal of the RASC on simultaneous observations of eight events at 1.5 meters as well as the 10.7 cm. [2016 note: Covington, A.E., Medd, W.J. Simultaneous Observations of Solar Radio Noise on 1.5 Meters and 10.7 Centimeters. JRASC 43: 106, 1949] Did you set these meter wavelength observations up yourself?

Covington

Well, I was curious to see what the metric wavelengths profile looked like in comparison to the 10 cm. Actually having actual observations in my own hands. Wilf [Wilford Medd] was the first engineer who was working with me. It was one of his first projects. We looked at those simultaneous profiles and I know I realized that an entirely different nature indicated that the 10 cm emission came from one level and the metric from another. And there would be such a wealth of detail in these two regions that it would be wise for me not to pursue the metric wavelength. SO I more or less bowed out of the metric wavelength.

Sullivan

So you decided to stick to microwave. Now what about this Journal of the RASC in í53 where you talk about the diminution of the 10.7 cm flux after a flare in May í51. [2016 note: Covington, A. E.; Dodson, Helen W. Absorption of 10.7-centimetre Solar Radiation during Flare of May 19, 1951. JRASC 47: 207, 1953] And you were wondering according to the abstract whether the flocculi might be doing some absorbing. Has this phenomenon been confirmed since?

Covington

Itís quite a rare event but itís been confirmed. Weíve confirmed it. The Japanese confirmed it after us. The Germans, [Otto] Hachenberg, Heinrich Hertz Institute, confirmed it. Itís relatively rare.

Sullivan

What are the conditions that are necessary, does it seem?

Covington

It seemed as though the flare occurrs, itís a brightening of a certain level and then later on some dark clouds are ejected and they lie over this bright plage and theyíre dense, cooler, and thereby it cut off the more intense emission from the underlying area. Just an illustration of the complexity of a flare event.

Sullivan

In other words, the plasma frequency becomes so high as to not to let the 10.7 cm through?

Covington

Yes, thatís one way of putting it.

Sullivan

Youíre talking about the microwave flux goes down, the Hα flux does not diminish too, does it?

Covington

Yes, in the May event it did diminish. In fact, thatís how you can detect that the dark clouds lie over the Ė

Sullivan

When you say dark you really do mean that.

Covington

They are dark, yes, in this case.

Sullivan

It looks like the first time that you teamed up with some optical astronomers to do some interpretation was in í53 when you gave a talk at the AAS with [Helen W.] Dodson and [E. Ruth] Hedeman Ė you talked about the percentage of Hα events with respect to the percentage of radio events and the flare importances, so forth. Is this the first time you had collaborated with them?

Covington

Yes, it was the first time I had collaborated with optical astronomers of that nature. Helen Dodson and Ruth Hedeman are from the McMath-Hulbert Observatory. Previous to that they had collaborated with Cornell University Ė [Charles L.] Seeger and [Charles E.] Burrows. And theyíd sort of exhausted that particular study. And then they became aware of our 10 cm work. And they discussed the whole possibility of coming to Ottawa with Dr. [Robert R.] McMath, and, of course, got his blessing and I was told he was sort of skeptical of radio astronomy. I recall he said, ďMake sure those bumps are genuine.Ē [Laughter.]

So I think it was in February Helen and Ruth came, and I recall meeting them at the hotel. They had two suitcases chock full of optical pictures. And I took them out to the radio field station and sort of set things down. One of the first questions Helen asked me was, ďWhat did you see on May 19, 1951?Ē And she had observed this darkening of the Hα with the dark cloud lying over the bright plage . So we looked at the radio records and there was the diminution. Up to then I had been aware of the reduction of the radio waves, but being so unusual I was skeptical and didnít know what to make of it. You see, you just have an isolated event Ė . I happened to be at the observatory when that was occurring, and fortunately I checked all the equipment and satisfied myself that everything was normal. I was willing to stand by it as it being a good observation.

Sullivan

Iím interested in this because this is one of the earliest examples of a direct joint collaboration between optical and radio astronomers.

Covington

I hadnít realized that.

Sullivan

Well, if youíll think about it, there really wasnít very much, because the optical astronomers were very skeptical. They did not understand the radio technology and so forth.

Covington

McMathís statement, ďMake sure those bumps are genuine.Ē Thatís all he regarded them as, bumps. [Laughter.]

Sullivan

But apparently Helen Dodson, anyway, believed that this was a very useful science, and so forth.

Covington

Yes, she was quite helpful and I appreciate her understanding from the optical side.

Sullivan

She came to you rather than Ė You did not go out seeking?

Covington

Thatís right. It was through McMath. I think Helen approached McMath, of course. And [Edith] Müller is involved in this, the McMath end, as well.

Sullivan

You had an NRC report in í55 in which you talk about information that can be derived about atmospheric defraction and absorption from low elevation observations which I suppose was just something that you decided. [2016 note: Covington, A.E. Notes on Low Angle Reception of Solar Radio Emission, λ = 10.7 cm. NRC ERB-368, December 1955.] Was this a special program?

Covington

The background of that is interesting. It goes back to the radar aspect. There was a Bill Brown, who was in charge of the radar program, and he saw the radio telescope on top of the building and how it was following the sun. Now he had the task of calibrating boresight of the radar antenna. And he decided that he would use the sun, immediate position of the sun from the almanac. I think as early as í47, no, it would be a bit later Ė í48 or í49, he was using the sun to calibrate the boresight of an MHF, microwave [high?] finder. And it was quite successful. Well then time went on, a few years, and this was picked up by the Canadian Army. They wanted to know more about the whole radio phenomena of a setting sun. And in response to their request, I wrote and prepared that internal report.

Sullivan

Did this involve special observations?

Covington

Not particularly.

Sullivan

It was things that you already know.

Covington

And it was very practical because the Canadian Air Force was at numerous stations throughout Canada and they had to check the boresight of all these antennas and this was about the only convenient and reliable way it could be done. I think now itís very common practice for certain antennas.

Sullivan

What about the 1955 eclipse which you have a paper with Medd, [Gladys] Harvey and [Norman] Broten? [2016 note: Covington, A. E.; Medd, W. J.; Harvey, G. A.; Broten, N. W. Radio Brightness Distribution of the Sun at a Wave-length of 10.7 Centimetres, June 30, 1954. JRASC 49: 235, 1955] Can you tell me the story about that?

Covington

Oh, that was more or less prepared. We knew it well in advance.

Sullivan

Was that in Ottawa?

Covington

In Ottawa. It was a partial eclipse.

Sullivan

Youíve never gone on any expeditions to eclipses?

Covington

Yes, we did that in 1963 to a place in Quebec, the Province of Quebec.

Sullivan

Now you said that Medd was your first engineer. Was the group working with you growing during this time or was it always staying -- ?

Covington

Oh, I mentioned the exodus of engineers from the Council [National Research Council] into school into the atomic energy program. Well, I then required two technicians. So they were working with me for a while. Then Medd came. It was growing and then Broten came. He came first as a summer student and majored as an engineer. Then Gladys Harvey. We had (Zotov?). No, not (Zotov?, Markoff?) He only stayed a year or two. And by 1954 and í55 we were quite a small group, four professionals and three or four technicians. At one time, I guess itís worthwhile to mention, during the Korean affair, Medd was assigned to some radar development and the NRC nearly closed down the radio astronomy. I had a stubborn streak and refused to move, so we hung on. But after that it grew some more.

Sullivan

But there was no other radio astronomy until Penticton got going in Canada, is this correct?

Covington

Pretty well. There was a group over in Defense Research Board, Ted Hartz. Iím not quite sure what he started.

Sullivan

What did he do?

Covington

He was monitoring the scintillations from Cassiopeia and the absorptions of cosmic noise due to the SID effect.

Sullivan

H-A-R-T-Z?

Covington

H-A-R-T-Z.

Sullivan

I donít know his name. And this was about what time?

Covington

í54 to í55. Ted Hartz, in the history of radio astronomy, I think stands out and should be checked Ė Canadians had the Alouette satellite and they took some of the first radio astronomy observations from the satellite.

Sullivan

When was that satellite sent up? Roughly, once again.

Covington

í65? I should know.

Sullivan

Mid-Ď60s sometime.

Covington

Yes, mid-Ď60s.

Sullivan

OK, Iíll check into that.

Covington

Yes, I would check that. Itís a significant observation. I remember being at meetings discussing the whole thing.

Sullivan

Well, we got sidetracked from talking about your Proceedings of the IRE in 1948 paper in which you established the 27 day periodicity. [2016 note: Covington, A.E. Solar Noise Observations on 10.7 Centimeters. Proc. IRE 36: 454, 1948.] This must have been quite exciting to find this, that the monitoring was really worthwhile and so forth. In terms of showing something. Were you learning a lot about the standard solar astronomy all this time in the process, or were you just Ė Iím trying to get at how you went about trying to interpret all this.

Covington

At that period I remember [Joseph L.] Pawsey came through. Iíve been trying to place this visit. You said it was í47 Ė I guess we learned our astronomy in sort of an amateurish way. We were really more interested in radio technology. Joe Pawsey, of course, was an ionosphere man and he and the Australian groups had pretty well set the theory. As a radio engineer you sort of pick up these things quickly and you donít worry too much about them. So I think I wasnít too excited about the Ė

Sullivan

Well, what really did turn you on then as a result.

Covington

The building of the big antenna. Getting after high resolution.

Sullivan

But you must have had great dedication, though, to keep this monitoring going. That doesnít mean itís exciting, of course. Itís just sort of a service, is that the way you were looking at it?

Covington

Yes, the dedication came much later. The solar patrol even in the group it was something you do. [Laughter.] Like keeping house. Looking back now I wish weíd been a little bit tidy.

Sullivan

Well could you summarize briefly what you feel Ė itís been almost 30 years now of monitoring, what that monitoring has mainly shown in terms of solar physics?

Covington

One thing, I hope and I think will happen, is it will provide a very precise measure of solar x-ray ultraviolet emission. And if the technology were pushed a little bit you can get down to a tenth of a percent accuracy. And this is far more than any optical observatory can do. Well, the satellite observatory. And even though some people donít like saying itís the next decimal place but when you look back over the history of science, the next decimal place is usually many times. The discovery of argon and so on. The work Iíve done I think can be summarized in perhaps three areas: the provision of this index, which is pretty well recognized. I was also puzzled over the burst profiles, the dynamics of flares. Yes, youíre bringing back memories. I can remember spending months looking at these burst profiles and thinking of mechanisms, how regions can decay. Not very profound, but they intrigued me.

Sullivan

I donít think you published very much along these lines, did you?

Covington

Well, yes. There was an international symposium in Paris in 1958. And thereís a paper in there. [2016 note: Covington, A.E. The solar emission at 10-cm wavelength. IAU Symp. 9: 159, 1959] That paper was produced under great stress and very quickly Ė in two weeks, I think. In less than two weeks I produced it. And somebody has referred to it as a classic. [Laughter.] I was surprised.

Sullivan

But in the Journal of the RASC in í58, also, you talk about there are two basic types of flares: thermal and nonthermal.

Covington

Yes.

Sullivan

And this must have come from studying the burst profiles also?

Covington

Yes. That intrigued me more than the solar patrol nature. And, of course, the development of high resolution antennas that led to the compound interferometer.

Sullivan

You havenít told me about actually building the compound interferometer.

Covington

Oh, I think that would be another stage. [Laughter.]

Sullivan

That was in the mid-50s?

Covington

í54, after í54. In í54 I made a trip to England and the continent. It was to attend the URSI General Assembly at The Hague, and there I realized that Lovellís big dish was about to be completed and that if we could do something with our slotted waveguide array and using the strong source as the sun, we could probably get some high resolution that Lovell couldnít get. And so that was part of the realization of the creation of the compound interferometer.

Sullivan

I see. Although he in fact never did any solar work with that dish.

Covington

No.

Sullivan

But you didnít know that at the time?

Covington

I was just more anxious in getting the resolution.

Sullivan

What came out of the compound interferometer in its extension? Did this high resolution pay off?

Covington

Yes. At the Algonquin Radio Observatory we now have a 32-element array which is 600 feet long and produces a fanned beam of 1.5 minutes of arc and we are now taking daily transits of the sun.

Sullivan

I see. Thirty-two small dishes?

Covington

Thirty-two dishes in a row.

Sullivan

Well, what about these in the Ď50s, these compound interferometers. What did they tell you about the nature of the burst in active regions and so forth?

Covington

Well, it gave us the equivalent temperature of the sunspot which more or less verified the eclipse observations, and the east-west dimensions, a few minutes of arc. Again, that more or less verified the eclipse observations. We did notice that on the edge, on the limb of the sun the radio spots were point-like so this would imply that the emitting surface was a plate-like structure that lay on the solar surface.

Sullivan

I notice that back in 1960 you have a paper in the Bulletin of the Radio Electronic Engineering Division of NRC, Covington, Legg, and Wong proposed an array of 10 foot dishes for Algonquin which I guess is what you just described.

Covington

Yes.

Sullivan

Itís grown out of that. This is 1960, however. When did this finally get built?

Covington

That was when the idea was conceived and it was finished in í66. So that was a six year program. There are actually four stages proposed in that antenna and we only finished two of them. We were running short of manpower and money so the full potential of the ideas are not available. Itís interesting to realize that the Japanese, the University of Nagoya, [Haruo] Tanaka, have picked up this idea and they have really exploited it. The final step is to connect a computer to the antenna and data process the information, taking out various errors, and produce a map of the sun.

Sullivan

A daily map of the sun?

Covington

Yeah. But we have a two-dimensional map of the sun.

Sullivan

Well but now, how would this be superior to Bracewellís array? Is this not similar?

Covington

Itís quite similar. The Japanese are using a T. Bracewell has a cross. The compound interferometer eliminates some of the redundancy and makes use of Ė trades that off to gain resolution. When you reduce Ė eliminate the redundancy then you have to desirably use a computer to process the information to have everything absolutely perfect. And thereís no redundancy. Things have to be perfect.

Sullivan

Right, everything counts. One final thing. We havenít talked too much about your work, well somewhat, about your work relative to other solar work going on. Other monitoring programs and so forth. When was the first other additional monitoring program? Until the IGY, was that the first time?

Covington

Yes, I think the IGY brought in many observatories. And after three or four years they sort of dropped out and got into other areas of activity. I guess I was left holding the bag. [Laughter.]

Sullivan

But you were the only one before then that was doing microwave monitoring?

Covington

Well, the Naval Research Lab commenced 3 cm work first. Then later extended it to millimeter work.

Sullivan

Right. But they never really monitored Ė

Covington

Yes, they monitored the sun. I can recall inter-comparing our 10 cm records with their 3 cm records. This was through Fred Haddock. I think they never really published anything. Itís a good case, you know, many institutions have a backlog of good ideas which have never been published. More recently the Air Force at Cambridge picked up the solar monitoring and they are carrying it to a number of frequencies.

Sullivan

Thatís quite recent though Ė the last five years or something like that?

Covington

í65. í66 I think.

Sullivan

Well I think that pretty well covers what I wanted to talk about unless you can think of some comments that havenít been touched upon.

Covington

I realize looking back now there have been a lot of ramblings, sort of free associations and any one of these could lead to further interesting stories.

Sullivan

When was the first time that you actually Ė well the first time you talked with the optical astronomers was with Helen Dodson, apparently. Well, thatís right after you did that solar eclipse.

Covington

Lurie. And then the second time would be Helen Dodson.

Sullivan

But it was even after that, before you were presenting your results to astronomers at astronomersí meetings. You were usually going to URSI meetings and things like this.

Covington

Well thatís quite true. Itís interesting that after the War the URSI meeting, the spring URSI meeting was held in Washington. This would be í47. And at the meeting I can recall speaking to Reber and Jansky, quite a thrill looking back. Jansky, of course, at that time was not working in radio astronomy but was working on receivers, I think, or something.

Sullivan

Low noise receivers, yeah.

Covington

But he came down to the meeting and he read an abstract and he wanted to see what was going on. Other people I met at that meeting was John Hagen, Haddock from NRL, Alan Shapley of Central Bureau of Propagation [Central Radio Propagation Laboratory, National Bureau of Standards]. He was concerned with providing a warning service for radio circuits. There was another person, J.F. [Jean François] Denisse from France. He was theoretically inclined, and I know he picked up my observations and made extensive use of them.

Sullivan

Right, he had a big thesis, in í48 or so.

Covington

Yes, in fact I think it would be the first thesis in radio astronomy.

Sullivan

It well might be.

Covington

And the people at NRL [Naval Research Laboratory] translated it.

Sullivan

Yes, thatís right. Iíve seen that translation. Is there any point where you can sort of say, ďWell, at that time I began talking to astronomers more than I did to radio engineers?Ē Does this strike you as a valid question at all?

Covington

Iíve been pretty well more with radio engineers than astronomers. The galactic astronomers are way out there.

Sullivan

Well, thank you very much. That ends the interview with Arthur Covington on 23rd June 1976.

End Tape 47B

Click for Part 1 of the 1976 Covington interview

Modified on Wednesday, 08-Jun-2016 14:57:39 EDT by Ellen Bouton, Archivist (Questions or feedback)