Oral History Transcript — Dr. William C. Livingston
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William C. Livingston; August 22, 2009
ABSTRACT: In this interview William Livingston discusses topics such as: his time and work in astronomy at the Kitt Peak National Observatory and National Solar Observatory; working for Keith Pierce at Mount Wilson Observatory doing infrared work; doing his graduate work at the University of California, Berkeley; meeting Otto Struve; working with Gerald Kron at Lick Observatory; solar telescopes; Leo Goldberg; vacuum solar telescopes; collaborating with Dick White at the High Altitude Observatory; discovering water on the sun; the evolution and uses of Kitt Peak.
Leslie:This is Bill Leslie from Johns Hopkins University and Iím interviewing Dr. William Livingston, who has spent more than four decades at the Kitt Peak National Observatory and who is currently astronomer emeritus at the National Solar Observatory. Today is Saturday, August 22, and weíre at the McMath-Pierce Solar Telescope at Kitt Peak, Arizona. I guess weíll begin with your early education and your early career in astronomy and how you got interested in this particular field.
Livingston: My astronomy career began with Keith Pierce. My first real job was working for Keith Pierce at Mount Wilson in California. Keith had come out from Michigan to use the Snow Telescope and do infrared work. I wasnít specifically to work with Keith, but he came out and we worked together there at that telescope. Eventually he left and did other things at the Snow and I eventually went on to graduate school at Berkeley.
Leslie:So you met him very early on.
Livingston: Very early on.
Leslie:How did you get a job out at the Snow Telescope? You werenít even finished as an undergrad yet at that point, right?
Livingston: On finishing high school, I thought, ďWell, now I have to go get a job. What shall I do?Ē I lived in Los Angeles, and my chums and I had climbed Mount Wilson which is above Pasadena. ďThere is an observatory there and Iíll go apply.Ē I lived near USC, in south LA. I took the V car downtown, took the interurban Red Car to Pasadena and then walked the mile or so up to 813 Santa Barbara Street. Itís a famous address.
Leslie:Whose address is it?
Livingston: Mount Wilson Observatory.
Leslie:Thatís its address. Okay.
Itís always been 813 Santa Barbara Street. It goes back to Hale. Anyway, I went in and said Iíd like a job. They could have just laughed. Hereís a kid, maybe, 16 or 17? The receptionist said, ďWell, what can you do.Ē Then one of the other ladies, a secretary, Mrs. McConnell, came in. She also asked, ďWhat can you do?Ē I said, ďWell, I built a telescope, for example.Ē
Leslie:Tell me a bit about that. Thatís interesting.
Livingston: As you know, amateurs built telescopes. In fact I hadnít really built one; Iíd merely thought about it. I belonged to something called the LA Astronomical Society, which was located downtown in Los Angeles. They had a little shop with a lathe, and there was a group of people to help youngsters and others build telescopes. They also had speakers perhaps once a month. Anyway, with that lead in, I had decided that Iíd like to go to work at an observatory. The secretary was not too impressed with my telescope building, as you might have guessed. She asked, ďDo you do anything else?Ē ďWell, Iíve had drafting. I do drafting.Ē Ah, that seemed to have some effect. They said, ďLet me take you in to this gentleman who is the head of the drafting department.Ē He immediately took me into another building where I was introduced to Charlton M. Lewis. Strange how your memory is, that I remember that name. But he sat me down, and I explained that I knew a little drafting. He replied, ďWell, we might be able to use you here. It will involve a little janitorial work, too.Ē ďThatís fine.Ē No problem there.
This was a wartime project involving Mt Wilson astronomers.
Leslie:So this was actually during the war?
Livingston: Well, the war was more or less over. It was June 1945. But I got the job. The project had to do with the photometry of an array of model B29 bombers. Each had tiny lights where the guns were. These models were installed in the gymnasium of the then closed Pasadena Community College. The idea was to evaluate the defensive strengths and weaknesses of particular formations. The same task would now be done by computer modeling. Instead the astronomers employed stellar photometry, that being something they were familiar with. One of my bosses was Alfred Joy. Again I got some more lathe working experience. After about four months the project ended and I was drafted into the army. Incredible as it sounds, I was posted at Eglin Field in Florida to continue my ďbomber studies.Ē
Following my military career, I found eventually found astronomy employment on Mt Wilson as an assistant at the Snow Telescope working for the University of Michigan. It was there I met Keith Pierce.
Leslie:And Keith Pierce was running this?
Livingston: Keith Pierce was one of the visiting astronomers. The project was associated with the McMath-Hulbert Observatory.
Leslie:Which was at Michigan or nearby?
Livingston: Yes. In the course of that, Keith Pierce came out to do an experiment on the Snow Telescope. The Snow Telescope was somewhat unique in that it was all-reflective and therefore it would be used in the infrared. A lot of telescopes have lenses or windows in them and theyíre not useful there. He came out to do this project on the Snow Telescope.
Leslie:What were your early impressions of Dr. Pierce?
Livingston: As he entered the Snow I was prepared to say, ďDr. Pierce.Ē But the first thing I found myself saying was ďKeith,Ē just like that.
Leslie:That must say something about the kind of personality, his openness or his informality?
Livingston: I think so, yes.
Leslie:Now, he was a Berkeley grad at some point?
Livingston: Yes. He had a firm physics background. He had worked at the Radiation Lab in Berkeley for E. O. Lawrence. In fact, he had a little anecdote about it. He said at one time, he brought down the big accelerator by making a mistake on a vacuum valve.
Leslie:My sense of Lawrence, which is all secondhand, is that he would have been very displeased. He was a pretty hard-driving fellow. So you got to work with Pierce at the Snow?
I worked with Keith maybe for a month or more. Keith was doing, I consider when I look back on it very good physics work. We had infrared detectors. To cool detectors, today, we use liquid nitrogen or helium. But this particular detector was PbS and required liquid oxygen, which is a little warmer than the helium. We had to go down to Caltech and get bottles of liquid oxygen for this purpose.
Leslie:In those days were you doing most of the actual instrumentation building yourself?
Livingston: No. I was an observer only. I didnít build anything.
Leslie:And Pierceís background was more astronomy, or did he have also electronics?
Livingston: He didnít know electronics, but he was mechanically inclined. He could run lathes. The one thing I did get out of this earlier job just out of high school was to learn to run a lathe.
Leslie:It does seem to me that physicists and astronomers of your generation had a lot of electromechanical skills. The grad students now are very good with computers, butÖ
Livingston: Well, we didnít have computers at all. Another thing we learned was glass blowing, because frequently our apparatus or detectors had to be in a vacuum, and this involved glass.
Leslie:So you were up at Mount Wilson for someÖ?
Livingston: Two years.
Leslie:Okay. And during that time you were also going to school at UCLA?
Livingston: Yes, part time.
Oh, part-time. But you did finish your degree there at some point?
Leslie:Any other astronomers you remember from the Mount Wilson days that influenced your thinking?
Livingston: Well, the reason I went to Berkeley was I met this astronomer, Otto Struve. He was a famous astronomer and was head of the department at Berkeley. I guess it was because of him that I decided to — He asked me, ďWhy donít you come to Berkeley?Ē That was good.
Leslie:You must have impressed him.
Livingston: I donít know if I impressed him, but he turned out to be very important in my life.
Leslie:Did you share scientific interests? Any particular part of astronomy that you and Struve shared an interest in?
Livingston: No, he was a classical stellar astronomer. Born in Russia, he spoke all the languages, of course, including French and German. He had originally been the Yerkes Observatory Director.
Leslie:I grew up across the lake, Lake Geneva, and we could see dollar movies at Williams Bay, so we know Yerkes very well. As an aside, Chicago sold it off a few years back, but they preserved the observatory building itself. Last I heard they didnít know what to do with it. I donít know whatís going to happen with the telescope. Itís a magnificent facility. It would be a shame to see it just torn down. Berkeley would have been in the top few astronomy departments in the country at that time, I would guess.
Livingston: Yes, I think so.
Leslie:So tell me about your early experiences as a grad student, your adviser, and some of the projects you were working on at Berkeley.
Naturally I had to take all these courses physics and math courses. Just barely got through those. I never had a very good scholastic record. Then I started working with a guy named Gerald Kron at Lick Observatory. I spent one summer at Lick observing with the 36-inch telescope doing stellar photometry. Individual stars one at a time. Thatís the way it was done in those days. Then I got an offer to go back to Mount Wilson while I was still a grad student and work for Horace Babcock there in the solar department. Horace had built this magnetograph and installed it on Mount Wilson. He had two installations: One was in Pasadena at the old ďHale Lab,Ē and he worked with his father there, Harold Babcock. They were making magnetograms of the Sun. Horace was a very clever engineer and an astronomer.
Could you explain the magnetographs for me?
Livingston: The Babcock-type magnetograph employs the Zeeman Effect with a circular polarizer to modulate the light. If a spectrum line is formed in a magnetic field, say in the solar atmosphere, the line splits, or separates into two parts with opposite circular polarization. The amount of splitting is proportionate to the field strength. The problem is that the fields on the Sun are not very strong, so the splitting is not complete but just partial. By having an appropriate polarizer thatí s modulated, the line shifts slightly back and forth, and that causes the signal, from a photo tube, proportional to field strength. Babcock installed this very successful instrument at the Hale Lab in Pasadena. Then he installed one at Mount Wilson in the 150-foot solar tower. The problem there, it turned out, was all these TV stations on Mount Wilson had so much radiating power, and the modulator, the electro-optic crystal, operated at 60 cycles which is exactly the modulation of the TV signal. This caused problems that, in fact, we never did completely solve. The radiation was so strong on the observatory that if you wanted to watch TV, you put your antenna in the basement. With hindsight we should simply have changed frequency, but no one thought of that.
Leslie:Presumably you could have solved the problem by moving the magnetograph to another observatory.
Livingston: Well, they had the one at the Hale Lab, but they wanted to make use of the 150-ft tower and its fine spectrograph. My problem, my job, was to somehow fix this. Well, I never exactly fixed it, but it was okay, I managed to get it going.
Leslie:Now, you hadnít yet picked a thesis topic?
Concerning the thesis, I somehow got the idea — this was an era of what we might call ďimage tubes.Ē It was realized that photographic emulsions were not very efficient. Photoelectric surfaces, photocathodes, were much more efficient. Somehow they had to make use of that to improve imaging in astronomy. I doní t know how I got started on this, but my particular idea was to take a television camera tube, an image orthicon as it was called in those days, and to some somehow use that as an imaging device. TV normally works at 30 frames per second, 60 interlaced per second, and we donít have enough light in astronomy for that. So my idea was to cool the tubes so its storage time would be longer. In fact that did work. I was able to cool it to dry ice temperatures and it could store, or build up an image, for many minutes.
Leslie:How did you actually record what was stored on it?
Livingston: On a CRT screen. So it was a custom TV system.
Leslie:Yes. I guess it fell between the photo emulsion and the charged couple device of later eras.
Livingston: Yes, right. To jump ahead a little bit, when I first came here I worked on solar telescope design. But I was encouraged to continue my image orthicon project. Except now there was plenty of money! Mind you, when I was doing this same project at Berkeley, I didnít have any money. You can imagine that. Now I had money. So we bought the finest equipment and hired experienced people to design our TV system. Really, we had plenty of money; not like today! So we built this television system here in the Tucson Lab and brought it up here to the mountain to test it on the new 36-inch stellar telescope. Roger Lynds, who later was nominated to the U.S. National Academy of Science, joined the project. This was mainly stellar work.
Leslie:Now, you were hired. I think you mentioned that Keith Pierce was the person who got you out to Tucson and to Kitt Peak. Now where was he? In Michigan at that point?
Livingston: He was at Michigan. Then he became Associate Director of the solar group. There was also Aden Meinel who was stellar. Aden Meinel preceded Keith in the sense that he was part of the site selection group and chose Kitt Peak as an observatory site. Keith Pierce was McMathís representative, so to speak.
Leslie:Had you met McMath?
Livingston: I did meet McMath, but we didnít have any interaction to speak of. But yes, I knew him.
Leslie: Well, I guess you wouldnít have had that much time with him afterwards because he died just about the time —
Livingston: I had very little direct interaction with McMath. I didnít actually care for him too much because I didnít like his interaction with Keith Pierce. He was so domineering in that. But Keith had a lot of respect for McMath and they got along fine. McMath, of course, was very important to the observatory. Well, Iíve got a little story on that.
So McMath got this idea of building a big solar telescope in the Western US because McMath-Hulbert in Michigan was not a good site. McMath had this concept of building a large solar telescope. He was politically wise and realized that he probably couldnít just have his own solar telescope. So he expanded the concept to include stellar. He didnít give a hoot about stellar, but he wanted his solar. Anyway, the history of that is a complicated. An interesting item is that at some point McMath went to the office of the new Director of the National Science Foundation, Alan Waterman. Picture this. He goes into the NSF Washington office and says: ďAlan, I would like to tell you something. I just had your budget doubled because my friend so-and-so is head of the Bureau of the Budget. Now I would like to build a telescope, through your agency, in Arizona, and Iíve arranged for the money.Ē
Leslie:Wow. So McMath had a lot of political clout.
Leslie:Well, he was a very successful businessman and an amateur astronomer.
Livingston: Yes, exactly.
Leslie:But without his support, I suppose we wouldnít have had any Kitt Peak. We certainly wouldnít have had the solar telescope.
Livingston: Right. The original ideas that the astronomers had were not very ambitious. They wanted to build a small stellar photometry site out somewhere near Yuma. That was what they had in mind, and not this whole complex that you see here today on Kitt Peak.
Leslie:So I guess McMath gets some credit for that, certainly.
Livingston: Yes. Again, he wasnít interested in all these stellar telescopes, but he did realize politically that that was the way to go.
Leslie:Where were the main solar telescopes of that era?
Livingston: Mount Wilson in California and McMath-Hulbert in Michigan.
Leslie:So two. Were there also ones abroad? France had —
Livingston: Oh, yes. Pic du Midi for example, and other places.
Leslie:I just think of Walt Robertsí early career when he was at Climax.
Livingston: Yes, of course, Climax, indeed. Walt Roberts was the pioneer of that site. And that was a Harvard facility. He was working for Harvard.
Leslie:So it was a fairly small community of solar astronomers?
Leslie:Did you ever imagine yourself in grad school as ďIím going to be a solar astronomerĒ?
Livingston: No, I didnít.
Leslie:I just wondered whether an astronomerís career sort of follows —
Livingston: I would say that my career could have gone in any direction. I didnít have a preconceived notion as a youth that I wanted to be an astronomer. I could have done all kinds of things. In those days, there were a lot of job opportunities. Itís not like today. So if this hadnít worked out for me here at Kitt Peak I could have gone somewhere else.
Leslie:Well, I think you made the right choice for sure. When did you actually arrive in Tucson in person?
Livingston: I sent my wife Dorothy ahead to find a house. I said I wanted a house with a fireplace and a basement.
Leslie:All the things they donít have.
Livingston: She found one just six blocks north of the University of Arizona.
Leslie:With a basement?
Livingston: Yes. I was surprised. Yes.
Leslie:So you moved out here.
Livingston: I was still finishing up at Berkeley. She came out in January of Ď59 and I joined her here at March.
Okay. So construction had not yet begun —
No construction yet. There was nothing on Kitt Peak. They didnít even know where theyíd put McMath at that time.
Leslie:Okay. Did you get to see some of the early structural drawings and the different plans for what the telescope was going to actually look like?
Livingston: I did, but I didnít play any role in that actually. That was Keith Pierce and John Dunlop.
Leslie:Dunlop. Yes, yes, yes, thatís the Skidmore, Owings & Merrill architect.
Livingston: Yes. I didnít play any vital role in telescope design. My job ostensibly was the control system of the telescope. Keith thought I was an electronic guy. He saw me as that, so my job was to do the control system.
Leslie:Now, when you say the control system, you mean the heliostat?
Livingston: Yes, just the heliostat.
Leslie:Well, tell me some of the challenges of that and what you were doing.
Livingston: In fact my first job here at the observatory was to select the paint for the telescope. This was a rather crucial thing. I was told ďBill, find a paint thatís appropriate for a solar telescope.Ē I made tests with different paints. We had panels made and we put thermocouples on them and measured temperature rises.
Leslie:These were copper panels?
Livingston: Well, they were just small aluminum disks about a foot in diameter. There was a hole into which one could insert a thermometer. We tested many paints. We did find one interesting thing: ďappliance whiteĒ is not good. The very whitest paint is poor because is it canít radiate well what little is does absorb and gets relatively warm. I found titanium dioxide paint was best. This was my one contribution you might say.
Leslie:Well, I also heard that you had something to do with the determination of how the temperature varied as you moved up above the mountain toward the top of the heliostat.
Livingston: Well, I did experiments along those lines. We had short time constant thermocouples made up that responded in a tenth of a second time. We had a tower out here about a hundred feet tall, and as we raised and lowered these couples we saw how the micro thermals of the air behaved.
Leslie:Did you already know how high that you were going to —
Livingston: Ií m not sure that what we did there amounted to anything. I think that it was common sense that you wanted to get above the ground level which was heated by the Sun, maybe a hundred feet, or as high as you could afford. It wasnít based directly on these experiments, butÖ
Leslie:I see. But you must have known — clearly, even at that point you knew the basic configuration, at least that it was going to have these kinds of panels on the outside.
Livingston: I didnít know that, really. I never played any part in that. Certainly that was an important aspect of the system, but no. All I had anything to do with is the selection of paint and the electronic control system.
Leslie:Well, I want to talk a little bit more about the electronic control, because I guess it must be fairly tricky to get something — Youíve got to track the sun and you didnít have a computer control, I assume, in 1959. It was all electromechanical?
It was what we call ďopen loop.Ē There was no guider. We knew how fast the sun moves through the sky. The engineers just selected the drive to accommodate that.
Although, itís a pretty heavy thing that youíre —
Livingston: Well, yes, but that wasnít the problem. The problem had to do with moving the image around if you wanted to scan the image. But those were problems that the engineers undertook and solved. I didnít actually do much.
Leslie:I did want to ask whether Keith Pierce had talked about, in your conversations, about the design, because itís one of those things that where Dunlop and Myron Goldsmith, who were the architects — You know, I look at the original designs that were done by Zabrinksy, the engineer, and theyíre kind of awkward looking, and it supports the triangle, but itís not very elegant. I just wondered when you saw some of those designs whether you were as struck by their elegance as a lot of later architects and people would be?
Livingston: Well, one question you might ask is why the telescope is so big? Well, first of all, you need aperture to obtain image resolution on the Sun. So the old telescopes that were 10 inches in diameter havenít got it, particularly as you go into the infrared. So you need aperture. And you need photons. You might think that the sun is very bright and it is, but once you put the light through a spectrograph, and you go down to a fraction of an angstrom of the spectrum, and you begin to want to observe things quickly because seeing is moving this image around, youí re photon limited, even with the Sun. So that leads you to a large aperture. But a problem with large aperture is heat. One way you get around heat is to make the focal length long so itís not like a stellar telescope, which is maybe f/3. The f-ratio of the McMath-Pierce is f/60, and the intensity in the image is really only about four times that outside in the free air. So itís not a problem. You donít break filters you put in the beam. You donít hurt yourself by burning yourself. Things like that. So you want the aperture for the resolution, and you have to have a long focal lengthy so you donít get into a heat problem. You end up with what we have here, a big, long telescope.
Leslie:As far as Ií m aware, nobody else was thinking on that kind of scale at that time.
Livingston: Well, thatís Keith Pierce. Heís the origin of these ideas, and I certainly have to hand it to him on that. His other important idea: all reflective. As soon as you put in windows or lenses, youíve got limited bandwidth. And this telescope goes back to the fact that Keith had this basic physics background from Berkeley and he knew his photometry and he knew his detectors, and he thought we should have a telescope which was capable from observing from the ozone cutoff at 3,000 angstroms in the UV to 20 microns in the IR where the atmosphere gets opaque again.
Leslie:And to have that kind of spectral range required that you have something of a — what is the total size of that mirror?
Livingston: Well, itís 2 meters at the top in the heliostat and 1.6 meters at the imaging mirror in the tunnel.
Leslie:Thatís great. I think one of the architects compared the telescope to a 300-foot focal length camera. I donít know if thatís —
Livingston: No, that okay. It has a 300-foot focal length.
Leslie:Because of the way that it bounces.
Livingston: Yes. It has some disadvantages, the long focal length. Itís more susceptible to atmospheric conditions inside the telescope. But I think that how it developed into the particular configuration that you see is because of Skidmore, Owings & Merrill forward thinking. I just saw it materialize before my eyes, so to speak.
Leslie:Well, I will ask you later about your impressions, because I think to anyone seeing it in a photograph and then seeing it as I have today for the first time it is really quite an impressive structure. Itís got a certain austerity to it. Itís quite remarkable. Iíve never seen anything else like it. So the to get around the disadvantages of its scale, they need to inhibit internal air turbulence?
Livingston: Right. They did as much as they could in a straightforward way to ameliorate air temperature variations. They found this tube and strip material made of copper with the expanded tubes through which a coolant, or heat liquid could circulate, whichever you need to realize isothermal conditions. This is done in the outer skin of the telescope and in the lining for the tunnel.
Leslie:I guess we should start with the simple part, which is, is one of the reasons to drive much of the telescope into the mountain for thermal control, or why not just set it up on top of the mountain?
Livingston: Well, we wanted to get above the disturbance of the ground, so maybe youíd just say we wanted the tracking optic to be 100 feet high off the ground. Then you have to feed something. Well, the traditional way of doing that would be to use a coelostat and bring the beam straight down, but that was awkward because of the long focal length needed.
Leslie:You would have had to go too far underground.
Livingston: Yes, it required going a long ways straight down. Another aspect of the design is the choice of the heliostat and not a coelostat. A coelostat was the sort of standard way to build a solar telescope. Instead a heliostat was selected. It has the advantage that it will track an object across the sky, either the Sun or a star. It has the disadvantage in that the image rotates. For lots of purposes, the rotating image is not a problem, but for a big spectrograph, this could be a problem. This led Keith Pierce to the design of a vertical spectrograph which rotates.
Leslie:Okay. So once you decided on the heliostat, and you want to be a hundred above the surface; presumably cost enters into this at some point. You donít want to build a 500-foot tower or something. So you bring the beam along the heliostat axis, after it hits the first mirror, it goes all the way down the imaging mirror. How long is the distance?
Livingston: About 500 feet.
Leslie:500 feet, all the way down to the end of that tunnel and then there must be another mirror there that sends the light into the observing room and the spectrograph.
Livingston: Yes, the number 3 mirror.
Leslie:The number 3 mirror. But, there were at least two other heliostats as part of this, if I remember?
Well, I would say they are an ďadd on,Ē really.
Oh, that was later.
Livingston: But you mentioned expense. Now, let me comment on that. Skidmore, Owings & Merrill had some ideas on that one. They suggested we put the telescope on top of Kitt Peak itself, the high point out here at the north side of the mountain, and cantilever it out over the valley, so the actual distance to the ground would maybe be 1000 feet.
Leslie:Which would have looked spectacular, I guess.
Livingston: But that would have cost a lot of money. Another guy, named Bowen who was from Mount Wilson and they were poor as church mice, but he got into the spirit of things here and he said, ďYou should really put it is on the top Baboquivari Peak, 12 miles to the south of here.Ē This is a volcanic plug that comes up. Itís about 7500 feet high. All they have to do is drill down through that mountain. Of course, these days, even to think of that would be against the protocol of the Indian sacred mountain.
Leslie:Thatís true. Ií m sure it wouldnít have been too cheap, either.
Livingston: It wouldnít have been cheap.
Leslie:A little Project Mole Hole or something like that.
Livingston: Yes, right.
Leslie:But it wouldnít have improved the performance to have done either of those two options?
Livingston: Well, we can only kind of guess about the Baboquivari Peak business. It was an isolated peak, which would be a favorable situation. We wouldnít be affected much by ground disturbances.
Leslie:So when I look up at that telescope and I see the structure before it disappears into the ground, what Ií m really looking at is thermal and wind shielding?
Leslie:Thatís only there really to make sure that beam is undisturbed on its way down.
Livingston: Yes, which is a problem. It isnít a dominant problem, I wouldnít say. Telescope seeing is not bad here, but it has to be —
Leslie:Maybe for the tape, ďtelescope seeingĒ is what happens from thermal disturbances in the air as the light passes through.
Livingston: Right. We have a different philosophy at the Dunn Telescope at Sac Peak. Itís a tower telescope. It has a window at the top, a quartz window, and inside is a vacuum, so that takes care of the long throw and a folded beam. To take care of that situation. But that arrangement would go against Keithís view that you shouldnít have any window.
Leslie:Oh, because of the spectral range.
Livingston: Spectral range. Right.
Leslie:Iíve forgotten when the Sacramento Peak telescope was done. Maybe 1969, or something like that.
Leslie:But it wasnít that you couldnít have built a vacuum telescope here. Itís that Pierce didnít want to build one.
Livingston: Let me comment that the Russians did build a telescope almost exactly a duplicate of the McMath, but they put a window on it and had it in vacuum. This is at Lake Baikal, and if you looked at the telescope, youíd say, ďHey, thatís a McMath.Ē
Leslie:Was that built long after?
Livingston: It was built sometime after, and it has never performed too well.
Leslie:Because of that spectral range issue?
Livingston: No, I doubt that. I mean what about the Russian 6-meter telescope? How is it — I donít know what the answer is.
Leslie:Just the engineering of the area.
Livingston: Yes. Thatís outside our discussion.
Leslie:Yes. Okay. What Ií m trying to get at, and you would know at least from having talked to Pierce and other people, is how much input the scientific staff for the telescope had in what it actually ended up looking like?
Livingston: I donít think we had too much input actually. I think it was Keith Pierce and the guys at SOM who had some ideas about things, very original ideas actually, and between them they came up with what we have. My personal input was almost nothing. I donít know about other people. Iím not aware of anyone who had much input.
Leslie:I wasnít very much concerned about whether you felt personally you had much impact over it, but whether you think of it, well, you just build scientific instruments because it will work the best that you can make it work and you doní t worry much about what it looks like aesthetically, etc.
Livingston: Thereís that and thereís another interesting thing about the era in which the telescope was conceived and built: It was not subject to peer review. McMath simply pushed it through.
Leslie:Interesting point. Well, elaborate a bit on that. Thatís really interesting.
Livingston: Well, nowadays, you get an idea and you submit a proposal. Then itís batted around. Years can go by before it materializes. By the time it comes about, it may be obsolete. I see this happening all the time. One thing good — well, for good or for bad, Iím not sure. This McMath telescope was not peer reviewed.
Leslie:It also doesnít sound like you had any budget worries either, that you had a fairly significant budget from the beginning and didnít have to worry about that so much.
Livingston: Well, I think there was concern about the budget, but obviously it wasnít an extreme problem.
Leslie:But you had, I donít remember what the total cost of it was.
Livingston: About $7 million.
Leslie:$7 million. Okay. When the construction began in 1959, 1960, you knew you had sufficient funds to complete as designed and such.
Livingston: I believe so. One thing that did cut into the telescope in one way or another was the cost of the highway up here. Part of the cost of that road came out of the telescope budget. I think that that had an impact of some sort.
Leslie:You know that as we drove up today, we thought exactly that. I thought, I wonder how much it cost to build this road versus the telescope.
Livingston: It cost a couple million dollars to build that road.
Leslie:Iím not surprised.
Livingston: An interesting thing is that the very first road up Kitt Peak, the old road that you can see as you drive up, only cost $50,000. Now this was just a contractor who had a tractor and he made that road. It was improved over the years by continually grading and doing different things. But the basic road came in at about $50,000 which is not very much for five miles.
Leslie:No. No, itís not. Not at all. We were talking about the Sacramento Peak telescope. At some point, you were working with vacuum solar telescopes?
Livingston: We built one here.
Leslie:Yes. Could you say a little bit about that, and why you needed that in addition to — Was that for a different purpose than the larger?
Livingston: It was for a different purpose. This was the era of Skylab, and they needed synoptic coverage, daily observations of the Sun, to support Skylab. Our director at that time was Leo Goldberg.
Leslie:Oh, he hadnít come up before.
Livingston: He had something to do with the founding of AURA in the 1950s. He became overall Kitt Peak Director, I forget the date.
Leslie:But heíd been with Pierce at Michigan, if I remember correctly.
Livingston: Yes, he had. He had been with Keith. He asked the staff to make proposals for what we should do for Skylab because Leo was very interested in space technology, and how it might apply to solar. Jack Harvey came up with the idea of a low scattered light telescope, and I came up with the idea with what we have here, the ďvacuum telescopeĒ with its magnetograph. Leo went for the vacuum telescope.
Leslie:What is the scale of that? Itís usually called a 60-centimeter.
Livingston: Its aperture is about 60 centimeters.
Leslie:Is it somehow connected to the rest of this telescope?
Livingston: Physically itís built onto the east side of the McMath. We can take a look at it later. However itís completely independent. The idea was that the McMath-Pierce, or the McMath Telescope as weí re referring to it now, was a research instrument that would be passed from scientist to scientist to do whatever they thought best. This new the vacuum telescope was dedicated to daily observations at first to support Skylab.
Leslie:Well, one thing, when you look at it — as you pointed at that the Russians built a kind of copy, but with a vacuum — it doesnít seem like anyone else wanted to build one like it. I wonder why that is. Usually when you build an accelerator, someone wants to build an accelerator thatís like it or bigger. Fermilab builds something; Brookhaven will build something like that. But in this case, it seems to be almost a unique instrument.
I think the trend in solar telescopes was toward high resolution, and our two meter aperture, the atmosphere is very seldom able to take full advantage of that except in the infrared as it turns out, which in fact proved to be important. But the trend in solar telescopes has been to go smaller. Part of this is cost. Also there has been a trend to concentrate on high image resolution. This was mainly imaging, not so much spectroscopic. Recall the reason we needed this big aperture was to put the photons through the spectrograph. Recent workers have stressed imaging with narrowband filters. Another factor was ďadaptive optics.Ē Combined with fast computers one is able to correct for atmospheric seeing in real time.
Since you brought up the infrared, it might be a good time to talk about that, because in reading Karl Hufbauerís history of solar astronomy as a kind of standard history from back in 1991, it doesnít say much about the McMath Telescope. It still has a few pages, but you get the sense that this was on a large scale and it was a unique achievement, but everything was going the other way. It was sort of increasingly —
Livingston: I think that was because of the push to high resolution imaging as opposed to a spectrographic work.
Leslie:But it would be fair to say that it really wasnít just serendipity that made this very good for infrared, that Pierce was thinking of this whole spectrum, this larger part of the spectrum.
Livingston: Keith certainly had in mind the infrared. We mentioned the spectrograph here. Another instrument —
Leslie:That would have been the main source, at least in the beginning.
That was the main source of everything. But we had another staff member join us, Jim Brault, and he was a very clever physicist. He found the spectrograph unsatisfactory for various reasons. He thought we should have a ďFourier transform spectrometer,Ē or FTS.
Youíll have to explain a little bit about that.
Livingston: Yes. Well, I canít explain it because I donít understand it. But itís basically an interferometer. It has two moving mirrors in it, and you get interference between them and this interference is recorded, and compared to a stable laser. This signal is later transformed into a spectrum. Jim had ideas for a new and unique FTS. It is capable of performance throughout the solar spectrum, out to 20 microns and down to ultraviolet. It can be used with laboratory light sources to measure previously unknown materials, molecular mostly.
Leslie:And that would have been impossible at any other solar observatory?
Livingston: Right, because they didnít have the optical transmission.
Leslie:Yes. Even though I suppose at the beginning it was anticipating that the main use now would be for the infrared, at least somebody was giving some thought to the importance of a full spectrum.
Livingston: Right. And neither our spectrum here or at FTS are primarily oriented at high-resolution spectrum images. Of significance is the wavelength span. One thing about the FTS that Iíll just mention is that in principle, anyway, you can have a very wide bandwidth. You can observe from 3000 angstroms to 6000 angstroms in one observation.
Leslie:And this is about the only place that that could be done?
Livingston: It was done earlier in France by Pierre Connes. Braultís important contribution was continuous scanning as opposed to slow step-wise scans of Connes.
Leslie:Before we get off instrumentation, we should talk about your own, the integrated light feed system. Any background about that? Was that just an interest of yours?
Livingston: At some point around 1974, I began to collaborate with Dick White at the High Altitude Observatory in Colorado. He was very interested in Ca K and thought it would be very good to make synoptic type observations of the Sun in the Ca K line. Severny in the Crimea, Russia, had begun making observations of the Sun-as-a-star. Looking at the entire solar disk, instead of just a single place. I guess it occurred to me, well, why donít we also take spectra of the whole Sun. And so we started. The way that you do that is that instead of having an image of the Sun, you just have flat mirrors to produce plain sunlight. So we arranged to install flat mirrors in the heliostat beam. Eventually, we had a flat mirror as an option to the 1.7 m concave. It is lowered from the ceiling, a large mirror. So we can observe the Sun as a star in this case.
Leslie:And that was really the first time that that was being done?
Livingston: Except for Severny in Russia.
Leslie:One of the things that most intrigued me about Claude Plymateís history was he said that ďMany think of this telescope more like an optical lab that has a special feature: the ability to deliver a telescopic image. In a conventional telescope all instrumentation must be designed and ready to mate to a special instrument port.Ē I was intrigued by his notion that this was more like an optical lab.
Livingston: Thatís true. Because these mirrors, we can deliver the image to any number of places. This number 3 mirror. Remember the heliostat, down to the image forming number 2, and then back to what we called the number 3 mirror. That number 3 mirror can be moved up and down this track. Weíre talking a hundred feet or more. That gives you the flexibility then of picking off the beam and sending it to a lab upstairs, or a lab in here, or to another observing position. At these other observing positions, you can build or bring in apparatus, maybe bulky apparatus. Itís not like trying to hang something on a telescope thatís moving. So thatís an advantage to this system.
Leslie:Can you give me some examples of equipment that were brought in?
Livingston: Look out in the hall here and youíll see a bunch of shipping cases. These contain a 12-micron infrared cryostat from NASA at Goddard Space Center. Itís quite a big deal, actually. The whole spectrograph is at liquid helium temperature.
Are all the instruments brought here — how am I going to say this properly? Are there people who do spectroscopic work who arenít particularly interested in solar astronomy?
Livingston: Well, yes. There are planetary, stellar, lunar, and for the FTS people they even bring their own light sources. They come from all over the world, particularly from Germany and France. A current experiment involves heterodyning techniques.
Leslie:So itís a laboratory beyond being just a solar observatory. It really is a laboratory. Iím not sure I know the difference between a laboratory and an observatory, I mean in the sense that Iíll talk to astronomer friends and theyíll say, ďWell, everything was really an observatory until the mid-nineteenth century. Laboratories were just a special kind of observatory.Ē
Livingston: To use stellar instruments, the telescope itself moves and your equipment mustnít be too big. It has to fit on the telescope. The exception would be the so-called coudť arrangement, which is more like what we have here.
Leslie:So that is a kind of unanticipated advantage of the scale of this place.
Livingston: I think so, yes.
Leslie:So you can bring in all kinds of equipment that would be too large for other —
Livingston: Yes. Right.
Leslie:Thatís quite interesting.
Now I wanted to ask. Itís related to what we were just talking about. Itís the flexibility of the instrument over time. One characteristic of a well-designed laboratory, like Bell Labsí original Murray Hill lab, is that it adapts over a long period of time; you can do different kinds of work in it. Itís very flexible. I would guess that observatories arenít, for the most part, so flexible.
Livingston: I would say there are two sides to this story. The flexibility that youíre talking about is certainly one. Visitors come here and they look at what we have and they say, ďGee, this all looks pretty old here.Ē Yes, but I remark itís paid for. In addition, by not changing things, we have continuity in our observations, particularly the spectrograph. You have proposals to do experiments. They typically do experiments in space, for example. They last about two or three years. Then thatís interrupted by something. Here, weíve been doing the same thing since the 1970s. The result is continuity. Iíve been impressed, for one thing, by the lifetime of photomultipliers. The photomultiplier Iím using in the other room there was purchased here in 1965. Another advantage over space experiments is that if you devise a new gadget you can test it next month — if not sooner.
Leslie:Those photomultipliers are older than probably many of the astronomers here. [Laughs]
Livingston: Oh, absolutely, yes. And itís really amazing that these photomultipliers, typically made by English Electric in Great Britain, are so durable. But I think in part, using them keeps them alive. They have inside something called a ďgetterĒ action. Itís like an airplane — a working airplane is a healthy airplane.
Leslie:Do you still attract ambitious young astronomers who want to move into solar?
Livingston: Well, now youíre getting into a touchy area, because I think young people think you should be able to sit at a computer and do everything. They expect to have the data delivered to them. They donít know (Ií m prejudiced here, obviously), they donít know what is behind the hardware. They donít have any touch with that. Theyíre certainly very good at getting the most out of the data that comes and theyíre very skilled at it, but from my old-fashioned viewpoint, theyíve lost touch with the laboratory environment.
Leslie:Thatís a very intriguing observation. You and Keith Pierce and the other astronomers here, youíve lived with this thing for your entire career, virtually. I assume that Keith Pierce was on the mountain pretty often.
Livingston: Well, yes.
Leslie:And youíve been here for 50 years.
Livingston: Well, when I make these derogatory sounding comments about young people, I think ití s true that they expect that you can sit down at a computer and get anything, but of course, you caní t. Itís well known, particularly in physics laboratories, you have to build your apparatus to really know understand it. For example —
Leslie:Hadron Collider at CERN.
Livingston: I mean that isnít working yet, and theyíve really tried hard.
Leslie:Did you ever have any start up issues with the McMath Telescope, or did it work pretty much as expected from day one?
Livingston: Originally, the spectrograph was designed to be a vacuum spectrograph.
Leslie:Oh, you didnít say that.
Livingston: Right. It was never operated as such. There is an optical advantage to a vertical spectrograph in terms of stability That is to say, if there are any air currents in it, they tend to be up and down along the beam, as opposed to a horizontal spectrograph in which air currents cross the beam. So I think that our vertical mounting here was good enough that we didnít need the vacuum. And vacuum involves a window, obviously, at some point. You could have different windows for different wavelengths, but thatís a complication. It never was done.
Leslie:So in the end, you just used the more conventional spectrograph, and you brought the beam in from the number 3 mirror vertically and didnít have another mirror.
Livingston: Right. There is another spectrograph in the hallway, which was built for early infrared work.
Leslie:When you say early infrared, how early did you start doing infrared on this telescope?
Livingston: A graduate student named Don Hall was the prime mover of a program to map the Sun in the infrared. He used this horizontal spectrograph. The grating in the vertical spectrograph was not appropriate for infrared. The rulings were too fine. In 1992, a second grating was installed for infrared work, which is, by the way, the largest grating in the world; about two feet across.
Leslie:Wow. Ií m used to that. You know, Henry Rowland was a Hopkins guy, so we know about diffraction gratings, but not at that scale.
Livingston: Right. This was actually — Well anyway, the history of gratings is a whole different subject. I forget the source of this IR grating. It might have been someone at Johns Hopkins.
Leslie:We still have the ruling engine that they used back in 1900. Nobody uses it today.
Livingston: Well, anyway, we got this grating and work was done by Don Hall in producing the first solar atlas in the infrared.
Leslie:I was going to ask you at some point about what you think that the key contributions of the telescope have been over the last 50 years.
Livingston: I hate that question.
Leslie:You donít have to put them in order.
Livingston: Actually, there has been a list of contributions and it is on the Net (www.nsokp.edu/node/u1). Perhaps most useful is a series of solar spectrum atlases prepared by Lloyd Wallace. These are based on FTS data and include the quiet photosphere, sunspot umbrae, and the Sun-as-a-star. They are referenced daily by astronomers the world over.
Leslie:It may not be your list, though.
Livingston: It isnít my list, but itís a good list. I donít have any objection to it. Itís quite a lengthy list. But weíd really have to refer to it to find all the things. My tiny discovery was water on the Sun. It was not known before.
Leslie:That doesnít sound like such a tiny discovery to me.
Livingston: Well, it had its day; about a month or so. Water on the Sun is found only in sunspots. You canít observe it on the quiet disk of Sun. Itís too hot. Water will dissociate. But in the cooler parts of big spots, you can measure the equivalent of about two centimeters of precipitable water.
Leslie:I would have never guessed. When was theÖ?
Livingston: I donít know, 20 years ago.
Leslie:Iíll go look at that list on the web, but conventional wisdom would say what? I imagine that infrared mapping must be pretty high on that list.
Livingston: Magnetic fields I think were another strong point here because they were all flux-sensitive experiments. In other words, you need a good signal-to-noise ratio to detect weak fields, and we found weak fields on the sun, much weaker than thought. What else? I donít know. Weíd have to consult that list.
Leslie:Okay. Iíll dig into that. A couple more kinds of questions. What is the lifespan of this instrument? Or what happens as the 4 meter Advanced Technology Solar Telescope (ATST) comes online as scheduled, etc.? What that means for this facility and the extent to which that new facility owes a debt for its design, etc., to this one. How does the McMath contribute to its successor?
Livingston: That is a complicated issue. The present plan is that the McMath and the Dunn at Sac Peak will remain open until the ATST is proven operational. The National Science Foundation feels that when you get a new facility an old one should close. But there are a lot of yet to be verified technology in the ATST.
Another potential problem is with our landlords, the Tohono Oíodhams Indian Nation. I believe the original contract was to the effect that if we leave, we had to restore the mountain it to its original condition. Well, that would cost an unbelievable amount of money and not likely to happen. So I donít think that theyíre going to tear down the McMath Telescope. What may happen as the modern equipment shifts to Hawaii and ATST, some university or local organization will probably move in here and continue programs as appropriate.
Leslie:Now, are there ways in which this can be updated? I know that Ií m not an expert on adaptive optics and so forth, but are there ways in which the performance of this instrument can be improved?
Livingston: Oh, absolutely. There is an adaptive optics system installed right now. It is a very simple one. It is not a high order system like they have Sacramento Peak on the Dunn, for example, or that is planned for the ATST, but it does work under certain conditions and does a very good job. One problem with adaptive optics is that you have to have a source, that is to say you have to have a reference point, like stellar instruments have a sodium guide star at night to look at if they want to sample and correct an image field. Or if youíre lucky, you have a normal star, but you canít always have a normal star bright enough. So what do you do about the sun? I donít know. The adaptive technology is not fully mature yet.
Leslie:Okay. The second half of that question was the extent to which this instrument made made ATST possible, whether in terms of training people or the kind of instrumentation or the kind of the research problems and trajectory that were pioneered here.
Livingston: I am unsure of the full answer to that question. Except Pierceís philosophy of broadband coverage, that we shouldnít have windows, carries over to the ATST. Our example is different than most solar telescopes in the world. Most aim at high resolution and restricted wavelength coverage. Of course, the ATST will aim at high resolution, but thereís also a proviso there in the sense that we need the wavelength coverage too. I donít know exactly how they will handle that.
Leslie:Thatís an important legacy, yes. Thatís very interesting. Where does ATST stand right now — have they actually started construction? It was supposed to start this year.
Livingston: No, it hasnít started yet (as of May 2012), but the design is well along. It has been funded to the total projected cost. Because of various delays the cost is going up. I would say the main input to ATST has come from Sacramento Peak and from Hawaii astronomers at the Institute for Astronomy. Not so much input from here at Kitt Peak.
Leslie:What is the staff size for the McMath-Pierce Telescope now?
Livingston: The staff of PhD astronomers is perhaps six. Technical staff depends on need and is shared with other mountain telescopes.
Leslie:Well, that is fairly small. Do you have also post-docs that are visiting?
Livingston: Yes, post-docs and foreign astronomers. We also have a summer program sponsored by the NSF that consists of undergraduates, Research Experience for Undergraduates (REUs) and also for teachers. So there are teachers that come here.
Leslie:I just wondered if you look at the website, itíll say — No, I guess ití s from Plymateís history where I remember this. It said, well, the McMath-Pierce would be a kind of test bed for Advanced Technology Solar Telescope.
Livingston: Actually, I played a role in the following sense. Pardon my mentioning this. I proposed about ten years ago that the McMath could be upgraded to 4 meters. Thereís enough room in the tunnel to easily accommodate a 4-meter mirror. All we have to do is change the heliostat to 6 meters. At that time, they supported me and they gave me engineering assistance, and we worked through a preliminary proposal. A proposal at that time was that it would cost about $20 million to build a 4-meter. And you know what the ATST costs: a quarter of a billion dollars. You could say, if you step back from that and the $20 million to make the McMath a 4-meter, which could have been a test bed for the ATST to try out the ideas. But of course, that wasnít what did it in. What did it in was the NSO Director had other ideas.
Leslie:Thatís got to be fairly standard.
Livingston: Yes. You canít buck the Director.
Leslie:I think itís tough. When the Superconducting Super Collider was still a viable option, Fermilab was going to be the test bed, and they were not very happy about that idea. When Livermore was building the National Ignition Facility for fusion, the Laboratory for Laser Energetics at Rochester was going to be the test bed, and they didnít like that much either. Nobody likes to be the test bed.
Livingston: But you know, it would have been almost in the petty cash category, in the long haul.
Leslie:Does AURA or somebody else have that proposal somewhere in the files?
Livingston: Yes, but it had its day. I could give you a copy of the proposal and you can read it with amusement.
Leslie:No, but I think itís an interesting endpoint. What do you do with —?
Livingston: I, myself, was not committed to it wholeheartedly. That is to say, I thought it was neat idea and they gave me support for it, but when it didnít go over, I just went on to something else.
Leslie:Yes. McMath Telescope is interesting because itís had several lives. It began as one kind of instrument, then it had all the infrared work took hold. There was also the vacuum telescope work done for NASA Skylab.
Livingston: I honestly do believe that we could have converted the McMath to a 4-meter aperture. One problem that we faced and ATST does face is heat. Youíve got 4 meters and you keep the focal length the same because you canít very well change that in the structure. And youíve got heat. Itís a big problem, and itís going to be a big problem in the ATST that I donít think theyíve necessarily solved it. They have to have heat-absorbing structures there at the focus and they have to be foolproof.
Leslie:Yes. And you avoided that problem with the design of this telescope?
Livingston: The long focal length.
Leslie:Yes, thatís very interesting. I have only one more question, which was mostly about aesthetics. I was prepared to be wowed when I came to see it because Iíve seen photos of it. I just pulled out a few. Since youíre somebody who does have an interest in aesthetics and photography and the color in light and nature work, you really do have an interest in that. I wondered the extent to which you look at that instrument and think about it as a piece of architecture, as something other than simply a utilitarian structure.
Livingston: No, I really did not concern myself with that.
What I have been doing this past year is watching sunsets on the west auxiliary, and that has proved interesting. What I have learned is that — and other people tell me this is already known, but the atmosphere can be very stable over a hundred miles, and you can have very good seeing, in fact, you typically do have good seeing at sunset. I have video recordings of these things and you can see it very clear. I think itís remarkable. Youíd think that when the Sun is setting the light is traversing perhaps 50 atmospheres and should be all scrambled up. That isnít what happens.
Leslie:I wanted to get a copy of your book, by the way, before I came out, but the only one I could at find — I couldnít get it at Hopkins and the only one was $128.
Livingston: Lynch and I are working on a self-publishing scheme. Cambridge has given us complete control. They said, ďWell, we already did a second edition.Ē They donít want to do another. Theyíve just given us the copyright to do what we want. We have now reprinted it ourselves.
Leslie:That is excellent news. I was just sorry I couldnít get a hold of it before I came out. But it was kind of interesting because it was a famous architectural critic named Reyner Banham who came out here in the Ď80s. He said this was the most marvelous and moving of all mankindís works in the desert.
Livingston: Did you see at the image of the McMath at Speedway underpass at I-10?
Leslie:I better look. I was in hurry to get out here. Iíll do that. Iíll have to say that Banhamís probably wrong. I would guess that the pyramids in Egypt would be the most interesting. [Laughter] But I will say this. I doní t know if youíll agree, disagree or have no opinion, but looking at the schematic for the Advanced Technology Solar Telescope and at this one, I doní t think that ATST will ever make any architecture books, nor is Sacramento Peak ever going to make any architecture books. This is truly a unique design in that it looks like pure structure, but it has a certain real minimalist aesthetic that is very appropriate to a student of Mies van der Rohe, Dunlop, and Myron Goldsmith. Itís a beautiful piece of engineering, and itís also a wonderful piece of science
Livingston: Well, I agree with you on that.
Leslie:I hope other solar astronomers do too. I looked at the Advanced Technology and thought, ďIím sure it would do the job.Ē But it wouldnít grab me as an architectural historian.
Livingston: Well, you can log onto your computer wherever you are and get a picture of the McMath observing room online. Right now.
Leslie:Of this telescope?
Leslie:Oh, I didnít know that. I will when I get back.
Livingston: Well, is there anything else for the record?
Leslie:No, I would say this has been a lot of fun for me. I hope I havenít given misinformation and stuff, but I donít think we covered anything sensitive like that.
Livingston: I donít think so. Well, thank you very much.