Chasing the Stars at Washburn Observatory

Norman Gilliland: Welcome to University Place Presents. I’m Norman Gilliland.

Perched atop a hill overlooking Lake Mendota in Madison is the Washburn Observatory. It has been observing movements in the sky by stars and planets and other entities since the 1880s. And along the way, it has transformed the way we think about the universe. We’re going to find out how from my guests. And they are Jim Lattis, the director of the UW-Madison Space Place, and Kelly Tyrrell, science writer. And they are co-authors of the book Chasing the Stars, published by the Wisconsin Historical Society Press in 2024. Welcome to University Place Presents.

Jim Lattis: Thank you, Norman.

Kelly Tyrrell: Yeah, thank you, Norman.

Norman Gilliland: Looking at the observatory itself is a fascinating thing because there it is, pretty much now in the middle of a campus, a university campus, although it is prominent as it overlooks the lake still. Why did it get chosen back in the 1870s?

Jim Lattis: Yeah, it was on the western edge of campus at that point. Part of the large expanse that stretched westward that used to be called the University Farm at times. And it was far enough away from the city. But although the city was small at that time, but far enough away from what modest lights there were, but also smoke, sources of smoke, and things like that which did eventually engulf the observatory anyway, but it was pretty much the western, the westernmost structure of the university at the time.

Norman Gilliland: And whose idea was it?

Jim Lattis: So it was Cadwallader Washburn, who was a former governor and a very successful businessman. And he was a political ally and associate of John Bascom, who was the president of the university. And they had it in mind to transform the university with a research institute there.

Norman Gilliland: John Bascom was the university’s sixth president, and he believed in coeducation and saw the university as a place where you could bring students together and really sort of stake a claim for the university as a research institution. And at the time, having an observatory was somewhat similar to having a Department of Computer Science today. It was a way to establish a university as a research entity. And he modeled it after places like Harvard and Michigan.

Jim Lattis: Wisconsin always had this thing about Harvard, didn’t they?

Norman Gilliland: Would be the Harvard of the Midwest.

Jim Lattis: That’s, something like that, yeah, yeah.

Norman Gilliland: What kind of telescope, though, if we’re talking 1880 or so?

Jim Lattis: Well, so telescopes of, research telescopes of that day were almost invariably what we call refracting telescopes. Instead of having a big mirror, the way modern research telescopes have, it would have a lens as big as you could afford, a lens up at the front of that telescope. And Washburn specified that he wanted a telescope that had a lens bigger, well, comparable to or larger than Harvard’s.

Norman Gilliland: There we go again.

Jim Lattis: Yeah, that’s right. And so Harvard’s telescope, the one that he was comparing to was a, is, they still have it, a 15-inch telescope. That means the lens, the diameter of the lens is 15 inches. That’s how astronomers talk about the size of the telescope. So we have one that’s 15.6. We often say 15 1/2 inches. And that pushed Harvard down one in the rankings. And so that telescope was the third largest in the United States when it was installed up there at Washburn Observatory.

Norman Gilliland: What were they looking for? What were they looking at?

Jim Lattis: Well, so astronomy of that era was very different than what we think of astronomers doing today. We often use the term astrophysics today, which helps distinguish between what astronomers do today. And astronomy at that time was carried out with a number of specialized techniques that amounted to measuring the positions of stars in the sky. That was not the only thing astronomers did, but it was the primary work of astronomers. Sometimes, they were measuring positions of the sky in the sense of measuring one with respect to another, so that you might, say, make up a star chart, a star atlas or something. But sometimes they were measuring one star with respect to another of stars that are in systems, gravitational systems of stars. And you measure the positions of one with respect to another, to observe their orbits and try to derive information about those star systems.

Norman Gilliland: You have a notion of how far they could actually see?

Jim Lattis: The ability to see into the universe does increase as your telescopes get bigger, but it’s just a question of how dim an object you can look at. You can see pretty distant things, even with your eye [chuckles] just with the unaided eye. So what, but what we usually think of is that these telescopes were not specially designed to detect, say, really dim galaxies. The kind of things that we do look for to tell us how the universe has evolved. And so that’s why they could get by with much smaller apertures, 15 1/2 inches compared to, say, you know, our large telescopes these days have mirrors measured in meters. [Norman chuckles] And so they have penetrating power into space vastly greater. That wasn’t the primary goal of these telescopes.

Kelly Tyrrell: One thing that I think surprises people that the instruments at a place like Washburn was doing too was actually measuring very accurate time. And so you could look at the transits of stars across an instrument like the meridian telescope that Washburn was equipped with, in addition to the refractor that we’ve discussed. And by getting very accurate celestial time, observatories could then sell that to industries like the railroad and watchmakers, who were very interested in establishing very, very specific and very accurate timing.

Norman Gilliland: I think, so what would that instrument have looked like?

Jim Lattis: That’s a meridian circle telescope there. And the second director of Washburn Observatory, Edward Holden. A meridian telescope like that was designed to measure the positions of stars very accurately with respect to the horizon and the zenith. And so when a star passed through the field of that telescope, it was on the local meridian. And an observation like that, an astronomer can turn that into a very exact time. So basically, they would find the time with an instrument like that, like that meridian circle, and then set the observatory clock from that observation with that telescope. And then the observatory clock was the master clock that was used ultimately for the, to provide time signals by telegraph lines.

Norman Gilliland: All this done by hand? How would they have done these charts?

Jim Lattis: The observing was done literally looking through the telescope, “eyeball at the eyepiece” astronomy and noting, pressing a button really, when the observer saw the star move through there. And that fundamental measurement could be used for actually a lot of different purposes, in addition to just the very practical one of finding accurate time. They would come up with tables of numbers. Let’s say they were using the meridian circle telescope to come up with star positions for something like, they used to do stellar parallax measurements, which gets you distances to stars and things like that. You’re writing all those things down by hand. And that’s just the number that you get, the time that you get from observing. And then the circle part of the meridian circle gives you another number. You put those two numbers down. Those are your observation. And then, there’s a long series of calculations you have to go through to turn that into a position on the sky. And that was the sort of thing that, of course, in those days was carried out completely manually. No, there were no electronic computers or anything to do that kind of work.

Norman Gilliland: And what kind of staff for Washburn?

Jim Lattis: So in the early days, Washburn had a director, and the director was a professional astronomer. And Edward Holden, who we saw at that beautiful meridian circle telescope, was hiring assistants from his courses. He was hiring students, men and women to play a variety of roles in the observatory. In this particular area, era, in the late 19th century, it was very atypical for women to be afforded time observing. It was believed that night work was not for women, and so most time on the telescope actually making those observations was reserved for men. But the student assistants, which included women, they were the ones who were performing those hand calculations on big, long spreadsheets, really taking the observational data that the observer or the astronomer was making at the telescope and translating that into useful data.

Kelly Tyrrell: I’m just wondering what kind of majors these students would have had.

Jim Lattis: Yes, so at the time, there was nothing like an astronomy major [laughs] at the university. Many of these students were, might be science majors, for instance. Just a very generic major. Holden had a joke that, that the I’m sorry, it was Joel Stebbins. He was the fourth director, and he had a joke that women were just as capable as men at astronomy, but probably much neater. [Norman laughs] And probably was very true. But one thing that was somewhat unusual at Washburn and with Edward Holden in particular, is he did have, some of his female assistants were actually afforded time observing. Alice Lamb, for instance, is one of the student assistants that we have quite a bit of record on. And she and her eventual spouse, Milton Updegraff, were student assistants under Holden, who, when Holden left for a different job at Lick Observatory in 1885, Alice and Milton basically kept the observatory running. So between the two of them, they were at the telescope making observations. They were publishing in the publications of Washburn Observatory. And Alice would go on to accompany Milton over to Argentina, actually, where his astronomy career continued. She really desired a career in astronomy, but that did not pan out for her in the era.

Norman Gilliland: Do you have a sense of You mentioned the Lick Observatory, and there were, of course, many others in the country by this time. We get into the late 19th century. Do you have a sense of to what extent they were competing and to what extent they were collaborating?

Jim Lattis: There was a lot of collaboration in the sense that these, the astronomers would always share results. In fact, Kelly mentioned the publications of the Washburn Observatory, which were published for many decades. The patterns of science were shifting in the early 20th century, and astronomers started publishing in journals. But the publications were printed up largely for, in part for sharing results, but in part to have something to trade to other observatories for their publications. And so there was a very active network of these sorts of things, of astronomers sharing data, and then they would specialize in areas that they were well-equipped for. So the Washburn Observatory, for example, was an early specialist in coming up with these stellar parallax measurements that came from that meridian circle. And other observatories, Lick, for example, had different specialties, in spectroscopy, for example. We could say the same thing about Yerkes Observatory. So they had different specialties, and the astronomers had different interests. The competition, maybe was friendly. I’d have to say, yeah.

Kelly Tyrrell: One thing that ultimately set Washburn Observatory apart from some of the other observatories of the era. We’ve talked about Harvard. Harvard really invested heavily in the early 20th century in photographic astronomy. And so, they were using their telescopes to essentially take pictures of the sky the same way the Hubble telescope does today. And they were then looking at those pictures and making observations and measurements there. Washburn made a different choice, and I think Jim can speak a little bit to how that choice was made and what that ultimately led to.

Jim Lattis: In the earliest days, it was these position measurements that we were just talking about, and it did lead to certain applications that, for example, figuring out the orbits of these binary stars based on position measurements, which is very laborious work, by the way, because again, all those observations are done “eyeball at the eyepiece,” and then data reduction done during the daytime. And it resulted in, in some cases in insights into the nature of stars, into the masses of stars and things like that. Very early contributions to what we might now call, what we would probably call astrophysics in terms of thinking about the, the actual physical nature of these things. What’s the mass of a star?

But that style of astronomy was changing very rapidly in the early 20th century, in part because of photography, because astronomers found that eventually they could make observations of star positions more accurately photographically than they could with an instrument like a meridian circle. So, Washburn, if it had followed the patterns that it had in the late 19th and very early 20th century, Washburn Observatory would have been pretty much obsolete by the ’20s, when modern astrophysics started coming in.

But the fourth director of Washburn Observatory came here, actually had been a student at the Washburn Observatory for a year earlier in his career, came here as the fourth director and was experimenting with the electronic measurement of light, and measuring the quantitative measurement of light, which we call photometry, was something that could be pursued either photographically or electronically. And most astronomers were much more comfortable with photographic methods. But the electronic methods could give you much better results, much more accurate results. But very few astronomers were willing to mess around with electronics of the 1920s. Think of a radio from the 1920s. In fact, Stebbins would occasionally say, “Well, think about a radio attached to the end of the telescope.”

This enabled them to do science that nobody else was doing because no other very few other astronomers, I won’t say none, but very few other astronomers were willing to learn the electronics. And Stebbins was, and he also partnered up with physicists to help him develop these instruments. And they were able to come up with science that was very important in the early days of astrophysics in terms of understanding not only the natures of stars, for example, but even the structure of the galaxy.

Norman Gilliland: But if we’re looking at photoelectric photometry, is that Stebbins that we’re seeing still eyeballing through the telescope?

Jim Lattis: Well, no. That’s one of the interesting things I like, that it looks as if Stebbins is looking through the telescope. He’s actually looking at a microscopic meter. He doesn’t see the light from the telescope. It goes into that detector tube. And what Stebbins sees through that little microscope is a microscopic needle that’s creeping across the screen, that’s measuring the microscopic current that comes off of that tube. So he’s not looking through the telescope anymore. It’s not “eyeball at the eyepiece.” It is “eyeball at the electrometer” at that point, but not at the eyepiece.

Norman Gilliland: Now you’re talking a lot about stars, distant objects. Were there interest at all in looking at planets, or are they just too close to be interesting at this point?

Jim Lattis: Certainly, many astronomers looked at planets when they were, say, when Mars was at opposition and relatively close. But actually, planetary astronomy in the 20th, in the early 20th century was kind of a, sort of a poor stepchild. There wasn’t very much science that was, that you could do observing planets.

Norman Gilliland: You could get closer and closer image, but not really learn that much about anything?

Jim Lattis: Well, the atmosphere kind of limits you on how much detail you can see even with big telescopes, and so

Norman Gilliland: The Earth’s atmosphere.

Jim Lattis: The Earth’s atmosphere, right. And so, so it was People did planetary astronomy, but there wasn’t a great deal to be done about that beyond, say, counting moons and measuring the phenomena that you could see. There were some very minor avenues that Stebbins pursued that do amount to planetary observation. But no, for the most part, it was about studying problems in stellar astronomy and the nature of stars. In that period, it was still a mystery how stars produce their energy. How does that keep up for so long, and how long will it keep up? What are the sources of it? So coming to terms with the nature of stars was one thing that Stebbins could derive from the photometric astronomy photoelectric astronomy.

Norman Gilliland: So they gave up looking for Vulcan pretty early on, I guess. [all laugh] Kind of almost legendary search for this planet that may or may not have existed in our Solar System.

Jim Lattis: So there is a connection there at Washburn Observatory very early. But our first director who wanted to do that, James Watson, died too soon to carry out his plans for that, and nobody else followed him up on that.

Kelly Tyrrell: He did build an observatory in the Hill for expressly that purpose.

Jim Lattis: What are the astronomers at Washburn then starting to discover about the nature of star power?

Jim Lattis: Well, so, for example, the trace there, that light curve that shows the way the light changes in what’s called an eclipsing variable star. There’s a plunge in the brightness, which is called the primary eclipse. And then a little while later, there’s a smaller plunge in brightness that’s called the secondary eclipse. Those curves, Stebbins is measuring those with his photoelectric photometer, looking through that little eyepiece and writing down those numbers. But in the case of the eclipsing binary star.

Norman Gilliland: These are stars that are in an orbital movement where one is passing over the other. So that’s the eclipsing part of that.

Jim Lattis: Exactly right, yeah. So when the one, when the dimmer one passes in front of the brighter one, you get a big dip. So this was known to be that there were stars that would do this. But the accurate measurements that Stebbins could make allowed him to derive things like the relative sizes of the stars. And that diagram that you see there is one that he published, showing the relative sizes of these two stars. And if from studying the orbit of the stars, you get the masses, then the masses and the sizes give you the densities of stars. So this is the beginning of understanding the physical characteristics of stars that would lead to, not too many years later, by the mid 1930s, the conditions that existed within stars were enough that astronomers could come up with their, and physicists could come up with their theories about thermonuclear reactions going on in stars, and that being the energy source of stars. But you’ve got to know all those basics, mass and density and things like that, before you can begin coming up with your theories about where the energy comes from.

Norman Gilliland: Are they looking specifically at galaxies at this point?

Jim Lattis: So galaxies were barely even a concept in the early 20th century. The word galaxy literally meant the group of stars that we live in, and what we now think of as other galaxies were little smudges, little swirly smudges out there in the sky, and people didn’t really know if those were things as big as our galaxy or if they were some other type of object. But understanding the star system that we live in, they would have called it the stellar system, which we would now call our galaxy, had a very important development here at Wisconsin. Again, from Stebbins’s photoelectric photometry, because he was able to determine distances to objects that showed how big the galaxy was and show that the galaxy actually contains a lot of matter that isn’t stars. And he could talk about how that affects the measurements and how much matter that is. So all of that stuff from that photoelectric photometer on the Washburn telescope.

Kelly Tyrrell: He’s quoted as saying that we “shrunk the universe” because by being able to take those measurements, there had been lots of conjecture about the size of the galaxy. And Stebbins and scientists at the time were able to establish the galaxy is actually smaller than we thought it was.

Norman Gilliland: Did that impression hold? Because it seems to me it keeps getting bigger.

Jim Lattis: [Jim laughs] No. Actually, the number that Stebbins estimated for the size of the galaxy is very close to the number you’ll find in modern intro astronomy books. About 100,000 light years in diameter.

Norman Gilliland: Of the galaxy.

Jim Lattis: Give or take. Yeah, about 100,000 light years in diameter, the Milky Way galaxy.

Norman Gilliland: Well, we started seeing these other galaxies. And by the way, can we see any galaxies with the naked eye and just not recognize them as such?

Jim Lattis: Sure.

Kelly Tyrrell: The Andromeda galaxy is one of the easiest. To the naked eye, it looks like a smudge in a dark sky, but that is a galaxy that is visible to the naked eye. And our closest neighbor, galaxy neighbor.

Norman Gilliland: And now we have good distances for that kind of thing, but in those days, they didn’t really have much idea of the distance of these things or their size. You’ve got to know one or the other to figure that out. And so it was very much up in the air. Just what was the nature of these other things out there that we now call galaxies? They called them nebulas. Spiral nebulas is what was the common term.

Jim Lattis: Did they have a sense at all at how galaxies are formed? Are they seeing formation of galaxies at this point?

Jim Lattis: No, that’s a much later sort of thing. The ideas of galaxy, theories about galaxy formation and then galaxy evolution, and these days, a very important thing is galaxy interaction.

Norman Gilliland: Sure.

Jim Lattis: Yeah, those were No, those were, those would come later, well after the Stebbins era.

Kelly Tyrrell: A lot of the science that was the groundwork for that science was being laid here and elsewhere. But really, as Jim mentioned, the pivot to the photoelectric effect and really looking at electric astronomy really helped move the astronomical field in that direction. But importantly, it helped establish Wisconsin as a place where innovative technologies and instrumentation were being developed, which then also led into additional pioneering science.

Norman Gilliland: Have they seen any collisions of galaxies at this point? And if so, what was going on?

Jim Lattis: No, in that period, no one was, as far as I know, was thinking about colliding galaxies. Certainly, there are many cases now. There’s lots of that. That’s a very important process to understand. And it would appear that most galaxies evolve in part by absorbing other galaxies colliding with them and eventually merging together. So that’s pretty well understood and constantly being studied by modern astronomers. But that’s a much later thing than what we’re talking about there in those days.

But as Kelly said, it did, that kind of work and the development of that technology here did set up Wisconsin astronomers to carry on this kind of research, much of which is done with space-based research. The specialty here in electronic astronomy, we could call it, set up Wisconsin astronomers for the early days of the space age and using early space technology and satellites to do observations in space. The way much of this, a lot of those great pictures that you see of colliding galaxies come from the Hubble telescope. And Wisconsin astronomers were developing the predecessors to the Hubble, and even pieces of the Hubble have been made, have been done here.

Norman Gilliland: In that context, what are electronic astronomical detectors detecting?

Jim Lattis: They’re sensitive to light, both in the optical, but also in the ultraviolet and also in the infrared. The thing about the ultraviolet, for example, is that we don’t get much of that, hardly any of it on the surface of the Earth, just enough to be a nuisance for those of us with light complexions, but. [chuckles] Yeah, sure.

But the ultraviolet light that would be useful for astronomers doesn’t make it through the Earth’s atmosphere. You’ve got to be above the Earth’s atmosphere. So those kind of electronic detectors make it possible to detect light that we couldn’t observe here from Earth. But we do have to send those electronic detectors out into space. And so, when the early days of the space age came along, which basically made it possible, then you put a if you can You got a rocket big enough to put a satellite in orbit, you can maybe use that to do some astronomy. And Wisconsin astronomers were well set up to build instruments that could be launched into space and used for astronomical observations. So we were some of the pioneers of space astronomy here at the University of Wisconsin.

Norman Gilliland: And that gets back then to Hubble and some of its contemporaries in terms of extraterrestrial astronomy. Is that what you would call it?

Jim Lattis: Yeah, we usually just say space astronomy, yeah. [all laugh] All right.

Yeah, right. So the, I mean, you know, Sputnik was launched in 1957, and NASA was formed, not coincidentally, in 1958. [laughs]

Norman Gilliland: Yeah, in a kind of a rush.

Jim Lattis: In kind of a rush, yeah. NASA began funding astronomers to figure out what they could possibly do with a satellite. And again, the Wisconsin astronomers were very well set to explore that, because operating an electronic detector in orbit is way easier than operating a film camera in orbit for any number of reasons. And so, yeah, so that led to a pretty long line of space instruments coming from Wisconsin ultimately, in building, of course, a photometer for the Hubble Space Telescope. And in fact, there’s the instrument being built for the Hubble telescope. There’s the Hubble telescope, but then also the instrument that was our photometric package there. The astronomer there on the left is Robert Bless, who developed that instrument, and his project manager, Evan Richards. They and their teams produced that instrument, which was launched with the Hubble. So the reason there’s a Wisconsin photometer on the Hubble telescope is because Joel Stebbins came here in the 1920s.

Norman Gilliland: That’s quite a long reach for Joel Stebbins. [Jim chuckles]

Hubble, there was sort of a little bit of a joke going around about Hubble at first that what, it needed bifocals and needed to kind of make some adjustments once it was already out there. How did that relate, if at all, to Washburn?

Jim Lattis: Right, the problem with the Hubble telescope when it was first launched was the mirror had not been correctly made. [chuckles]

Norman Gilliland: It had a

Jim Lattis: Yes. Problem.

Jim Lattis: The main mirror had a, had been incorrectly made so that it produced out-of-focus images. And so, yeah, that’s the joke about putting glasses on the telescope to correct those out-of-focus images.

Norman Gilliland: Thankfully not a Wisconsin error.

Jim Lattis: No, [chuckles] certainly not. But we did suffer because of that, because our instrument then had to be used with those very imperfect images. And, but it badly affected all of the instruments on the Hubble. The saving thing, the saving thing for NASA was that those instruments could be replaced. And so, other generations of instruments were installed by subsequent visits of space shuttle astronauts. And so the Hubble operates up to full spec today. But that was an awkward beginning, but not our mistake.

Norman Gilliland: A lot of details to keep up with there. Hubble is in orbit?

Jim Lattis: Orbit around the Earth, that’s right.

Norman Gilliland: And that’s how the space station could kind of just intercept it and …

Jim Lattis: Well, yeah, the space shuttle.

Norman Gilliland: Space shuttle?

Jim Lattis: Yeah, that’s right. You, they would launch the space shuttle into, in such a way that it was in the same orbit as the Hubble, and then it could approach and the astronauts could work on the telescope up there.

Norman Gilliland: Any risk once you get something like Hubble up there, that the technology is going to outpace it?

Jim Lattis: That’s why it was designed to have replaceable instruments. Some of those instruments on the Hubble today are third-generation instruments. And yeah, they’ve taken advantage of advances in technology for better instrumentation all the way along.

Kelly Tyrrell: It’s been a lot of innovation since the ’90s when Hubble was first conceived.

Norman Gilliland: What This gets into that question that astronomers inevitably get. But here it is, I mean. How is something like Hubble, a big project, expensive project, long, ongoing project, what’s its actual mission in terms of “practical” things? Or is it all just out of scientific curiosity?

Jim Lattis: Well, certainly the scientific curiosity is what drives us. That’s the, you know, finding the answers to these questions that we want to understand how/why are there stars and how do they shine, and where are we and what’s our relationship to the rest of the universe? Those are back there. But finding answers to those are far from the only benefits that we get from that kind of work.

Kelly Tyrrell: That’s true of a lot of basic sciences. It’s driven by curiosity, just a human desire to know more about the world, or in astronomy, the universe around us. But we don’t always know at the time that we embark on that science, what the technology or what the findings or the innovations might lead to. I’m really inspired by astronomy because I think not as an astronomer. I am not an astronomer, but, that it really just taps into this essence of humanity, right? This deep desire that we all possess to understand, but that also helps us move forward as a species.

Jim Lattis: But that said, many of the things that astronomers have discovered about the universe do have direct practical implications on the Earth, notably things like fusion energy, the whole understanding of that sort of thermonuclear chemistry that goes on, comes out of investigations into the energy sources of stars to then understand how that can be applied here on the Earth for everything from hydrogen bombs to someday electrical energy from such things. The drive to understand the energy processes of the stars is behind the investigations into that sort of physics. So there are a number of those sorts of things. You can go back to things like we mentioned earlier, the timekeeping or celestial navigation. In the early days, those were strong motivations for astronomy because nations needed celestial navigation. They needed this for commerce. And navies always needed the sort of thing. And you needed some astronomers who could help your ships navigate long before there were GPS systems. So you have lists of practical applications and sometimes practical outcomes from these sorts of things. But none of those are really why we’re doing it. You never know where the benefits are going to emerge. And so, you have to kind of keep on working on the basic problems and asking the basic questions, and you can hope that they lead to some practical things, and they often do.

Norman Gilliland: A good, honest answer. That’s right. I mean, the priority is just because we wanna know.

Jim Lattis: I think that’s right.

Norman Gilliland: And what may come out of that could be a blessing. What do we learn about fusion, then, in these explorations of the universe? So fusion being sort of the Holy Grail, isn’t it, of energy production here on Earth?

Jim Lattis: Sure. Fusion happens in a lot of different ways in the astronomical context, in terms of the evolution of stars. The evolution of stars is really a matter of the evolving conditions in stars that produce different phases of fusion, first of hydrogen into helium and then helium into heavier elements and so on, and we see this happening out in the universe around us. Those sorts of things are probably not first in the mind of the engineers who are designing fusion reactors. That sort of thing is pretty well understood in the laboratory by now. And they have very specific goals. So I don’t think there’s much of an astronomical connection anymore, except that this, that was the motivation for understanding that sort of physics in the very beginning. So the fusion is a huge laboratory and engineering problem now. And we do that on the UW campus too, fusion research. But again, it has little to do with the astronomers these days.

Norman Gilliland: With a telescope like Hubble out there, a couple hundred miles orbiting well past the Earth’s atmosphere.

Jim Lattis: Yeah.

Norman Gilliland: Or just past. [all laugh]

And getting a good, clear look at things that we could not see from Earth. What is the role of terrestrial-based observatories like Washburn?

Kelly Tyrrell: Well, so Washburn these days is a pretty small observatory. [chuckles] So Wisconsin astronomers have much bigger telescopes to draw on now.

Jim Lattis: And as we alluded to earlier, the conditions here in Madison are no longer conducive to productive observation. Certainly, we can observe.

Kelly Tyrrell: Atmospheric interference.

Jim Lattis: Yes. So you look for arid mountain tops and things like that. That’s where you want your telescopes these days.

Kelly Tyrrell: You want it high and dry and dark.

Jim Lattis: But the Hubble is, you put it correctly to say that its advantage is that it’s above the Earth’s atmosphere. It’s not an especially large telescope. It has a mirror that’s 2 1/2 meters in diameter, which is way bigger than the Washburn telescope. But Wisconsin has a ground-based telescope out in Arizona that’s 3 1/2 meters in diameter. The Hubble’s advantage is not in its size, but in its positioning above the Earth’s atmosphere. So the Earth-based telescopes have their role in being a lot bigger, in collecting a lot more light and being able to image dimmer, more distant objects and phenomena than a telescope like the Hubble can. Also, there’s an awful lot of There have never been enough astronomers to look at everything in the sky. And so, the Hubble keeps busy observing one thing after another. But the research programs that astronomers can come up with way exceed the available observing time, even with something like the Hubble. And so observatory ground-based observatories all over the world are pursuing various sorts of research programs that can’t be carried out with the time that’s available just on that one, on the Hubble telescope.

Norman Gilliland: I guess they have the advantage of being a little bit more accessible than Hubble.

Jim Lattis: Well, yeah, there’s that too, there’s that too, yeah.

Kelly Tyrrell: Although these days, astronomy isn’t done “eyeball at the eyepiece” like it was at Washburn. So data comes in, it’s electronic. And so, researchers can just access these troves of data sets now to essentially mine any question they wanna ask. The competition comes in and actually getting time on these ground-based instruments to point the thing at the object you are interested in looking at.

Jim Lattis: But your comment about accessibility, though, is well-illustrated here. There are some of our people working on an instrument before it goes to a ground-based telescope. In that case, that’s not a space instrument. In that case, you can get it as close as right in your laboratory, but then you do still get to work on it once it’s on the telescope out there, and you can even iterate. We can make better ones or we can improve that one. So access is an, especially in instrument development, is an important advantage as well. The space stuff, once you get it up there, it’s pretty much there. You don’t get it back usually.

Norman Gilliland: But are you saying then that a telescope, such as the one in Chile, or even the UW one in Arizona, can actually see farther than Hubble, because they’re so much bigger?

Jim Lattis: Well, yeah, the way to put it would be that the bigger the telescope, the dimmer the …

Norman Gilliland: Light source?

Jim Lattis: The dimmer the light source it can pick up, yeah. And that could be owing, could be dim owing to distance, could be dim owing to being small, even if it’s nearby. So, yeah, so greater light-gathering power is what we usually call it with the bigger The bigger telescope has the greater light-gathering power. The Hubble, again, has the advantage of being above the Earth’s atmosphere, which degrades the images that ground-based telescopes can create. So it gets a nice, clear view of the sky. Another advantage of being in space, the Webb telescope that we talk about a lot these days.

Norman Gilliland: Famous now, yes. See a lot of images from the Webb.

Jim Lattis: But its specialty is detecting light that doesn’t penetrate the Earth’s atmosphere at all, in that case, in the infrared. So early Wisconsin space astronomers were doing, were exploring the ultraviolet. And so getting your instrument in space, whether it’s infrared or ultraviolet, is another really important reason for developing those kinds of instruments.

Kelly Tyrrell: And this telescope here is the Southern African Large Telescope. And UW-Madison is the largest of a consortium of partners that basically help keep this telescope operational in South Africa. It’s in the desert, the Karoo. This is a 10-meter telescope, which means it just has a massive, massive set of hexagonal mirrors that act as a giant light bucket, right? So it’s collecting as much light as possible. And 10 meters is a really large set of mirrors. And it also has an instrument on it in the near-infrared. So it can’t get infrared. But UW scientists actually worked with South African scientists. But here developed that new instrument that went to the telescope in 2022.

Norman Gilliland: These wonderful pictures that we’re seeing online now everywhere, these fantastic pictures that are inconceivable from somebody’s naked eye standing in a clear desert climate, cannot imagine these clouds and the colors and the …

I was gonna say galaxies, but galaxies of galaxies of stars. Are those actual photographs? What is the technology? What are we actually seeing? Is it a computer simulation?

Jim Lattis: Well, certainly, generally speaking, we’re seeing images created by telescopes of different sorts. But sometimes in the case of, say, an image from the Webb telescope, those observations were made in the ultraviolet, sorry, in the infrared, infrared or far-infrared. And so, when they put in colors and things like that, they’re basically coding. They’re assigning codes of certain colors to correspond to certain wavelengths that we can’t perceive at all. So those colors are sometimes called scientific colors or false colors. But, so those sorts of things are not an image in the sense of what you would see in the sky if you could be out there at the Webb telescope or something like that. But the ones that are created in the visual from the ground sometimes are created the same way. Or sometimes, they’re created in such a way that maybe if you had eyes that were 10 meters in diameter, that maybe it would look like this. That’s all kind of silly in a way. What the real power of these things is that astronomers can understand the physical phenomena. So when you see, for example, a lot of pink in an image like that, and this is an image from the Rubin telescope.

Kelly Tyrrell: Vera Rubin.

Jim Lattis: Yeah. Which was a very recently brought online. That pink there is telling you where hydrogen is glowing. And so, an astronomer can look at an image like this, and from the nature of the image and the distribution of wavelengths at one point or another, you might think of it as distribution of colors, but it’s way more specific than that. And they can understand the composition and the conditions, and even things like the motions of the various parts of an object like this. That’s a vast star-forming region.

Kelly Tyrrell: The pink one is the Lagoon Nebula. And the bluish pink at the top there is the Trifid Nebula.

Norman Gilliland: The Trifid Nebula. [all laugh] Yeah, that sounds like a science fiction movie from the ’60s.

Jim Lattis: Yeah, these are complex. Maybe that’s where it came from. These are complexes of dust and gas there where stars are forming. And star formation is something that’s very interesting for astronomers to understand because ultimately, planets come from that, too. And ultimately, we come from planets.

Kelly Tyrrell: As Carl Sagan once famously said, “We are all stardust.”

Jim Lattis: Right. So understanding that stardust is understanding ourselves there, so

Kelly Tyrrell: Recycled dust, that’s what it comes down to. It’s a little depressing, but exciting too.

Jim Lattis: Original sustainability. [all laugh] Yeah, right.

Kelly Tyrrell: Speaking of images, this is actually not just one image. This is 678 images stacked together that were taken over the course of seven hours to yield a picture of these two.

Norman Gilliland: So a composite?

Kelly Tyrrell: Yes.

Jim Lattis: That’s a very wide field of view. A typical telescope The Rubin is specifically designed to do this, to have a very wide field of view. And normally, to have that kind of field of view, a typical telescope would have to make many little pieces and stitch ’em all together, and that would take days or worse.

Kelly Tyrrell: And lots and lots of computing power to make happen.

Jim Lattis: But here, the Rubin can do it in basically minutes.

Norman Gilliland: Are we talking AI here?

Jim Lattis: Not in the production of the image.

Kelly Tyrrell: Yeah, probably just a lot of high-power computer science, that …

Jim Lattis: Data analysis.

Kelly Tyrrell: Mm-hmm.

Jim Lattis: Yeah, well, yeah, there’s a huge amount of computing going into making those images, but I don’t think you would call it AI. Now, the AI couldn’t come, could come in when astronomers have enough data to look at, say, different examples of star-forming regions, and then ask AI to try and generalize about what are the, I don’t know, what are the essential conditions that go into these sorts of things or something like that. It might come into the thinking about the problem down the road, but no, not the production of the image per se.

Kelly Tyrrell: Or asking AI to analyze patterns that might be missed by a human observer.

Jim Lattis: Well, as long as we’re talking about star formation, can you give us a timeline for forming, I don’t know, a yellow dwarf or red dwarf or whatever it might be?

Jim Lattis: Well, it sort of depends on where you start. So out there in that star-forming region, there are knots of molecules and gases that are called molecular clouds. And those clouds, under circumstances that There seem to be a number of mechanisms that can trigger this. The cloud can begin to collapse on itself gravitationally. So if you start the stopwatch running then, then understanding how fast that can happen is something that astronomers are very interested in. And studying large clouds like this, because you can see finished stars in there and you can see these cold molecular clouds in there. And it varies probably on the size of the cloud and how big the star is. But it happens over a period of hundreds of thousands to a million years, which is fairly fast.

Norman Gilliland: I was gonna say, “To make a star, a million years?” Yeah, right. Pretty good. It’s on a But then where do you stop the stopwatch? Because they’re never quite done. Do you stop it when it’s got a planetary system and it enters what astronomers call the main sequence? That’s probably where you could agree to stop it. But you’ll We actually understand those sorts of things relatively well now, not The problems are far from solved. But compared to 100 years ago, we’re able to talk about these things in terms that the astronomers of Stebbins’s era had no clue about. In fact, even the very idea of star formation and star and planet formation 100 years ago, this idea of the collapse of clouds which had been tossed around, was actually on the outs. People didn’t think that was a very good theory. And there were some competitors. So it’s in the past hundred years, we’ve come a tremendous distance in our understanding of things like star and planet formation, which is far to say, not to say anything like we’re close to being done. But we have such powerful insights into that now that it makes everybody want to know more and understand better where, say, planetary systems come from.

Kelly Tyrrell: And we’re seeing more and more. It seems to me we’re seeing we’re finding more, even so-called Goldilocks planets now.

Jim Lattis: Oh, yeah, well, I mean what’s it been, 25 years? How long have we had exoplanets? It’s finding any star systems beyond the Sun is a relatively recent thing.

Norman Gilliland: Is that done through transits, where you can see them crossing the face of a star? Or is there more analysis to it?

Jim Lattis: Well, certainly, that’s one way. Yeah, that’s been one of the more productive methods of finding exoplanets. There are other techniques as well that are less direct than actually seeing that eclipse. But the era of direct imaging of planets around stars is, the Webb has been able to do this in a couple of cases. We may be on the verge of that, of seeing these things, at least a few of them directly around stars. But very often, when you mention a Goldilocks planet, you’re looking for a This is a planet that’s at the right distance from its star, that it can have liquid water on it. That’s usually what the criterion is. And there will inevitably be more of those just because the number, the total number of known exoplanets, whether they’re Goldilocks planets or not, is going up. So, yeah, there are more and more of those. But the planet detecting programs are going great guns. And that’s a very exciting thing these days for astronomers too.

Kelly Tyrrell: One of the things that has long set Washburn apart from so many other observatories is the role it has in public engagement. And can you give us kind of a history of that and what that public engagement has produced, other than just people fascinated by looking at stars?

Jim Lattis: So when Edward Holden got to the observatory as the second director, he decided that he was going to maintain a public observatory. So the observatory was built with an infusion of money from Governor Washburn. But also, Washburn helped Bascom ensure that the telescope was supported by the state legislature. So at the time, it was at the amount of $3,000 per year. The state supported basically the science that happened at the observatory. Laugh because I think it’s the first example of public-private partnership [laughing] at UW-Madison or the University of Wisconsin. But Holden really valued the idea of a public observatory. And so, so long as the observatory wasn’t in use for, specifically for a scientific mission, it was opened to the public on, I think, the first and third Wednesdays.

Kelly Tyrrell: From the very beginning.

Jim Lattis: From the very beginning.

Kelly Tyrrell: Wednesdays was the day from the beginning.

Jim Lattis: Yes, and it continues.

Kelly Tyrrell: From 1881.

Jim Lattis: Yeah, to this day. So from 1881 until today, Washburn Observatory is a place that people can come and look through the refractor.

Kelly Tyrrell: And then, of course, there have always been special occasions. When Halley’s Comet came by in 1910 and people were clamoring to see it.

Jim Lattis: And this happens today too, when there’s some

Norman Gilliland: Well, it came back in 1985, right?

Jim Lattis: It did, although that was not so good as we couldn’t really see it as well as they could in 1910. So I don’t think anybody tried to see the Halley’s Comet with the Washburn telescope. Somebody might have, but

Norman Gilliland: An atmospheric difference?

Jim Lattis: Mostly orbital difference.

Kelly Tyrrell: I mean, it was just way

Norman Gilliland: Oh, just a different position.

Jim Lattis: Favored southern observers, way over northern observers in the 1986. But the point is that the When there are these things of enormous interest, we still open up the observatory extra nights, and they had to open up lots of extra nights during 1910 when there were, when Halley’s Comet was in the press and in the sky. And this still happens from time to time. But yeah, the regular nights are the first and third Wednesday nights, weather permitting, of course. And then in recent years, the astronomy department has been doing every Wednesday night, June, July, and August. So once again, weather permitting. So this is a long tradition here. And it’s, you asked about in addition to just letting people look through the sky, it’s been great for the students and the astronomers, especially our graduate students who run that program now, to have an aspect of teaching astronomy and then that way, to meet the public and answer their questions and help them go back to “eyeball at the eyepiece” astronomy and enjoy the sorts of sights there are to see in the sky.

Norman Gilliland: So if I were to stop by Washburn on some Wednesday evening, what would I most likely get to see?

Jim Lattis: Well, that would, that’ll vary with the time of year and what sort of things are available. If there are bright planets, then those are very popular. Everybody wants to see Saturn or Jupiter, or if the Moon is up. And the whole evening can go by and you never look at anything but whatever planets and the Moon are up there.

Norman Gilliland: Regular planets.

Jim Lattis: Yeah, well

Kelly Tyrrell: Well, some of Jupiter’s moons, and that’s always fun to count how many you can see at any given time.

Jim Lattis: So those would be typical. But then, once you get past planets or if you don’t have any planets that night, which certainly happens, the telescope is very well-adapted to things like binary stars, star clusters, and some bright galaxies. The sky here in the city is too bright now for galaxies to be too much. Or nebulas like the image we had of the Lagoon Nebula or the Trifid Nebula. Those are low in the south for us, but we can pick those up. To the eye, they don’t look anything like those images. You don’t see any colors in them or anything along that line, but we can introduce the people to a wide range of astronomical objects with that fine old telescope.

Kelly Tyrrell: There’s a wonderful juxtaposition of Washburn Observatory that I don’t think you would find anywhere else in the country, maybe not in the world, which says so much about astronomy, or at least people looking at the sky, looking at the stars and the planets over a long period of time. And Washburn is actually on a hillside that had three effigy mounds on it, which clearly had some sky significance to the builders. And here it’s right next to Washburn. What kind of a sense do you get when you go up there and see that effigy mound right next to the observatory?

Jim Lattis: I think it’s a really powerful reminder that we’ve, as long as we’ve been on this earth, we’ve been really curious about the night sky and the connection between earth and water and the heavens. I think it’s a really, important thing for us to remember that, though we’ve talked about sort of the more recent modern innovations in technology and in science, that as long as we’ve been humans, we’ve been fascinated by the stars.

Kelly Tyrrell: It is, as you say. It’s a wonderful juxtaposition to know that people a thousand years ago, or whatever the date of the mounds is, were up there on that hill. And it was a special enough place to them to build those mounds. And they were, must have been aware. All human cultures have been fascinated by the sky. And so it’s been a special place there for that distant culture as well as our own.

Jim Lattis: Human curiosity.

Kelly Tyrrell: Modern, modern.

Jim Lattis: Human curiosity carrying over the millennia.

Jim Lattis: Yeah.

Kelly Tyrrell: And you can see it right there on the hill at Washburn Observatory.

Norman Gilliland: Jim Lattis and Kelly Tyrrell, it’s been a real pleasure looking skyward with you.

Jim Lattis: Thank you so much, Norman.

Kelly Tyrrell: Thank you, Norman.

Norman Gilliland: They’re the co-authors of the book Chasing the Stars. I’m Norman Gilliland, and I hope you can join me next time around for University Place Presents.

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