Monsignor Bouchet’s telescope is coming back to life! Who is Bouchet, you ask, and what is the story of his telescope? Msgr. Michael Bouchet lived from 1827 to 1903. He was rector of the Cathedral of the Assumption in Louisville, Kentucky in the late nineteenth century, and Vicar General of the Louisville diocese. He had a refracting telescope of 4¼ inch (108 mm) aperture, manufactured by A. C. Schuman of Louisville.
That telescope still exists. It is housed in the Archdiocese of Louisville’s History Center, which is located across the street from the Cathedral. That’s the telescope (and its very sturdy wooden box) at below left, and Bouchet at right.
Msgr. Bouchet and his telescope were the subject of a post here, way back in 2016 — CLICK HERE to learn all about the Bouchet telescope.
At that time, Tim Tomes, the archivist of the Archdiocese (at right in the photo below) and I talked about how it would be great to get Bouchet’s scope functional again. But it had no mount. Its focusing mechanism was all locked up. We had other stuff to do. The idea went nowhere. Tim and I did not run into each other for a long time.
But in March of last year Louisville was installing a new archbishop, Shelton J. Fabre. At a special vespers service at the Cathedral the day before the official installation, Tim spotted me and came over to say hello. Then he said something about how he really wanted to do something with that telescope. At this point, I had retired from my college and was doing a lot more work for the Vatican Observatory. That meant I had more flexibility to work on something like Bouchet’s telescope. And so this time the idea gathered some momentum, and in December of last year I began to work on the telescope — while Tim hoped hard that I knew what I was doing!
The telescope’s main problems (aside from having no mount — we have no idea what happened to the mount Bouchet might have used) were the focuser and dirt. So the first thing I did was work at taking stuff apart and cleaning it. I have plenty of experience with telescopes, and I’m mechanically apt, but still, a telescope of 130+ years of age was new territory.
I had two main concerns in working on this old scope. One was that most of the parts were brass, including screws. Some of those screws were very small, and quite a few were stuck. Brass is a much softer metal than steel. If you put much of a twist on your screwdriver when turning a stuck brass screw, you will chew up the screw. So I had to make sure I had good-fitting screwdrivers, lots patience, lots of twisting gently with gentle tapping, and lots of penetrating lubricant.
That lubricant points to the other main concern. Things needed to be cleaned and lubed, but the cleaning and lubing had to be done with an eye to the future. If there is lubricant within the telescope tube, and if that lubricant gives off vapors, even slowly, then over a period of decades (and there is no reason that this telescope will not be around for another 150 years or more) those vapors will deposit gunk on the optics. I did not want people working on the scope in the year 2082 to be muttering under their breaths about some idiot who, some time back in the past, gunked up the inside of the telescope through the use of bad lubricant.
I got some good advice through the HASTRO on-line history of astronomy discussion group. Paolo Del Santo of the Museo Galileo in Florence, Italy took particular interest in the telescope. He urged me not to mess it up — and not to try to make it gleam like it was new (or, as he said, like it was actually just a newly manufactured replica of an old telescope). Be happy with it looking old, he said.
With patience, the old telescope came apart. As you can see from the picture at below left, the telescope tube is blackened on the inside to reduce reflections. (The middle picture shows the focuser end and the interior disk that holds the focuser drawtube; the right picture shows the main lens, eyepiece parts, and the focuser knob.) The tube is also well baffled for the same purpose. But a good bit of the black had flaked off over the decades. Once the tube was empty, it was simple to tip it up on its end and slap the outside with my palm — the loose black stuff fell out readily.
Dirty optics, mostly the eyepiece and finder, cleaned up well with water and a soft rag. Well, the eyepiece lenses did, at any rate; the finder lenses were very small and really a mess. Happily, the main lens was in good shape, except for black stuff, which blew and shook off easily enough.
The focuser was tough. It was attached with tiny, stubborn screws that only yielded to WD-40 and hours of gentle tapping-plus-twisting. The images below show the focuser end of the tube disassembled. The focuser is a lousy design — it uses a rack-and-pinion gear, internal to the telescope, to move the focuser’s drawtube.
The focuser is inherently weak, because the pinion gear is mounted on a stalk, as seen below. And of course everything is all brass. Given this weak design, the focuser can’t take any force, because if force is applied then stuff will just flex and the gear will jump. Everything has to be really well-lubricated. But the focuser is internal, so the lubricant will be internal, too. And as discussed above, if the lube gives off vapors, the optics will gunk up.
(An interesting feature of the focuser is that the drawtube seems to be made of cast-off materials, pieced together from other bits. On one bit, visible in the image above right, it says “St. Catherine” — the Monsignor had a truly Catholic telescope!)
The knob and pinion gear would not budge at first, but WD-40 cleaned and freed everything. “Superlube”, which is very stable (thanks Paolo) made everything move well. But there was a lot of play in the rack-and-pinion, and lots of gear jumping, even still. So my wife sewed a variable-thickness wool felt bushing that fit around the existing bushing and helped keep the pinion engaged with the rack!
The felt bushing works well. No more pinion gear jumping. This is still not a great focuser. It is inherently coarse in its action and prone to flexing. But it works now as well as it ever has — probably better, since Bouchet and Shuman did not have Mrs. Graney around! (Or Superlube, either.) The video below shows the focuser in action. Note the tiny brass screws that were such a challenge.
The eyepiece, seen below, had its own flaws. It is a two-lens affair. Once it is removed from the focuser it separates into two pieces, one holding each lens. Here you can see at left the smaller lens that is near the eye, and the larger lens that is more interior to the scope at right.
The part that holds the interior lens is, of course, brass and rather shiny. It creates all sorts of reflections if the eyepiece is used to look at a bright object. Here I added another improvement to the telescope (the first being the wool bushing) — a liner of black paper in the eyepiece lens tube. The images below show the unlined lens tube (left), the lined tube (middle), and the eyepiece in the focuser (right). The glare reduction is noticeable in the two photos but, in fact, the camera compensated somewhat and to the eye the difference is more dramatic than the photos show.
When everything was properly cleaned and Superlubed, everything went back together… and the telescope worked! When set on a table and pointed out a window, it gave nice views of nearby cars and buildings. The images it gave were not what you would see with a modern instrument — the field of view was pretty narrow, for example — but they were not bad.
The real test would be the sky. But to try the telescope out on the night sky required a mount. That story will have to await another day….