on a Calver #2 pedestal observatory equatorial
The Peridier 12.3" Calver,
Shown in the University of Texas Bee Caves Observatory, outside of Austin.
This George Calver 12.3" telescope has quite a history. I acquired it from The University of Texas, McDonald Observatory. It was used for teaching Astronomy classes, public star parties, and a local astronomy club used it. While at U.T., it was also used by de Vaucouleurs, and it was transported to Africa to view a total solar eclipse. Before that, it belonged to Julien Peridier, who had an observatory in Le Houga, France. While at the Peridier Le Houga Observatory the telescope was involved in research projects including a NASA-supported five year study of the Moon and planets. It was also used by The United States Air Force to observe the occultation of Regulus by Venus. Further research on this telescope is ongoing.
There is a book "Harlan's Globetrotters - the Story of an Eclipse" by David S. Evans and Karen I. Winget. This book is about a group of astronomers that goes to view an eclipse in Africa (I don't want to spoil it for you by telling too much) but the point is, they took this telescope to view the eclipse.
This telescope is on a MASSIVE Capstan type equatorial mounting, a Calver #2 pedestal observatory equatorial mount, which has a 4" solid steel Dec. shaft, and a 16.75" Byers worm drive. Unfortunately, like a lot of these old scopes, it had sat unused for a while. The bearings needed to be replaced, everything was out of alignment, and the whole thing had several coats of paint on it. The outer layer and parts of the underlying layers were flaking off. There was no drive corrector or any motor on the Dec. portion. All these things and more are being addressed, including dozens of holes in the tube from where modifications were made, accessories were mounted, temporary mirrors were used while the Calver was being resilvered, and large holes from where different focusers were used. One thing that made restoration difficult is (this is mentioned in the book) the telescope has been owned by several people, used for many different purposes, and apparently modified several times for various reasons. Arguably, no concern was given to using the same thread pattern of bolts. It is therefore a mixture of Metric, Whitworth, SAE, and apparently even some custom made bolts/nuts.
Crane lifting the tube from the observatory at Bee Caves onto my trailer
Tube, pedestal, and equatorial head in shop just after bringing it home
Equatorial head with 16.75" Byers drive
Original worm drive and wheel
Heavy duty mirror cell
Outer end of mirror cell
Showing several places where focusers were attached, and other small holes which had a mixture of rivets, bolts, weld, and lead.
I filled most of these by simply installing short brass bolts and nuts, and made a plate for the focuser.
Rotating ring assembly
One of the cracks in the ring assembly
Both rings were cracked on both sides - what was holding the tube on?
Under the "live and learn" category, I took the two rotating rings which were broken, to a shop to have them welded. They had been brazed in the field, and you can not weld over braze, so it all had to be ground off. I explained very thoroughly about how these pieces worked, and the accuracy needed. He said he understood. A few weeks later I brought the two pieces home and found they were in no way useable. I expected to have to clean the weld from the step, but somehow he had egg shaped them, along with bending or warping. It took quite a while to get them to where I could even set them up on the milling machine table. I could not center them and mill the step, as they were so bad there was not 3 places true enough to center from! I finally cut a sheet of stiff paper the approximate diameter, centered it as best I could, and re-milled the steps.
Milling the step for the rotating rings, after having the rings welded.
Milling the slot so all 4 bolts can be used and the mount can be adjusted. The scope came with a wedge made for Houston, but also came with a spare. I took the spare and made it fit my location. The bolt holes did not perfectly line up, so I milled them out to fit. You can not tell from this photo, but this was a difficult cut, as everything is on an angle!
First set of inner rings finally installed correctly. The rolled and riveted steel tube is not exactly round, so originally these inner rings were custom shaved, trimmed, shimmed, and filed down to make them true on the outside, to fit the rotating rings. Through the years, many things happened to the tube. By the time I got ready to put them back on, it was a nightmare. They were thin in places that they should be thick, vice-versa, new and old holes were everywhere, so they had to be totally refitted.
Just prior to installing the tube
Delicately positioning the tube.
"G. Calver Jan/97 Linscott Ramsgate Mar 1889".
There are several other signatures, from people or businesses that resilvered the mirror.
DEC drive - needed a little attention
UPDATE - FEB 2008
More pictures will be added when it warms up!
The restoration is mostly complete, only some detail work needs to be done. Just a short side note: This telescope came with a Troughton and Simms transit, which I also have restored. See Troughton & Simms Transit Telescope. The mirror still has the original figure. I have a great bonus - a lot of the original paperwork describing the sale to Peridier. This paperwork tells about the condition, what was done to it (and the transit, which were both sold to Peridier) at Broadhurst & Clarkson.
I have not motorized the declination shaft yet, but plan to do so soon. I have a 3" F15 scope in a brass tube which I am using as a guidescope for it. The mount is capable of carrying a lot of extra weight, so anything else I choose to add should be no problem. Another counterweight was added, as the ones in use were at the end of the counterweight shaft. It is easily adjustable with knobs. New parts had to be made to replace missing pieces. Everything works now as it should, and once again this old telescope is capable of doing fine work.