Click to go to Sirius Observatory Main Page

Peridier Double Refractor



Julian Peridier had an observatory in Le Houga, France. In one dome he had a 12.3" Calver, and in the other dome he had this magnificent telescope. It is on a T. Cooke equatorial mount. The mount was modified by Manent, and he had two lenses made by Couder. One was a photographic lens (now lost), and the other was a visual lens. These were mounted in twin side-by-side tubes.

Manent also made a filar micrometer for Julian Peridier. The refractor was brought over but never assembled in this country, thus the older photo below was taken in France in the 60's or before.

This restoration project has involved many decisions, many parts, and I was extremely lucky to get photos of the scope while in France to assist with the restoration. Those of you familiar with restoring things know there are many kinds of restorations - back to original, like it was in a certain time period, to look like original but work with modern accessories, and to be put in a museum but not used. I am restoring it to look like it did, but with modern drives.

The 12.3" Calver was modified to go to Africa for the solar eclipse in 1973, which was in Chinguetti in the Saharan desert republic of Mauritania. They installed a new Byers worm drive, along with other modifications. I was going to use this worm drive system on the double tube scope, and put the original back on the Calver. Then I managed to obtain a brand-new in the box 22.5" Byers. I measured first to make sure it would fit. The twin tube scope uses a tangent arm drive for the declination axis, which I planned on not using. I was thinking of a goto drive system. But I mostly observe the sun and planets, so I decided a goto system was not needed. So I decided to use the tangent arm after all, which meant the 22.5" Byers was about 2" too big. Right now I am looking for a smaller drive system. There were a few missing pieces, and I was able to make most of them myself with the lathe and milling machine. I did get help with the pieces that required Metric threads, which my lathe does not cut.

Scroll down for more pictures.

The double 8" refractor as it was in France in the 60's.

R.A. shaft. you can see the ~1" shaft on the right.

DEC shaft

Cooke mount shown partially assembled showing also the tangent arm. The lower portion of the mount is in the background, as it would be too tall to work on if put together.

I had the lock part, but it did not fit on the shaft. The missing piece is one of the pieces I made.

Finished piece.

New piece from the side. 

The original setup was a visual lens in the top tube, and a photographic lens and large camera on the second tube. My plan is to have another lens made, and use the focuser on the bottom. By making the brass plates, I can use the second focuser with the new lens, without changing or adding holes or anything on the original tube.

Together for the first time since the 60's. Well not totally, the bottom 4 feet of the pier is still in the observatory.