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Secretan, Marc Francois Louis

Nationality:  Swiss

Brief Bio:  1804-1867, mathematician; scientific instrument maker, Swiss

until 1844 - professor of mathematics at Academy of Lausanne;
1840 - worked with Friedrich von Martens and Samuel Heer producing daguerreotypes;
1844 - moved to Paris;
1845 - partnership with Lerebours as Lerebours & Secretan; used joint name until 1880s and beyond.
1855 - after retirement of Noel Paymal Lerebours became sole proprietor of Lerebours and Secretan, and signed

It's hard to predict how an antique telescope will perform.

The Manent is fantastic. Made in the 1920 - 1930 by the French telescope maker Mauric Manent. It's a pleasure to observe with. Even the lenses are uncoated it still gives a very good contrast and color. Sharp and beautifull color. Even at 250x the images were crisp and the color with no aberrations. The focuser is very nice.That's the kind of telescopes I like very much.

New find. 90mm f1170mm refractor on altaz fork mount.
The lens is extremely good. Sharp and good contrast. The lens has no coating. Must be made between 1900 and 1914. No indication of a brand.
Original wooden box for the telescope and mount.

The eyepiece has a strange diameter: 22mm. No standard diameter

The central colon of the mount be raised.
The mount and tripod are very stable.
The telescope, mount and tripod have been repainted by a former user.

In my research for more background information about the Gajdusek-Kozelsky telescopes from the Zdanice Observatory I found an article in the Slovak astronomy magazine about a similar 20cm refractor build by Kozelsky.

7 June 2015

Last first light for the Gajdsuek_Koselsky 16cm refractor on the Alt Azimuth mount.
I don't know when it was the last time scope saw star light?

Two photos of how I found the scope laying in one of the domes.

The other photo is the scope standing in the garden ready for observation.

Refractorphil and his son joined for the first light.

It was a little puzzling to find the right pieces to fit the eyepieces. When you use an Altaz mount it's difficult to use high power eyepieces. Betwe

A family shot of the different focuser of the scopes.

On the left the Cassegrain Focuser, middle the 16cm refractor focuser and right the 20 cm focuser.

The eyepiece attachment system is very similar to the Zeiss system.
This are the 3 different eyepiece dovetails from the different focuser's. It are Zeiss style dovetails. Or are it original Zeiss dovetails?
More and more I find indications that Kozelsky knew very well the Zeiss Jena material.
The large Zeiss Jena scopes were "common" in Eastern