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Alvan Clark Refractors and the Double Vision Micrometer

There are 2 Clark refractors in the observatory, a 4" and a 6" - both F15, both brass tubes.


Original crate, terrestrial eyepiece, set of eyepieces, sun and star diagonals, and hard to find number 5 mount.

Known history of the scope is as follows:
Serial number: # 470
Date of manufacture is 1911
Originally sold to Charles E. Smith from Chicago, IL. 1911 (If you know anything about him let me know.)
Then an unknown period of history:
It next showed up at antique shop, where Joel Corwin purchased it;
I bought it from him in 1995.


Original crate, terrestrial eyepiece, set of eyepieces, sun and star diagonals, John Byrne mount.

Serial number: unknown at this time as it is not on the lens.
Date of manufacture is late in 1932. The instrument dealer Rasmussin, from Amsterdam, New York, sold it to George Slack at the Kitchi Gammi Club in Duluth, Minn. in February 1942. He apparently knew the history of the instrument, as he knew when it was made and what came with it when it was originally sold.

Then a period of unknown history until it was owned by Dr. Robert Hardie, from Vanderbilt University. I found out that Dr. Hardie graduated from Chicago, then worked at Yerkes for a while.  Dr. Hardie purchased the Clark from George Slack in 1958. Dr. Giessow bought it from Dr. Hardie in 1964.
I bought it from Mrs. Giessow in September, 1991. I have a lot of paperwork from the dealer and other people involved.

4" and 6" F15 Clark refractors  on tripods


Clark eyepieces, solar and star diagonals, and terrestrial eyepiece 


Both Clarks set up on Astro-Physics 1200 mount. I made the dewshields. 



Detail of mounting. I made the  dovetails and adjuster so the two scopes can be aimed at the same place.


The rare #5 mount under the 4" Clark. 


Set up for solar viewing at Springfield, MO Discovery Center. 


4" Clark in original crate 


6" Clark on original tripod 


6" Clark on original pier 


John Byrne mount under the 6" Clark 


Silver setting circles on the Byrne mount.