In article 9d510bd6-d2e3-4561-a424-
, RichA says...

This "lens" uses an 8 inch mirror with a steep curve and a front corrector lens to achieve that speed. The film (unit is from the 1970's) is 1 single 35mm frame mounted INSIDE the lens (see door) on a curved magnetic disk. This is because the film plane is curved. However, today a digital camera and field-flattened could be incorporated into it. Would make an interesting project.
The unit uses and internal cage made of Invar rods so there is no focus change with temperature change.

https://www.ebay.com/itm/Celestron-8...%7C10#viTabs_0

It says "Apertu 305 mm". But if the pupil diameter was
305mm, wouldn't this be a 300mm /F1.0 lens?
--
Alfred Molon

Olympus 4/3 and micro 4/3 cameras forum at
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https://myolympus.org/ photo sharing site