Manufacturer = Perkin Elmer  /  Boller and Chivens    

Last Owner = NASA

Diameter=20 inches

Central Hole Diameter = 5 inches

Sagitta=0.400 inch

Thickness= 3.5 inches

F Ratio calculates out to be 3.1     Check my math on this using: Fratio Calculator

Weight=~ estimated to be 80 lbs.  ( measured one side while other side is supported....this should yield approximately 1/2 the weight.  This number was doubled to calculate the weight.

Coating Condition = Acceptable and quite usuable as is.   There are a few minor blemishes

Flaws:  Has 2 minor chips on the bottom  ( that is the far side of the working optical side for those who I know will email me asking !! ) Photos included.

 Boller and Chivens appears to be an optical outfit that Perkin Elmer bought out.  When you google them it appears they made professional grade optics for full up laboratory grade observatories.

If you know more about but not limited to:

   1- the Boller and Chiven company

   2- can deduce approximate optics train design

   3- what NASA used this mirror for

I would like to hear from you.