20-Inch-Telescope-Mirror

Perkin Elmer/Boller & Chivens 20" F8 primary telescope mirror

Per John Urciolo

Regarding the mirror... It came from a former NASA facility that excessed it along with the Unertyl mount. There are no specific numbers on any part of the mirror or its heavy circular housing. I was able to determine that it was made by Perkin Elmer/Boller & Chivens from the original government sheets. No additional information such as a model or serial number was provided by NASA. The Unertyl mount is intended to allow X-Y positioning of the mirror while holding it securely on an optical bench (for optical calibration??). I am assuming this mirror to be parabolic due to the fact it was intended to the best of my knowledge to ultimately be used in a telescope.

My Deductions

The central hole appears to be about 4 inches in diameter. Boller and Chivens was a telescope company that was bought by Perkin Elmer is my conclusion and they made optical telescopes and some spectrographic instruments. The mirror figure is either suitable for a human viewing telescope or a schmidt camera. The curvature implies human use.

Notes

• Andrew mentioned he can do overcoatings
• www.clausing.com Clausing is very expensive. I have an email in to get a quote on a 20" mirror recoat
  
  
• John came back with a figure of 0.25 inches for the sagitta of this mirror
• Online Sagitta Calculator
  
  

Inputs Value

• Sagitta ==== 0.25 inches
• Diameter ==== 20 inches

Mirror Parameters

• ROC ==== 200 inches
• Focal Length (F) = R / 2 ==== 100 inches
• Focal Ratio (f) = F / D ==== 5X