Thread: Making a 20" Gregorian.
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  #116  
Old 28-04-2019, 12:18 PM
Billyboy78 (Bill)
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Billyboy78 is offline 		 
Join Date: May 2018
Location: CRESTMEAD Brisbane
Posts: 103
I don't have much faith in Ronchigrams. When I was measuring the 20" the ronchi looked clean as a whistle but the ke showed a distinct raised centre.

Polishing is done on the secondary, now to figure an ellipse.
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