For those old timers who knew Clinton Ford, I have seen this ad on Cloudy Nights today.
I got these recently, but realized they're really not for me and I already have a 4" Mak.
The primary is an uncoated 4.75" Pyrex mirror that has been cored. I tested it and it's a perfect sphere with a 10.5" ROC.
The corrector appears to be crown glass. It's 4.5" in diameter and about 0.3" thick with an ROC of ~6" on the convex side. I could not measure the concave side. There is a 24mm aluminized spot on the convex side of the corrector, but it's pretty damaged and probably needs to be redone.
These optics came with a note on their specifications (which are roughly correct) that on the back says "From the Desk of Clinton B. Ford". For those of you who don't know, Ford was a big variable star observer from the 1930s to the 1980s, and was president of the AAVSO in 1961. I'm guessing that he made these optics, probably sometime in the 1960s.
$125 + PayPal + shipping.
Anyone out there know anything about this glass?? John Bortle, do you?
Clint holds a special place in the history of the AAVSO.
Again, this is an ad I found. I am NOT the person selling this.
Chris Stephan SET