Fast 84mm Doublet (2 of 2)

Auction No.:
Current Bid:
High Bidder:
Mark Baribault
Bid History:
7 Bids
Scotia, NY - US
Alan French
11/07/2019 07:42PM
11/17/2019 07:42PM
Buyer pays shipping
PayPal, Personal or Cashier's Check, Money Orders
This is the second of two. It is an ~84mm diameter doublet, 14mm thick at the edge, with a focal length of 9-inches (~228mm), so about f/3 at an aperture of 76mm. 

Certainly not intended at a telescope objective - too fast for a good achromat at the aperture and not kind to eyepieces at f/3. But it might be fun to play with, perhaps as a finder objective, or maybe some ATM has some other use for a fast doublet. I was tempted to hold onto one of them just because it's interesting. 

It is coated on the front, probably MgF. The back is uncoated. The workmanship is excellent, the surfaces are free of scratches, and the edging and cementing looks fine. There are a few small chips around the front edge and I've tried to properly photograph them all. 

Let me know if you have questions. 

Clear skies, Alan