A reader sent me these pictures with the following message: I've acquired what looks like a sighting scope or range finder that is marked "for collimating telescope MK-60". It has a serial # or part # 686 3 G stamped into the scope base. It is in very good condition. I was wondering if you could supply any information as to its use. I'm interested in selling this piece and was going to list it on ebay. I was wondering if you,or someone you know, would be interested in it before I put it out to the masses.