These are the original Stellarvue Nighthawk lenses made nearly a quarter of a century ago and kicking around here in storage ever since. These are 80 mm f-6 achromatic objectives using BK7/F2 optical glass, fully-multi-coated and mounted in an aluminum cell that was made for a tube with an M90X1 thread and a threaded dew shield. You will have to supply those parts. Alternately, one could mount the lens by drilling three holes in the cell where the female thread is and slipping it over the proper diameter tube and screwing it to the tube.
These lenses were made long before we did any interferometric testing. We consider these to be commercial quality grade a or grade b. They will make a wonderful richest field telescope or super finderscope. When we moved from achromats to ED and then SD lenses, we stopped selling these once we ran out of tubes and focusers. We have been storing these ever since and we now need the room. Make yourself your own 80 mm f-6 achromatic telescope. The hardest part is done.
