I have a pair of 3-3/8" achromats of 9" focal length. Mounted, they'd probably be 3" f/3 lenses.
They were acquired long ago with some other optics, and I have no clue as to either their origin or original purpose. Anyone have any thoughts what they'd be useful for? They seem a bit short even for big binoculars.
Also, any thought of what they could be used for. A 25mm eyepiece would yield about 9x, a 5 degree field (if 50 AFVOV), but an overly large exit pupil. I'm guessing an f/3 achromat is not going to do well with a wide field eyepiece.
They are interesting. The edge thickness of the flint is the majority of the thickness of the pair, and that of the crown is very small.
Clear skies, Alan
They were acquired long ago with some other optics, and I have no clue as to either their origin or original purpose. Anyone have any thoughts what they'd be useful for? They seem a bit short even for big binoculars.
Also, any thought of what they could be used for. A 25mm eyepiece would yield about 9x, a 5 degree field (if 50 AFVOV), but an overly large exit pupil. I'm guessing an f/3 achromat is not going to do well with a wide field eyepiece.
They are interesting. The edge thickness of the flint is the majority of the thickness of the pair, and that of the crown is very small.
Clear skies, Alan
