Boresite for Fastair camera

This is a boresite for focusing fastair cameras.  It is a standin for the camera wherever the camera may be positioned and need to be focuses.

The front bit of the black optical tube has a lens with a crosshair etched in the flat surface there.  The opposite end is an eyepiece thru which you can focus and view the eyepiece.  There is a two piece draw tube focuser which is secured by the two set thumb screws on the right side.

It is all in a a nice Wollensak wood case for storage.

Fastair lenses. Elgeet and Wollensak.

2 inch, 35mm, 2 x 13mm (1/2 inch)

in 16mm format 1inch, 25mm is "normal" lens.  This 50mm is F2, which is pretty fast for 16mm telephoto.

both 13mm lenses are very fast, f1.5