This finder scope has a helical focuser, a miniature version of the helical focuser of the 80mm F15. Rotating the focus collar, the eyepiece tube extends from the focuser body. The eyepiece tube ends in what appears to be a 30mm internal thread, into which threads a machined aluminum 0.965" eyepiece holder, complete with setscrew.
The mystery I am inquiring about is the origin of the 30mm thread. Is it "standard anything"?
Edited by rmorein, 20 February 2025 - 08:49 PM.