Product Description
This item appears to be the business end of a collimator telescope. The outer barrel is 2.75 inches in diameter and there are centering screws in two locations on the barrel, one set for the objective cell, and the other set for an internal mounting ring which is currently empty. The objective clear aperture is 48mm. The objective is coated and is in excellent condition with the exception of a small scratch near the margin (see second photo).
The opposite end of the tube is threaded to receive a multiple-thread helical focusing mount with a 1.94 inch internal diameter (six threads). The focal length of the objective appears to be approximately 175 to 180mm, which would place the focal point at the plane of the empty internal centering ring. Overall length of the tube (without helical adapter) is
207mm.
The only markings on the assembly are a hand-painted part number, GPE-9289.
Photoo set 1524