A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tracy Shrier
Date: 2021 Feb 12, 11:52 -0800
Attached are pictures of my CPU-300/U, manufactured by Allegheny Plastics, and my CPU-50A/P, manufactured by Felsenthal Instruments.
I would suggest that Michalis Vaidanis' instrument is a -50A/P that had the astrotracker field of view overlay (green disk) never attached or removed to market/release as a -300/U. Maybe the astrotracker function was classified or restricted at the time.