In July 2025, Tom Dugan posted some 1975 photos of a Unitron Model 620 that was located on the Davey Lab at Penn State University. Tom indicated that there might have also been a second Unitron Model 620 located at the off campus solar observatory.
Based on Tom’s input, I contacted the Physics Department of PSU and they put me in contact with Professor Chris Palma, the resident historian on telescopes and observatories at the university. He assured me that there was at least one 6 inch Unitron, and forwarded photos of the 4 inch Unitron guide scope, and the Model 100 Astrograph. Both are in mint condition.
Additional information and photos will be added as they become available.