I just found this video, the history of the ASTROSCAN.
Norm Sperling talks about the design, development and marketing
of the ASTROSCAN. Interesting to hear about the process and
some the optical details, yes most of the mirror were polished
to parabola, and some coated with extra AL. So there you have it.
Starry Nights
https://www.youtube....h?v=7WXJMSK3F1c