How old is it
Posted 06 February 2013 - 08:12 PM
Posted 06 February 2013 - 08:13 PM
Posted 06 February 2013 - 09:44 PM
Posted 06 February 2013 - 10:01 PM
Posted 07 February 2013 - 07:25 AM
Posted 07 February 2013 - 07:45 AM
Posted 07 February 2013 - 08:09 AM
The reason for the mirror cell design using pins to hold the primary was to not introduce diffraction from the mirror clips. Because the system is using a small diamater secondary and most likely between F/15 and F/20 someone was try to make a high res planetary scope but without the baffles the image contrast will be poor.
Posted 07 February 2013 - 08:33 AM
Posted 07 February 2013 - 08:42 AM
Posted 07 February 2013 - 10:13 AM
The primary looks to be made from a Corning Pyrex "slope sided" blank that were common from the '50's into the mid 1970's. Both Coulter and 3B used them, depending on when the optics were made and they were also what was sold in mirror making kits by Edmund and Jaegers. They were most common in the 1960's.
A number of ATM constructed Cassegrains were built following Novak's book on the subject "Cassegrain Notes" http://bobmay.astron...Notes/index.htm using commerical optics and Novak parts.