This group began due to a discussion between members of Cloudynights.com on practical, medium-aperture astrographic optical systems based on Seymour Rosin's original design concept. What started as some design thoughts has morphed into real Rosin projects by some members to build 8" and 10" Rosin astrographs per designs by Mike Jones. This group is also open to the discussion of other astrographic optical designs as well, including such systems as Cassegrains with field correctors, etc.

This is a moderated group. Spamming of any type will NOT be tolerated, and will be removed as soon as possible.

Special thanks to Ed Jones for making the Rosin corrector lens sets! Ed made six sets of them, and the new picture at right shows one such set, delivered to Mike. The S-FPL52 element is on the left, and the K5 element is on the right.

Thanks to all the folks from CloudyNights for starting this group and keeping it going!