The Criterion DYNASCOPE Group
Non-profit affiliation of enthusiasts devoted to restoring and recommissioning classic Newtonian telescopes.
http://home.wmis.net/~rv6/

Galaxies Astronomy Club
An online community for beginning and veteran astronomy enthusiasts alike to learn more about telescopes, cosmology and astronomy. Delphi membership required.
http://forums.delphiforums.com/astro

Heavens Above astronomy forum
Forum for those interested in astronomy especially satellites.
http://groups.yahoo.com/group/heavens-above/

NexStar 50 Club
An observing club for NexStar telescope owners - granting certificates and admission for those viewing 40 of the 50 objects on the Club's NexStar 50 List.
http://www.angelfire.com/ns/nexstar/nexstar50club.htm

The Dynascope Group
Enthusiasts dedicated to remembering, restoring and recommissioning classic Criterion telescopes.
http://www.dynascope.com

Association of Christian Astronomers International
An Internet-based hub for Christian astronomers, both professional and amateur. Offers free membership.
http://www.christian-astronomers.org/