I think history is important in astronomy. Partly because the terminology raises questions about history (like: Why are some black holes called quasars? Why the sequence OBAFGKM?) Partly because astronomy is developing quickly and is making history today, maybe on a more fundamental level than any other science. The recent remake of the TV series Cosmos had a strong emphasis on the history of astronomy.
Practically, I think that questions about the history of astronomy can get much more and better answers here than in any community about history in general. I think that the tag "history" will work here until there's enough interest to create a History of Astronomy community.