For general information on a variety of astronomical topics visit the home pages of the societies listed below:
Federation of Astronomical Societies -As the name suggests, FAS is the UK national federation of local astronomical
societies. If you want to find your local society (and if its not listed here),
this is a good place to look.
The British Astronomical Association - The BAA is the UK national amateur astronomical organisation. They hold national
events and organise observing programmes amongst many other things.
The Royal Astronomical Society - The UK's leading professional body for astronomy & astrophysics, geophysics, solar and solar-terrestrial physics, and planetary sciences.