Stargazing events, locations and advice at Go Stargazing
Clear Outside - excellent weather forecast for astronomers courtesy of First Light Optics.
Stargazers Lounge - forum to discuss all aspects of astronomy, share pictures and observing reports, and find out what there is to see in the night sky. If you've got a question you are likely to find the answer here. A well-moderated safe site.
Planetarium/sky map/what's in the sky
Stellarium - a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you would see with the naked eye, binoculars or a telescope. Free download.
Universe Sandbox - Space simulator. Play about with orbits, make planets collide and much more. Great fun!
Heavens Above - website to use to find out when the ISS is coming over, sunrise/sunset, moon phases, planet positions, current comets etc.
Aurorawatch UK - sign up for free aurora alerts from Lancaster University.
BGS - another free alert service from the British Geological Survey with a nice graphical representation of current geomagnetic activity.
spaceweather - US-based site with info on aurora, sunspots, flares etc.
Image processing / stacking
GIMP - alternative to Photoshop for image processing - free download.
Deep Sky Stacker - for calibration and stacking of multiple astro images - free download.
StarTools tutorial - an excellent guide to processing a noisy DSLR image using StarTools software by our resident expert Dimitrios Kechagias.
Light pollution (dark sky site finder)
Worldwide Light Pollution Map - zoomable right down to local level in the UK. Useful for finding a dark sky site near you, or the best dark places to visit across the UK and around the world.
Astro equipment suppliers
Green Witch (Birstall)
Opticstar Limited (Sale)
Rother Valley Optics Limited (Rotherham)
Heaton Park Astronomy Group facebook group - chat about the group on facebook
Heaton Park Astronomy Group on twitter - connect to the group on twitter at @HPAstroGroup
Heaton Park Astronomy Group facebook page - Facebook page about the group