Weather forecast

Clear Outside - excellent weather forecast for astronomers courtesy of First Light Optics.

Discussion groups

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.

Astronomy groups

List of UK groups

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.

Aurora alerts

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)

Astro equipment suppliers

Green Witch (Birstall)

Stockport Binocular & Telecope Centre Limited
Opticstar Limited (Sale)
Rother Valley Optics Limited (Rotherham)

First Light Optics

Harrison Telescopes

Telescope House
The Widescreen Centre