Useful Resources for Astronomers - Software and Articles Online Stellarium Stellarium is a free open source planetarium for your computer. It shows a realistic sky in 3D, just like what you see with the naked eye, binoculars or a telescope. Even better its completely free. Polar Finder Invaluable tool for polar alignment. Shows transit times for Polaris Registax Free stacking / image processing software for astro-photography The Messier Catalogue Complete listing of all 'M' objects showing locations plus photographs. Moon Connection Moon phase program plus facts about our nearest neighbour Metcheck Check the weather for your observing location. .