под линух вот нашел http://howto.astronomy.net/howto/http://www.randomfactory.com/lfa.htmlhttp://dmoz.org/Science/Astronomy/Software/http://www.linux.org/apps/all/Scientific/Astronomy.htmlпод винду http://astro.nineplanets.org/astrosoftware.htmlhttp://www.download-free.programas-gratis.net/php/subcategories.php?id_subcategoria=96&software-Astronomyhttp://www.windows.ucar.edu/tour/link=/the_universe/uts/timeline.htmlhttp://www.stella2000.com/http://www.fourmilab.ch/homeplanet/В общем гугль рулит!