Gravit is a gravity simulator which runs under Linux, Windows and Mac OS X. It uses Newtonian physics. Although the main goal of Gravit is to be as accurate as possible, it also creates beautiful looking gravity patterns.
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Complete 2014 Nautical Almanac in pdf format complete with monthly star charts. Includes Parallax corrections for the planets which are not normally available.
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Aciqra is a free and open source virtual planetarium and sky mapping program which tracks celestial bodies including planets, deep sky objects and stars.
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Twelve months in the making and Solar Kingdom has now been released.
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Accurate, flexible wireframe simulator for the Voyager and Giotto space missions, with animation capability. Developed at JPL for science/navigation, and filmed by the BBC/NOVA. Conveniently runs from any Windows/DOS.
Downloads: 41416 - Freeware - Download Now