Download Orrery

About Orrery

"Orrery" is an orbital-motion visualisation application. Orrery shows the sun and planets, minor planets, our moon, stars and earth satellites. It uses an intuitive graphical interface to display orbital motion, for both planetary astronomy and satellite dynamics. It is designed from the ground up as a tool for educators in astronomy, but may also be used to determine visibility, look angles, and ground tracks. Orrery allows both plane projections and perspective views, with either user-selected view angles or automatic tracking.

An "orrery" is a mechanical apparatus showing the relative positions and motions of members of the solar system. It is named after the fourth Earl of Orrery, Charles Boyle (1676-1731), for whom an early model was made.

Orrery works on any Macintosh with system 7 or later. It uses about 1.5 Mb of disk space, and needs about 3 Mb of RAM to run comfortably. With a large monitor or with several windows open, 4 Mb is better.

Freeware

Orrery is freeware. It used to be shareware, but isn't now. I also can't offer any support for it. (The fee was for use of the application programme, not for the text resources or orbital element sets. These resources are drawn from a variety of public sources on the Internet and in print.)