--- Chuck Hards <chuckhards@yahoo.com> wrote: <snip>
Only one axis is aimed at the pole, the instrument mounted on it can be aimed anywhere. Objects being tracked by such a mount describe motion parallel to the celestial equator. . . . . Why is the English Yoke not called even equatorial? The nomenclature of mounts has no logic.
The equatorial mount takes its name from the fact that while the first drive-powered axis is parallel to the Earth's axis, the second is parallel to Earth's equator. The German Equatorial Mount (GEM) takes is name from the historical development that you note. English Yoke mount is also known as the equatorial mount - for the same characteristic that its secondary axis is parallel to the Earth's equator. http://www.astro.ufl.edu/~oliver/ast3722/lectures/BasicScopes/BasicScopes.ht... Can't remember who invented the yoke mount. Herschel? - Canopus56 (Kurt) P.S. - Here's some pictures of some familar modified asymetric GEMs: http://slas.us/spoc/spocpix/SPOC048.JPG http://slas.us/images/SPOC2/SIEGFRIEDJ001.jpg __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com