Bill, it was designed by telescope maker Joseph Fraunhoffer, for the Dorpat refractor, which my memory is telling me was a 9". 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. William Biesele <bill@biesele.net> wrote:
Etymology question for the group. Why is this kind of mount called a german equatorial mount? I assume the first word is from the country in which it was invented or popularized. The third word is obvious. But why equatorial instead of polar? It's aimed at the pole not the equator.
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Chuck, once again the breadth of knowledge that you seem to have at your "fingertips" (why not tendrils of the mind?) amazes me. Want to trade a few brain cells? I'm not sure what I have to offer, but I'm working on it. ----- Original Message ----- From: "Chuck Hards" <chuckhards@yahoo.com> To: <utah-astronomy@mailman.xmission.com> Sent: Thursday, September 08, 2005 12:20 PM Subject: [Utah-astronomy] German Equatorial | Bill, it was designed by telescope maker Joseph | Fraunhoffer, for the Dorpat refractor, which my memory | is telling me was a 9". | | 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. | | William Biesele <bill@biesele.net> wrote: | | > Etymology question for the group. Why is this kind | > of mount called a | > german equatorial mount? I assume the first word is | > from the country | > in which it was invented or popularized. The third | > word is obvious. | > But why equatorial instead of polar? It's aimed at | > the pole not the | > equator. | | | | | | ______________________________________________________ | Click here to donate to the Hurricane Katrina relief effort. | http://store.yahoo.com/redcross-donate3/ | | _______________________________________________ | Utah-Astronomy mailing list | Utah-Astronomy@mailman.xmission.com | http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy | Visit the Photo Gallery: http://www.utahastronomy.com | | ______________________________________________________________________ | This e-mail has been scanned by Cut.Net Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on Cut.Nets Content Service, visit http://www.cut.net | ______________________________________________________________________ | |
Chuck: That makes sense, thanks. Bill B. On Sep 8, 2005, at 12:20 PM, Chuck Hards wrote:
Bill, it was designed by telescope maker Joseph Fraunhoffer, for the Dorpat refractor, which my memory is telling me was a 9".
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.
William Biesele <bill@biesele.net> wrote:
Etymology question for the group. Why is this kind of mount called a german equatorial mount? I assume the first word is from the country in which it was invented or popularized. The third word is obvious. But why equatorial instead of polar? It's aimed at the pole not the equator.
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--- 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
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participants (6)
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Canopus56 -
Chuck Hards -
diveboss＠xmission.com -
Kim Hyatt -
Steven L. Dodds -
William Biesele