Groombridge Transit Circle
Groombridge transit circle
Groombridge Transit Circle was a meridian transit circle made by Edward Troughton for Stephen Groombridge in 1806, which Groombridge used to compile data for the star catalogue, Catalogue of Circumpolar Stars.[1] The advantage of a transit circle over a mural circle (which can measure polar distances) is that it allows measuring right ascension and declination at the same time. [2]
It had an aperture of 3.5 inches and a 5 foot focal length, mounted inside two 4 foot circles on stone piers. [2] Groombridge used the instrument to determine the positions of over 4000 circumpolar stars.[2]
It was eventually bought by James South, and it remained at his observatory at Kensington until 1870.[2]
References
- ↑ Groombridge Transit Circle, 1820. -- Science and Society Picture Library
- 1 2 3 4 King, Henry C., (1955/2003). The History of the Telescope. Cambridge, Massachusetts: Sky Publishing Corporation. Retrieved from Google Books in 2010: The History of the Telescope, by Henry C. King, page 234-6
See also
External links
This article is issued from Wikipedia - version of the Saturday, August 21, 2010. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.