An equatorial sextant is a modified version of a sextant. One historically significant instrument called by that name was John Flamsteed's equatorial sextant, installed in the Greenwich Observatory in 1676. Seven feet across and possessing an iron frame,[1] it was mounted at an angle that aligned with the celestial equator, so that as it rotated, it tracked the motion of objects across the night sky.[2] Flamsteed used this instrument to measure angles of right ascension from 1676 through 1689[3] or 1690.[4]
Another device known by that name was patented by the American inventor William Austin Burt in 1856.[5] Burt's equatorial sextant included several elaborations on the basic sextant design, which enabled its user to determine navigational information without a supplemental chart or the need for calculation.[6]
References
- ^ Laurie, P. S. (1960). "The buildings and old instruments of the Royal Observatory, Greenwich". The Observatory. 80: 12–22. Bibcode:1960Obs....80...13L.
- ^ Chapman, Allan (September 1984). "Tycho Brahe in China: the Jesuit mission to Peking and the iconography of European instrument-making processes". Annals of Science. 41 (5): 417–443. doi:10.1080/00033798400200341. ISSN 0003-3790.
- ^ "Telescope: Flamsteed's 7-foot Equatorial Sextant (1676)". www.royalobservatorygreenwich.org. Retrieved 2023-03-01.
- ^ Chapman, Allan (September 1995). "Out of the meridian: John Bird's equatorial sector and the new technology of astronomical measurement". Annals of Science. 52 (5): 431–463. doi:10.1080/00033799500200341. ISSN 0003-3790.
- ^ "Equatorial Sextant". National Museum of American History. Retrieved 2023-02-28.
- ^ Briley-Webb, Linda (2019-02-22). "Equatorial sextant". In Welch, Rosanne; Lamphier, Peg A. (eds.). Technical Innovation in American History: An Encyclopedia of Science and Technology [3 volumes]. ABC-CLIO. pp. 225–226. ISBN 978-1-61069-094-2.