James Edward Keeler
|James Edward Keeler|
James Edward Keeler
September 10, 1857|
La Salle, Illinois
August 12, 1900 42) (aged|
San Francisco, California
Rings of Saturn
|Notable awards||Henry Draper Medal (1899)|
James Edward Keeler (September 10, 1857 – August 12, 1900) was an American astronomer.
Career and personal life
Keeler worked at Lick Observatory beginning in 1888, but left after being appointed director of the University of Pittsburgh's Allegheny Observatory in 1891. He returned to Lick Observatory as its director in 1898, but died not long after in 1900. His ashes were interred in a crypt at the base of the 31-inch Keeler Memorial telescope at the Allegheny Observatory.
Keeler was the first to observe the gap in Saturn's rings now known as the Encke Gap, using the 36-inch refractor at Lick Observatory on 7 January 1888. After this feature had been named for Johann Encke, who had observed a much broader variation in the brightness of the A Ring, Keeler's contributions were brought to light. The second major gap in the A Ring, discovered by Voyager, was named the Keeler Gap in his honor.
|452 Hamiltonia||December 6, 1899|
|(20958) A900 MA||June 29, 1900|
In 1895, his spectroscopic study of the rings of Saturn revealed that different parts of the rings reflect light with different Doppler shifts, due to their different rates of orbit around Saturn. This was the first observational confirmation of the theory of James Clerk Maxwell that the rings are made up of countless small objects, each orbiting Saturn at its own rate. These observations were made with a spectrograph attached to the 13-inch Fitz-Clark refracting telescope at Allegheny Observatory.
His observations with the Lick Crossley telescope helped establish the importance of large optical reflecting telescopes, and expanded astronomers' understanding of nebulae. After his untimely death, his colleagues at Lick Observatory arranged for the publication of his photographs of nebulae and clusters in a special volume of the Lick Observatory publications.
Keeler discovered two minor planets, the Koronis asteroid 452 Hamiltonia in 1899, and the Mars-crosser asteroid (20958) A900 MA in 1900, which became a lost minor planet until its recovery 99 years later.
Honors and Legacy
In 1880, Allegheny Observatory director Samuel Pierpont Langley, accompanied by Keeler and others, went on a scientific expedition to the summit of Mount Whitney. The purpose of the expedition was to study how the Sun's radiation was selectively absorbed by the Earth's atmosphere, comparing the results at high altitude with those found at lower levels. As a result of the expedition, a 14,240-ft. peak near Mount Whitney was named the "Keeler Needle".
- Hockey, Thomas (2009). The Biographical Encyclopedia of Astronomers. Springer Publishing. ISBN 978-0-387-31022-0. Retrieved August 22, 2012.
- Harland, David M. (2002). Mission to Saturn: Cassini and the Huygens Probe. Chichester: Praxis Publishing. ISBN 1-85233-656-0.
- Osterbrock, D. E.; Cruikshank, D. P. (1983). "J. E. Keeler's discovery of a gap in the outer part of the A Ring". Icarus. 53 (2): 165–173. Bibcode:1983Icar...53..165O. doi:10.1016/0019-1035(83)90139-2.
- "Minor Planet Discoverers (by number)". Minor Planet Center. 23 May 2016. Retrieved 21 June 2016.
- "452 Hamiltonia (1899 FD)". Minor Planet Center. Retrieved 21 June 2016.
- "LCDB Data for (452) Hamiltonia". Asteroid Lightcurve Database (LCDB). Retrieved 21 June 2016.
- "20958 (A900 MA)". Minor Planet Center. Retrieved 21 June 2016.
- Keeler, J. E. (1895). "A spectroscopic proof of the meteoric constitution of Saturn's rings". Astrophysical Journal. 1: 416–427. Bibcode:1895ApJ.....1..416K. doi:10.1086/140074.
- Keeler, J. E. (1908). "Photographs of Nebulae and Clusters made with the Crossley reflector". Publications of the Lick Observatory. 8: 1. Bibcode:1908PLicO...8....1K.
- "Proper motion of the Crab pulsar". Royal Astronomical Society, Monthly Notices, vol. 180, Sept. 1977, p. 717-729.
- "Henry Draper Medal". National Academy of Sciences. Retrieved 19 February 2011.
- Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (2261) Keeler. Springer Berlin Heidelberg. p. 184. ISBN 978-3-540-00238-3. Retrieved 21 June 2016.
- Works by James Edward Keeler at Project Gutenberg
- Works by or about James Edward Keeler at Internet Archive
- Campbell, W. W. (November 1900). "James Edward Keeler". ApJ. 12: 239–253. Bibcode:1900ApJ....12..239C. doi:10.1086/140764.
- H. H. T. (February 1901). "List of Fellows and Associates deceased during the past year". Monthly Notices of the Royal Astronomical Society. 61: 197–199. Bibcode:1901MNRAS..61..197.. doi:10.1093/mnras/61.4.197.
- National Academy of Sciences Biographical Memoir