Crossley telescope
Encyclopedia
The Crossley telescope is an 36 inches (914.4 mm) reflecting telescope
located at Lick Observatory
in the U.S. state
of California
.
politician Edward Crossley
, it was rebuilt from the ground up as it was on a very flimsy mounting. It is still being used today in the search for extra-solar planets. The mirror, and some of the initial mounts came from the 36 inch reflector originally mounted in Andrew Ainslie Common
's back yard Ealing
obsevatory, who had used it from 1879 to 1886 to prove the concept of long exposure astrophotography
(recording object too faint to be seen by the naked eye for the first time). Common sold it to Crossley who had it until 1895.
Observations by James Keeler helped establish large reflecting telescopes with metal coated-glass mirrors as astronomically useful, as opposed to earlier cast speculum metal
mirrors. Great refractors were still in vogue, but the Crossley reflector foreshadowed the success of large reflectors in the 1900s. Other large reflectors followed such as the Harvard 60-inch Reflector, also with a mirror by A.A. Common and the Hamburg Observatory Hamburg Spiegelteleskop 1 meter (39.4 in) reflector.
Nicholas Mayall
was a long time user of the Crossley and added a slitless spectrograph to extend its usefulness in the face of larger telescopes.
Reflecting telescope
A reflecting telescope is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the refracting telescope which, at that time, was a design that suffered from...
located at Lick Observatory
Lick Observatory
The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA...
in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
History
Given to the observatory in 1895 by BritishUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
politician Edward Crossley
Edward Crossley
Edward Crossley was an English businessman, Liberal Party politician and astronomer.-Biography:Edward Crossley was the eldest son of Joseph Crossley J.P., of Broomfield, Halifax, Yorkshire, of the Crossley carpets dynasty. He inherited his family's carpet manufacturing business from his father...
, it was rebuilt from the ground up as it was on a very flimsy mounting. It is still being used today in the search for extra-solar planets. The mirror, and some of the initial mounts came from the 36 inch reflector originally mounted in Andrew Ainslie Common
Andrew Ainslie Common
Andrew Ainslie Common FRS was an English amateur astronomer best known for his pioneering work in astrophotography.-Biography:...
's back yard Ealing
Ealing
Ealing is a suburban area of west London, England and the administrative centre of the London Borough of Ealing. It is located west of Charing Cross and around from the City of London. It is one of the major metropolitan centres identified in the London Plan. It was historically a rural village...
obsevatory, who had used it from 1879 to 1886 to prove the concept of long exposure astrophotography
Astrophotography
Astrophotography is a specialized type of photography that entails recording images of astronomical objects and large areas of the night sky. The first photographs of an astronomical object were taken in the 1840s, but it was not until the late 19th century that advances in technology allowed for...
(recording object too faint to be seen by the naked eye for the first time). Common sold it to Crossley who had it until 1895.
Observations by James Keeler helped establish large reflecting telescopes with metal coated-glass mirrors as astronomically useful, as opposed to earlier cast speculum metal
Speculum metal
Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors...
mirrors. Great refractors were still in vogue, but the Crossley reflector foreshadowed the success of large reflectors in the 1900s. Other large reflectors followed such as the Harvard 60-inch Reflector, also with a mirror by A.A. Common and the Hamburg Observatory Hamburg Spiegelteleskop 1 meter (39.4 in) reflector.
Nicholas Mayall
Nicholas Mayall
Nicholas Ulrich Mayall was an American observational astronomer. After obtaining his doctorate from the University of California, Berkeley, Mayall worked at the Lick Observatory, where he remained from 1934–1960, except for a brief period at MIT's Radiation Laboratory during World War II.During...
was a long time user of the Crossley and added a slitless spectrograph to extend its usefulness in the face of larger telescopes.
See also
- List of largest optical telescopes in the 20th century
- List of largest optical reflecting telescopes