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A comet seeker is a type of small
Photograph of comet seeker telescope used in the Lick Observatory circa 1893 from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections
Telescopes {{astronomy-stub
A comet seeker is a type of small telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to obse ...
adapted especially to searching for comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...
s: commonly of short focal length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foc ...
and large aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An ...
, in order to secure the greatest brilliancy of light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...
. This style of telescope was used to discover the asteroid 9 Metis
Metis (minor planet designation: 9 Metis) is one of the larger main-belt asteroids. It is composed of silicates and metallic nickel-iron, and may be the core remnant of a large asteroid that was destroyed by an ancient collision. Metis is esti ...
in 1848.
;Design
A comet seeker telescope is a type of optical device that is known for having a short focal length but a wide field of view.
;Examples
A comet seeker with about 3.9 inch aperture was installed at the United States Naval Observatory
United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. Established in 1830 as the Depo ...
in 1843, and later transferred to the Smithsonian Museum in 1866. It had an aperture of 4 inches (10.2 cm) and was made by Utzschneider & Fraunhofer in Munich. This was operated as part of suite of several other instruments including a larger refractor on an equatorial mounting, a meridian transit, mural circle, etc.
Markree Observatory
Markree Observatory was an astronomical observatory in County Sligo, Ireland. The asteroid 9 Metis was discovered from this observatory in 1848 by Cooper's assistant Andrew Graham using a comet seeker telescope. (Signed 29 April 1848; the discove ...
added a 3-inch aperture Comet Seeker on an equatorial mount by Ertel. It was ordered in 1842, and in place until 1874.
The Markree Comet Seeker was used to discover 9 Metis
Metis (minor planet designation: 9 Metis) is one of the larger main-belt asteroids. It is composed of silicates and metallic nickel-iron, and may be the core remnant of a large asteroid that was destroyed by an ancient collision. Metis is esti ...
in April 1848. It was discovered by Edward Cooper's assistant Andrew Graham, who worked at that observatory until 1860. Graham also observed and sketched the Orion nebula
The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion. It is one of the brightest nebulae and is visible to the naked eye in the ni ...
with this Ertel Comet seeker.
An aperture Comet Seeker was used, with some customizations, to produce the Bonner Durchmusterung
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, compiled by the Bonn Observatory in Germany from 1859 to 1903. The name comes from ('run-through examination'), a German word used for ...
star catalog from Bonn Observatory
The federal city of Bonn ( lat, Bonna) is a city on the banks of the Rhine in the German state of North Rhine-Westphalia, with a population of over 300,000. About south-southeast of Cologne, Bonn is in the southernmost part of the Rhine-Ruhr ...
, in the 19th century.
In 1866 a Comet Seeker telescope of aperture by Martin was acquired by the Marseille Observatory in France.
See also
*List of telescope types
The following are lists of devices categorized as types of telescopes or devices associated with telescopes. They are broken into major classifications with many variations due to professional, amateur, and commercial sub-types. Telescopes can be ...
* List of largest optical telescopes in the 19th century
* Lists of comets
References
External links
Photograph of comet seeker telescope used in the Lick Observatory circa 1893 from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections
Telescopes {{astronomy-stub