Comet seekerA comet seeker is a type of small telescope adapted especially to searching for comets: commonly of short focal length and large aperture, in order to secure the greatest brilliancy of light.[1] This style of telescope was used to discover the asteroid 9 Metis in 1848. DesignA comet seeker telescope is a type of optical device that is known for having a short focal length but a wide field of view.[2] ExamplesA comet seeker with about 3.9 inch aperture was installed at the United States Naval Observatory in 1843, and later transferred to the Smithsonian Museum in 1866.[2] It had an aperture of 4 inches (10.2 cm) and was made by Utzschneider & Fraunhofer in Munich.[3] 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.[3] Markree Observatory added a 3-inch aperture Comet Seeker on an equatorial mount by Ertel.[4] It was ordered in 1842, and in place until 1874.[4] The Markree Comet Seeker was used to discover 9 Metis in April 1848.[5] It was discovered by Edward Cooper's assistant Andrew Graham, who worked at that observatory until 1860.[4][5] Graham also observed and sketched the Orion nebula with this Ertel Comet seeker.[5] An 8.6-centimetre (3.4 in) aperture Comet Seeker was used, with some customizations, to produce the Bonner Durchmusterung star catalog from Bonn Observatory, in the 19th century.[6] In 1866 a Comet Seeker telescope of 18 centimetres (7.1 in) aperture by Martin was acquired by the Marseille Observatory in France.[7] See alsoReferences
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