Editing Schmidt camera (section)

==Applications==
[[File:Alfred-Jensch-Teleskop.jpg|thumb|The 2 meter [[diameter]] Alfred Jensch Telescope at the [[Karl Schwarzschild Observatory]] in [[Tautenburg]], [[Thuringia]], [[Germany]] is the largest Schmidt camera in the world.]]

Because of its wide field of view, the Schmidt camera is typically used as a survey instrument, for research programs in which a large amount of sky must be covered. These include [[astronomical survey]]s, [[comet]] and [[asteroid]] searches, and [[nova]] patrols.

In addition, Schmidt cameras and derivative designs are frequently used for tracking artificial Earth [[satellite]]s.

===Ground-based===
The first relatively large Schmidt telescopes were built at [[Hamburg Observatory]] and [[Palomar Observatory]] shortly before [[World War II]].  Between 1945 and 1980, about eight more large (1 meter or larger) Schmidt telescopes were built around the world.<ref>{{cite conference|bibcode=1995ASPC...84....8C|author=Cannon, R. D.  |editor=Jessica Chapman |editor2=Russell Cannon |editor3=Sandra Harrison|editor4=Bambang Hidayat|editor4-link=Bambang Hidayat|title=Schmidt Telescopes: Their Past, Present and Future |conference=Presented at the IAU Colloq. 148: The Future Utilisation of Schmidt Telescopes |location=Bandung; Indonesia |date=7–11 March 1994 |page=8|volume=84|publisher=ASP}}<!--|access-date=1 October 2014 --></ref>

One particularly famous and productive Schmidt camera is the [[Samuel Oschin telescope|Oschin Schmidt Telescope]] at [[Palomar Observatory]], completed in 1948.  This instrument was used in the [[National Geographic Society – Palomar Observatory Sky Survey]] (POSS, 1958), the POSS-II survey, the Palomar-Leiden (asteroid) Surveys, and other projects.

The [[European Southern Observatory]] with a 1-meter Schmidt telescope at [[La Silla Observatory|La Silla]] and the UK [[Science and Engineering Research Council|Science Research Council]] with a 1.2 meter Schmidt telescope at Siding Spring Observatory engaged in a collaborative sky survey to complement the first Palomar Sky Survey, but focusing on the southern hemisphere.  The technical improvements developed during this survey encouraged the development of the [[Palomar Observatory#POSS-II|Second Palomar Observatory Sky Survey]] (POSS II).<ref>{{cite journal|doi=10.1016/0083-6656(77)90001-0|author=Pratt, N. M. |date=1977 |title=The COSMOS measuring machine |journal=Vistas in Astronomy |volume=21 |issue=1 |pages=1–42|bibcode = 1977VA.....21....1P }}<!--|access-date=1 October 2014--></ref>

The telescope used in the [[Lowell Observatory Near-Earth-Object Search]] (LONEOS) is also a Schmidt camera. The Schmidt telescope of the [[Karl Schwarzschild Observatory]] is the largest Schmidt camera of the world.

===Space-based===
A Schmidt telescope was at the heart of the [[Hipparcos]] (1989–1993) satellite from the [[European Space Agency]]. This was used in the Hipparcos Survey which mapped the distances of more than a million stars with unprecedented accuracy: it included 99% of all stars up to [[Apparent magnitude|magnitude]] 11. The spherical mirror used in this telescope was extremely accurate; if scaled up to the size of the [[Atlantic Ocean]], bumps on its surface would be about 10&nbsp;cm high.<ref>{{cite web |url=http://www.esa.int/esaSC/120366_index_0_m.html |title=Hipparcos overview |access-date=2011-03-02 |url-status=live |archive-url=https://web.archive.org/web/20080913205250/http://www.esa.int/esaSC/120366_index_0_m.html |archive-date=2008-09-13 }}</ref>

The [[Kepler photometer]], mounted on NASA's [[Kepler space telescope]] (2009–2018), is the largest Schmidt camera launched into space.

===Other applications===
In 1977 at [[Yerkes Observatory]], a small Schmidt telescope was used to derive an accurate optical position for the planetary nebula NGC 7027 to allow comparison between photographs and radio maps of the object.<ref>{{Cite journal | title=Astrometry with a small Schmidt telescope - The position of NGC 7027| journal=Publications of the Astronomical Society of the Pacific| volume=90| pages=333| doi=10.1086/130337| year=1978| last1=Cudworth| first1=K. M.| last2=Oravecz| first2=M.| bibcode=1978PASP...90..333C| s2cid=122376141| doi-access=free}}</ref>

Starting in the early 1970s, [[Celestron]] marketed an 8-inch Schmidt camera. The camera was focused in the factory and was made of materials with low expansion coefficients so it would never need to be focused in the field. Early models required the photographer to cut and develop individual frames of 35&nbsp;mm film, as the film holder could only hold one frame of film. About 300 Celestron Schmidt cameras were produced.

The Schmidt system was popular, used in reverse, for [[Video projector|television projection]] systems, notably the [[Advent Video Beam Television|Advent]] design by [[Henry Kloss]].<ref>{{citation|title=Three new ways to low-cost, super-bright giant-screen TV|work=[[Popular Science]]|pages=30–33|author=C.P. Gilmore|date=1979|url=https://books.google.com/books?id=iwEAAAAAMBAJ&pg=PA90}}</ref> Large Schmidt projectors were used in theaters, but systems as small as 8 inches were made for home use and other small venues.