Location(s) | Palomar Observatory , United States of America |
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Named after | Samuel Oschin |
Coordinates | 33°21′29″N 116°51′43″W / 33.358194°N 116.861806°WCoordinates: 33°21′29″N 116°51′43″W / 33.358194°N 116.861806°W |
Telescope style | Schmidt camera |
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The Samuel Oschin telescope (also named Oschin Schmidt) is a 48-inch-aperture (1.22 m) Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch (f/2.5) mirror. The instrument is strictly a camera; there is no provision for an eyepiece to look through it. It originally used 10- and 14-inch glass photographic plates. Since the focal plane is curved, these plates had to be preformed in a special jig before being loaded into the camera.
Construction on the Schmidt telescope began in 1939 and it was completed in 1948. It was named the Samuel Oschin telescope in 1986. Before that it was just called the 48-inch Schmidt.[1]
The camera has been converted to use a CCD imager. This is a mosaic of 12 CCDs covering the whole (4 degree by 4 degree) field of view of the camera, the largest CCD mosaic used in an astronomical camera at this time. The corrector plate was recently replaced using glass that is transparent to a wider range of wavelengths. The camera was originally hand-guided through one of two 10-inch-aperture (0.25 m) refracting telescopes mounted on either side of the camera. The camera is now fully automated and remote-controlled. The data collected is transmitted over the High Performance Wireless Research and Education Network (HPWREN). It is programmed and operated primarily from Pasadena, California, with no operator on site (except to open and close the dome).
About half of the large photographic glass plate negatives exposed on the telescope, some 19,000 in all, had been accumulating in the sub-basement of the Robinson building at the California Institute of Technology since 1949. In 2002, astronomer Jean Mueller approached Richard Ellis, the director of the Caltech Optical Observatories, to volunteer to the task of organizing the Oschin Telescope plate archive. Given the go-ahead, she recruited eleven volunteers from the Mount Wilson Observatory Association (MWOA) and the Los Angeles Astronomical Society (LAAS), and the team then spent 13 weekends (more than one thousand hours) poring over the stacks, placing plates in protective sleeves, and packing them in more than 500 boxes that were transported to Palomar.