| Apache Point Observatory | |||||||||
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| Organization | Astrophysical Research Consortium (ARC) | ||||||||
| Location | Sunspot, New Mexico, USA | ||||||||
| Altitude | 2,788 m (9,147 ft) | ||||||||
| Website www.apo.nmsu.edu |
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The Apache Point Observatory (APO) is located in the Sacramento Mountains in Sunspot, New Mexico (USA) 18 miles south of Cloudcroft. The observatory consists of the Astrophysical Research Consortium's (ARC) 3.5-meter telescope, the Sloan Digital Sky Survey 2.5-m telescope with a 20" photometric telescope, and New Mexico State University's 1.0-m telescope. Access to the telescopes and buildings is restricted, but the public is welcomed to stroll the grounds. The visitor's center at Sun Spot (the National Solar Observatory) includes a model of Apache Point's 3.5 meter telescope and actual filter plates for the Sloan telescope.
The 3.5 m telescope hosts the APOLLO lunar-ranging project. The APOLLO laser has been operational since October 2005, and routinely accomplishes millimeter-level range accuracy between the earth and the moon.
Observations at APO are often carried out remotely by observers using TUI, the Telescope User Interface, via the internet.
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There are a variety of optical and near-infrared instruments at APO.
The Near Infrared Camera/Fabry–Pérot Spectrometer was developed at the University of Colorado. It uses a 1024x1024 H1RG HgCdTe infrared detector and a near-infrared Fabry–Pérot interferometer. It has many narrow band filters, including H2, [Fe II], and [SiVI]. It is unique among astronomical Fabry-Perot devices in that it is cooled with liquid nitrogen.
The Double Imaging Spectrometer is a low-resolution optical spectrometer.
The echelle spectrometer at APO uses a 2048 x 2048 pixel CCD and has a resolution of 30,000.
The Seaver Prototype Imaging camera is an optical imaging instrument with a 2048x2048 pixel CCD.
TripleSpec is a near infrared spectrograph which provides continuous wavelength coverage over the range 0.94-2.46 microns at moderate resolution (R~3500, depending on the choice of slit).
The Photometric Telescope, or PT, is an (usually) automated telescope used by the Sloan Digital Sky Survey (SDSS). The telescope is a 20" reflector telescope with a single CCD camera, cooled by a CryoTiger unit.
During normal operations of the SDSS 2.5m telescope the PT is under automated control. While the SDSS obtains photometric or spectroscopic data, the PT will image patches of the sky that lie along the drift paths of the SDSS. These patches are used to calibrate the SDSS data, correcting for nightly atmospheric extinction as well as calibrating the data to the ugriz photometric system zero points. This process is required because while the ugriz system is tied to USNO standard stars, the SDSS cannot image directly these stars because they are too bright. Instead the PT records transfer patches which are compared to SDSS data.
The PT uses u'g'r'i'z' filters. These filters were intended to be identical to the SDSS ugriz, however physical differences do exist. Works is ongoing to accurately tie the PT to the SDSS, which is important for the future use of SDSS.