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Apache Point Observatory

The Apache Point Observatory (APO; obs. code: 705) is an astronomical observatory located in the Sacramento Mountains in Sunspot, New Mexico, United States, approximately 18 miles (29 km) south of Cloudcroft. The observatory is operated by New Mexico State University (NMSU) and owned by the Astrophysical Research Consortium (ARC). Access to the telescopes and buildings is private and restricted.[1]

Apache Point Observatory
ARCSAT and SDSS telescope buildings at the Apache Point Observatory.
OrganizationAstrophysical Research Consortium
Observatory code 705 Edit this on Wikidata
LocationSunspot, New Mexico
Coordinates32°46′49″N 105°49′13″W / 32.78028°N 105.82028°W / 32.78028; -105.82028Coordinates: 32°46′49″N 105°49′13″W / 32.78028°N 105.82028°W / 32.78028; -105.82028
Altitude2,788 meters (9,147 ft)
Weather65% clear nights
Established1985 (1985)
Astrophysical Research Consortium telescope3.5 m reflector
Sloan Digital Sky Survey telescope2.5 m reflector
New Mexico State University telescope1.0 m reflector
ARCSAT0.5 m reflector
Apache Point Observatory is located in the United States
Apache Point Observatory
Location of Apache Point Observatory
Commons page Related media on Wikimedia Commons


The ARC was formed in 1984 with the goal of building the 3.5 m telescope. It originally consisted of five institutions: New Mexico State University, University of Washington, University of Chicago, Princeton University, and Washington State University, which has since withdrawn.

Five additional organizations have joined over time: the Institute for Advanced Study, Johns Hopkins University, University of Colorado, University of Virginia, and Georgia State University. Funding for the 3.5 m and 0.5 m telescopes comes from consortium, but funds for the 2.5 m telescope come from a much wider array of sources. The 1.0 m telescope is supported exclusively by NMSU.[2]


ARC 3.5 mEdit

The ARC 3.5-meter telescope

The ARC 3.5 m (140 in) telescope is a Ritchey-Chretien reflector on an alt-azimuth mount with instruments attached at several focal points. Construction of the building began in 1985, but full operations of the telescope were delayed until November 1994 due to problems with fabricating the primary mirror.[3] From 1991 until early 1993 the telescope was fitted with a 1.8 m mirror now located at Rothney Astrophysical Observatory under a cost-sharing agreement.[4][5]

There are a variety of optical and near-infrared instruments available for the 3.5 m telescope, including:

  • The ARC echelle spectrometer (ARCES) uses a 2048 x 2048 pixel CCD and has a resolution of R~31,500.[6]
  • The Double Imaging Spectrometer (DIS) is a low-resolution optical spectrometer.[7]
  • The Near Infrared Camera/Fabry–Pérot Spectrometer (NICFPS) 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-Pérot devices in that it is cooled with liquid nitrogen.[8]
  • The Seaver Prototype Imaging camera (SPIcam) is an optical imaging instrument with a 2048x2048 pixel CCD.[9]
  • TripleSpec (Tspec) is a near infrared spectrograph which provides continuous wavelength coverage over the range 0.94–2.46 µm at moderate resolution (R~3500, depending on the choice of slit).[10]

The 3.5 m telescope is also used by the Apache Point Observatory Lunar Laser-ranging Operation (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.[11][12]

Observations using the 3.5 m telescope can be carried out remotely by observers using TUI, the Telescope User Interface, via the internet.[13]

SDSS 2.5 mEdit

Enclosure of the SDSS

The SDSS 2.5 m (98 in) telescope is used for the Sloan Digital Sky Survey, and began operating in 2000. It is a Ritchey-Chretien reflector on an alt-azimuth mount housed under a roll-off enclosure. It was designed with an unusually large 3° field of view to better support its primary task of surveying the entire sky.[14]

NMSU 1.0 mEdit

The NMSU 1.0 m (39 in) telescope is a Ritchey-Chretien reflector set on an alt-azimuth mount, and was completed in 1994.[15][16] A 2048x2048 CCD mounted at the Nasmyth focus provides at 15.7 arcminute view of the sky.[17]

0.5 m ARCSATEdit

The ARC Small Aperture Telescope (ARCSAT) was previously called the Photometric Telescope (PT) when it was part of the SDSS project. It is a 0.5 m (20 in) reflecting telescope on an equatorial mount, with a single CCD camera cooled by a CryoTiger unit.[18] It was built in 1991, moved from its previous location in 1998, and used by the SDSS until 2005.[19] It is currently used for small research projects.

Former telescopesEdit

  • A 0.6 m (24 in) reflecting telescope was built in 1993 to monitor sky conditions for the SDSS project. It never operated in a satisfactory manner, and was replaced with the 0.5 m PT.[19]

List of discovered minor planetsEdit

The Minor Planet Center credits the discovery of the following minor planets directly to the Apache Point Observatory:[20]

(227119) 2005 ND85 3 July 2005 list
(245170) 2004 TE116 4 October 2004 list
(254369) 2004 TD116 4 October 2004 list
(268095) 2004 RJ257 9 September 2004 list
(271691) 2004 RW106 9 September 2004 list
(271801) 2004 TD78 4 October 2004 list
(283979) 2004 RN170 8 September 2004 list
(399680) 2004 TP21 4 October 2004 list
(427855) 2005 NN67 3 July 2005 list

See alsoEdit


  1. ^ "Public Access and Tours". Apache Point Observatory. 20 August 2018.
  2. ^ Holtzman, Jon; et al. (2009-03-15). Apache Point Observatory: Facilities, Operations, and Partnerships. Astro2010: The Astronomy and Astrophysics Decadal Survey (Report). National Academies. Retrieved 2012-01-14.
  3. ^ Peterson, Jim. "A Brief History of the Astrophysical Research Consortium (ARC) and the Apache Point Observatory (APO)". Apache Point Observatory. Archived from the original on 2011-08-11. Retrieved 2012-01-07.
  4. ^ "Annual Reports of Astronomical Observatories and Departments: Apache Point Observatory, Astrophysical Research Consortium". Bulletin of the American Astronomical Society. 24: 17. 1992. Bibcode:1992BAAS...24...17.
  5. ^ York, D. G. (1994). "University of Chicago, Apache Point Observatory/Department of Astronomy and Astrophysics, Chicago, Illinois 60637". Bulletin of the Astronomical Society. 26 (1): 58. Bibcode:1994BAAS...26...58Y.
  6. ^ "ARC 3.5m | ARCES (Echelle)". Apache Point Observatory. Retrieved 2012-01-07.
  7. ^ "ARC 3.5m | DIS". Apache Point Observatory. Retrieved 2012-01-07.
  8. ^ "ARC 3.5m | NICFPS". Apache Point Observatory. Retrieved 2012-01-07.
  9. ^ "ARC 3.5m | SPIcam". Apache Point Observatory. Retrieved 2012-01-07.
  10. ^ "ARC 3.5m | TripleSpec". Apache Point Observatory. Retrieved 2012-01-07.
  11. ^ "APOLLO". Apache Point Observatory Lunar Laser-ranging Operation. Retrieved 2012-01-07.
  12. ^ Battat, J. B. R.; Murphy, T. W.; Adelberger, E. G.; Gillespie, B.; Hoyle, C. D.; McMillan, R. J.; Michelsen, E. L.; Nordtvedt, K.; Orin, A. E.; Stubbs, C. W.; Swanson, H. E. (1 January 2009). "The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO): Two Years of Millimeter-Precision Measurements of the Earth-Moon Range1". Publications of the Astronomical Society of the Pacific. 121 (875): 29–40. Bibcode:2009PASP..121...29B. doi:10.1086/596748.
  13. ^ "TUI Telescope User Interface". Apache Point Observatory. Retrieved 2012-01-07.
  14. ^ Gunn, James E.; et al. (1 April 2006). "The 2.5 m Telescope of the Sloan Digital Sky Survey". The Astronomical Journal. 131 (4): 2332–2359. arXiv:astro-ph/0602326. Bibcode:2006AJ....131.2332G. doi:10.1086/500975.
  15. ^ Holtzman, Jon A.; Harrison, Thomas E.; Coughlin, Jeffrey L. (1 January 2010). "The NMSU 1 m Telescope at Apache Point Observatory". Advances in Astronomy. 2010: 193086. Bibcode:2010AdAst2010E..46H. doi:10.1155/2010/193086.
  16. ^ "Annual Reports of Astronomical Observatories and Departments: Astrophysical Research Consortium, Apache Point Observatory". Bulletin of the American Astronomical Society. 27: 9. 1995. Bibcode:1995BAAS...27....9.
  17. ^ "APO 1m telescope Home Page". Apache Point Observatory. Retrieved 2012-01-07.
  18. ^ "Astrophysical Research Consortium Small Aperture Telescope". Apache Point Observatory. Retrieved 2012-01-07.
  19. ^ a b "History of the 20-inch Telescope". Apache Point Observatory. Retrieved 2012-01-07.
  20. ^ "Minor Planet Discoverers (by number)". Minor Planet Center. 14 November 2016. Retrieved 29 November 2016.

External linksEdit