Editing Apache Point Observatory

{{Infobox Observatory
|name            = Apache Point Observatory
|image           = [[File:apache-0110.JPG|250px|]]
|caption         = {{longitem|ARCSAT and [[Sloan Digital Sky Survey|SDSS]] telescope buildings at the Apache Point Observatory.|style=padding: 5px; line-height: 1.4em;}}
|organization    = Astrophysical Research Consortium
|code            = 
|location        = [[Sunspot, New Mexico]]
|coords          = {{coord|32|46|49|N|105|49|13|W|type:landmark|display=inline,title}}
|altitude        = {{convert|2788|m|ft|sp=us}}
|weather         = 65% clear nights
|established     = {{Start date|1985}}
|closed          = 
|website         = {{URL|http://www.apo.nmsu.edu/}} 
|telescope1_name = Astrophysical Research Consortium telescope
|telescope1_type = 3.5&nbsp;m reflector
|telescope2_name = [[Sloan Digital Sky Survey]] telescope
|telescope2_type = 2.5&nbsp;m reflector
|telescope3_name = [[New Mexico State University]] telescope
|telescope3_type = 1.0&nbsp;m reflector
|telescope4_name = ARCSAT
|telescope4_type = 0.5&nbsp;m reflector
}}

The '''Apache Point Observatory''' (APO; [[List of observatory codes|obs. code]]: [[IAU code#705|705]]) is an [[astronomy|astronomical]] [[observatory]] located in the [[Sacramento Mountains (New Mexico)|Sacramento Mountains]] in [[Sunspot, New Mexico|Sunspot]], [[New Mexico]], United States, approximately {{convert|18|miles|km|sp=us}} south of [[Cloudcroft, New Mexico|Cloudcroft]]. The observatory is operated by [[New Mexico State University]] (NMSU) and owned by the Astrophysical Research Consortium (ARC).<ref>{{Cite web |last=Peterson |first=Jim |title=A Brief History of the Astrophysical Research Consortium (ARC) and the Apache Point Observatory (APO) |url=https://arc.apo.nmsu.edu/ARC-History.pdf |access-date=10 May 2025 |website=Astrophysical Research Consortium}}</ref> Access to the telescopes and buildings is private and restricted.<ref name="APOTOUR" />

== History ==

The ARC was formed in 1984 with the goal of building the 3.5&nbsp;m telescope. It originally consisted of five institutions: [[New Mexico State University]], [[University of Washington]], [[University of Chicago]], [[Princeton University]], and [[Washington State University]], some of which have since withdrawn.{{cn|date=December 2021}}

Several additional organizations have joined over time: [[Johns Hopkins University]], [[University of Colorado]], [[University of Virginia]], [[Georgia State University]], [[University of Oklahoma]], [[University of Wyoming]], and [[Brigham Young University]]. Funding for the 3.5&nbsp;m and 0.5&nbsp;m telescopes comes from the consortium members, but funds for the 2.5&nbsp;m telescope come from a much wider array of sources. The 1.0&nbsp;m telescope is supported exclusively by NMSU.<ref name="2009HOLT" />

{{clear|left}}

== Telescopes ==

=== ARC 3.5 m ===
[[File:D70050914 15 ApolloLLR.jpg|thumb|upright|The ARC 3.5-meter telescope]]

The ARC {{convert|3.5|m|in|abbr=on}} telescope is a [[Ritchey-Chretien]] reflector on an [[alt-azimuth mount]] with instruments attached at several [[Focus (optics)|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]].<ref name="APOHIST" /> From 1991 until early 1993, the telescope was fitted with a 1.8&nbsp;m mirror, now located at [[Rothney Astrophysical Observatory]] under a [[cost-sharing agreement]].<ref name="REP92" /><ref name="REP94" />

There are a variety of optical and near-infrared instruments available for the 3.5 m telescope, including:
* The ARC [[echelle grating|echelle spectrometer]] (ARCES) uses a 2048 × 2048 pixel [[Charge-coupled device|CCD]] and has a [[spectral resolution|resolution]] of <math>R\sim 31{,}500</math>.<ref name="ARCES" />
* The Double Imaging Spectrometer (DIS) is a low-resolution optical spectrometer.<ref name="DIS" />
*KOSMOS, on long-term loan from NOIRLab, is a low-resolution optical spectrometer.
* The Near Infrared Camera/Fabry–Pérot Spectrometer (NICFPS) was developed at the [[University of Colorado at Boulder|University of Colorado]]. It uses a 1024 × 1024 H1RG [[HgCdTe]] infrared detector and a near-infrared [[Fabry–Pérot interferometer]]. It has many narrow band filters, including [[Molecular cloud|H2]], [[forbidden line|[Fe II]]], and [SiVI]. It is unique among astronomical Fabry-Pérot devices in that it is cooled with [[liquid nitrogen]].<ref name="NICFPS" />
* The Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) is an optical imaging instrument with a 4096 × 4096 pixel CCD.<ref>{{cite web | url=https://www.apo.nmsu.edu/arc35m/Instruments/ARCTIC/ | title=ARC 3.5m {{pipe}} Arctic }}</ref>
* TripleSpec (Tspec) is a near infrared spectrograph which provides continuous wavelength coverage over the range 0.94–2.46&nbsp;[[μm]] at moderate resolution (<math>R\sim 3500</math>, depending on the choice of slit).<ref name="TSPEC" />
*Agile is a high-speed imager with a 1024 x 1024 frame transfer CCD.{{cn|date=December 2021}}

The 3.5&nbsp;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.<ref name="APLO" /><ref name="2009BATT" />

Observations using the 3.5&nbsp;m telescope can be carried out remotely by observers using TUI, the Telescope User Interface, via the internet.<ref name="TUI" />

=== SDSS 2.5 m ===
[[File:SDSS (Crop of Apache-0110).JPG|thumb|upright|Enclosure of the SDSS]]

The SDSS {{convert|2.5|m|in|abbr=on}} 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 [[Astronomical survey|surveying]] the entire sky.<ref name="SDSS25" />

=== NMSU 1.0 m ===

The NMSU {{convert|1.0|m|in|abbr=on}} telescope is a Ritchey-Chretien reflector set on an alt-azimuth mount, and was completed in 1994.<ref name="2010HOLT" /><ref name="REP95" /> A 2048 × 2048 CCD mounted at the [[Nasmyth focus]] provides at 15.7 arcminute view of the sky.<ref name="1M" />

=== 0.5 m ARCSAT ===

The ARC Small Aperture Telescope (ARCSAT) was previously called the Photometric Telescope (PT) when it was part of the SDSS project.  It is a {{convert|0.5|m|in|abbr=on}} reflecting telescope on an [[equatorial mount]], with a single CCD camera cooled by a CryoTiger unit.<ref name="20IN" />  It was built in 1991, moved from its previous location in 1998, and used by the SDSS until 2005.<ref name="20INHIST" />  It is currently used for small research projects.

=== Former telescopes ===

* A {{convert|0.6|m|in|abbr=on}} 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&nbsp;m PT.<ref name="20INHIST" />

== List of discovered minor planets ==

The [[Minor Planet Center]] credits the discovery of the following [[minor planet]]s directly to the Apache Point Observatory:<ref name="MPC-Discoverers" />
{| class="wikitable" style="font-size: 89%; float: left; width: 25em; margin-right: 1em; line-height: 1.65em !important; height: 120px;"
|-
| {{mp|(227119) 2005 ND|85}} || 3 July 2005|| {{small|{{LoMP|227119|list}}}}
|-
| {{mp|(245170) 2004 TE|116}} || 4 October 2004|| {{small|{{LoMP|245170|list}}}}
|-
| {{mp|(254369) 2004 TD|116}} || 4 October 2004|| {{small|{{LoMP|254369|list}}}}
|-
| {{mp|(268095) 2004 RJ|257}} || 9 September 2004|| {{small|{{LoMP|268095|list}}}}
|-
| {{mp|(271691) 2004 RW|106}} || 9 September 2004|| {{small|{{LoMP|271691|list}}}}
|}
{| class="wikitable" style="font-size: 89%; float: left; width: 25em; margin-right: 1em; line-height: 1.65em !important; height: 120px;"
|-
| {{mp|(271801) 2004 TD|78}} || 4 October 2004|| {{small|{{LoMP|271801|list}}}}
|-
| {{mp|(283979) 2004 RN|170}} || 8 September 2004|| {{small|{{LoMP|283979|list}}}}
|-
| {{mp|(399680) 2004 TP|21}} || 4 October 2004|| {{small|{{LoMP|399680|list}}}}
|-
| {{mp|(427855) 2005 NN|67}} || 3 July 2005|| {{small|{{LoMP|427855|list}}}}
|}
{{clear}}

== See also ==
* [[List of astronomical observatories]]
* [[List of largest optical reflecting telescopes]]
* {{Section link|List of minor planet discoverers|Discovering dedicated institutions}}
* [[Sunspot Solar Observatory]]

== References ==
{{reflist|refs=
<ref name="APOTOUR">{{cite web |title=Public Access and Tours |url=http://www.apo.nmsu.edu/Planning/PublicInfo/083007Tours.html |publisher=Apache Point Observatory |date = 20 August 2018}}</ref>
<ref name="2009HOLT">{{cite report |title=Apache Point Observatory: Facilities, Operations, and Partnerships |last=Holtzman |first=Jon |url=http://www8.nationalacademies.org/astro2010/DetailFileDisplay.aspx?id=438 |date=2009-03-15 |work=Astro2010: The Astronomy and Astrophysics Decadal Survey |publisher=[[National Academies]] |access-date=2012-01-14|display-authors=etal}}</ref>
<ref name="APOHIST">{{cite web|title=A Brief History of the Astrophysical Research Consortium (ARC) and the Apache Point Observatory (APO) |url=http://arc.apo.nmsu.edu/arc/ARC-History.html |publisher=Apache Point Observatory |author=Peterson, Jim |access-date=2012-01-07 |url-status=dead |archive-url=https://web.archive.org/web/20110811164946/http://arc.apo.nmsu.edu/arc/ARC-History.html |archive-date=2011-08-11}}</ref>
<ref name="REP92">{{cite journal|bibcode=1992BAAS...24...17.|title=Annual Reports of Astronomical Observatories and Departments: Apache Point Observatory, Astrophysical Research Consortium|volume=24|year=1992|pages=17|journal=Bulletin of the American Astronomical Society}}</ref>
<ref name="REP94">{{cite journal|bibcode=1994BAAS...26...58Y|title=University of Chicago, Apache Point Observatory/Department of Astronomy and Astrophysics, Chicago, Illinois 60637|last1=York|first1=D. G.|volume=26|issue=1|year=1994|pages=58|journal=Bulletin of the Astronomical Society}}</ref>
<ref name="ARCES">{{cite web|title=ARC 3.5m {{!}} ARCES (Echelle)|url=http://www.apo.nmsu.edu/arc35m/Instruments/ARCES/ |publisher=Apache Point Observatory|access-date=2012-01-07}}</ref>
<ref name="DIS">{{cite web|title=ARC 3.5m {{!}} DIS|url=http://www.apo.nmsu.edu/arc35m/Instruments/DIS/|publisher=Apache Point Observatory|access-date=2012-01-07}}</ref>
<ref name="NICFPS">{{cite web|title=ARC 3.5m {{!}} NICFPS |url=http://www.apo.nmsu.edu/arc35m/Instruments/NICFPS/ |publisher=Apache Point Observatory|access-date=2012-01-07}}</ref>
<ref name="TSPEC">{{cite web |title=ARC 3.5m {{!}} TripleSpec |url=http://www.apo.nmsu.edu/arc35m/Instruments/TRIPLESPEC/ |publisher=Apache Point Observatory|access-date=2012-01-07}}</ref>
<ref name="APLO">{{cite web |title=APOLLO |url=http://physics.ucsd.edu/~tmurphy/apollo/apollo.html |publisher=Apache Point Observatory Lunar Laser-ranging Operation |access-date=2012-01-07}}</ref>
<ref name="2009BATT">{{cite journal |last1=Battat |first1=J. B. R. |last2=Murphy|first2= T. W.|last3= Adelberger|first3= E. G.|last4= Gillespie|first4= B.|last5= Hoyle|first5= C. D.|last6= McMillan|first6= R. J.|last7= Michelsen|first7= E. L.|last8= Nordtvedt|first8= K.|last9= Orin|first9= A. E.|last10= Stubbs|first10= C. W.|last11= Swanson|first11= H. E. |title=The Apache Point Observatory Lunar Laser-ranging Operation (APOLLO): Two Years of Millimeter-Precision Measurements of the Earth-Moon Range1 |journal=Publications of the Astronomical Society of the Pacific |date=1 January 2009 |volume=121 |issue=875 |pages=29–40 |doi=10.1086/596748|bibcode = 2009PASP..121...29B |doi-access= free}}</ref>
<ref name="TUI">{{cite web |title=TUI Telescope User Interface |url=http://www.apo.nmsu.edu/35m_operations/TUI/ |publisher=Apache Point Observatory |access-date=2012-01-07}}</ref>
<ref name="SDSS25">{{cite journal |last=Gunn |first=James E. |title=The 2.5 m Telescope of the Sloan Digital Sky Survey |journal=The Astronomical Journal |date=1 April 2006 |volume=131 |issue=4 |pages=2332–2359 |doi=10.1086/500975|arxiv = astro-ph/0602326 |bibcode = 2006AJ....131.2332G |s2cid=7080617 |display-authors=etal}}</ref>
<ref name="2010HOLT">{{cite journal |last=Holtzman |first=Jon A. |author2=Harrison, Thomas E.|author3=Coughlin, Jeffrey L. |title=The NMSU 1 m Telescope at Apache Point Observatory |journal=Advances in Astronomy |date=1 January 2010 |volume=2010 |pages=193086 |doi=10.1155/2010/193086 |bibcode = 2010AdAst2010E..46H |doi-access=free}}</ref>
<ref name="1M">{{cite web |title=APO 1m telescope Home Page |url=http://nmsu1m.apo.nmsu.edu/1m/ |publisher=Apache Point Observatory |access-date=2012-01-07}}</ref>
<ref name="REP95">{{cite journal|bibcode=1995BAAS...27....9.|title=Annual Reports of Astronomical Observatories and Departments: Astrophysical Research Consortium, Apache Point Observatory|volume=27|year=1995|pages=9|journal=Bulletin of the American Astronomical Society}}</ref>
<ref name="20IN">{{cite web |title=Astrophysical Research Consortium Small Aperture Telescope |url=http://users.apo.nmsu.edu/~arcsat/arcsat_mission.html |publisher=Apache Point Observatory |access-date=2012-01-07}}</ref>
<ref name="20INHIST">{{cite web |title=History of the 20-inch Telescope |url=http://users.apo.nmsu.edu/~arcsat/PT/History/index.html |publisher=Apache Point Observatory |access-date=2012-01-07}}</ref>
<ref name="MPC-Discoverers">{{cite web |title = Minor Planet Discoverers (by number) |work = Minor Planet Center |url = http://www.minorplanetcenter.net/iau/lists/MPDiscsNum.html |date = 14 November 2016 |access-date = 29 November 2016}}</ref>
}}

== External links ==
{{commons category|Apache Point Observatory}}
* [http://astronomy.nmsu.edu/ Astronomy Department] at NMSU
* [http://www.sdss.org Sloan Digital Sky Survey homepage]
* [http://cleardarksky.com/c/ApachePtNMkey.html Apache Point Clear Sky Clock] Forecasts of observing conditions.

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