United States Naval Observatory Flagstaff Station

United States Naval Observatory Flagstaff Station
Organization United States Naval Observatory
Code 689
Location Coconino County, near Flagstaff, Arizona
Coordinates 35°11′03″N 111°44′25″W / 35.18417°N 111.74028°W / 35.18417; -111.74028
Altitude 2,273 metres (7,457 ft)
Established 1955
Website http://www.nofs.navy.mil/
Telescopes
Kaj Strand Telescope 1.55 m (61 in) reflector
DFM/Kodak/Corning 1.3 m reflector
Unnamed telescope 1.0 m (40 in) Ritchey-Chretien reflector
Flagstaff Astrometric Scanning Transit Telescope 8-inch (20 cm) catadioptric
Navy Precision Optical Interferometer interferometer (Located at Anderson Mesa)

The United States Naval Observatory Flagstaff Station (NOFS), is an astronomical observatory near Flagstaff, Arizona, USA. It is the national dark-sky observing facility under the United States Naval Observatory (USNO).[1] NOFS and USNO combine as the Celestial Reference Frame[2] manager for the U.S. Secretary of Defense.[3][4]

General information

The Flagstaff Station is a command which was established by USNO (due to a century of eventually untenable light encroachment in Washington, D.C.) at a site five miles west of Flagstaff, Arizona in 1955, and has positions for primarily operational scientists (astronomers and astrophysicists), optical and mechanical engineers, and support staff.

NOFS science supports every aspect of positional astronomy to some level, providing national support and beyond. Work at NOFS covers the gamut of astrometry and astrophysics in order to facilitate its production of accurate/precise astronomical catalogs. Also, owing to the celestial dynamics (and relativistic effects[5]) of the huge number of such moving objects across their own treks through space, the time expanse required to pin down each set of celestial locations and motions for a perhaps billion-star catalog, can be quite long. Multiple observations of each object may themselves take weeks, months or years, by themselves. This, multiplied by the large number of cataloged objects that must then be reduced for use, and which must be analyzed after observation for a very careful statistical understanding of all catalog errors, forces the rigorous production of most extremely precise and faint astrometric catalogs to take many years, sometimes decades, to complete.

Night-time panoramic of operations at the United States Naval Observatory Flagstaff Station (NOFS)
Dark-sky operations at the United States Naval Observatory Flagstaff Station (NOFS)

.


The United States Naval Observatory, Flagstaff Station celebrated its 50th anniversary of the move there from Washington, D.C. in late 2005.[6] Dr. John Hall, Director of the Naval Observatory's Equatorial Division from 1947, founded NOFS. Dr. Art Hoag became its first director in 1955 (until 1965); both later were to also become directors of nearby Lowell Observatory.[7]

NOFS remains active in supporting regional dark skies,[8][9] both to support its national protection mission,[10][11] and to promote and protect a national resource legacy for generations of humans to come.[12][13][14]

Site description

NOFS is adjacent to Northern Arizona's San Francisco Peaks, on the alpine Colorado Plateau and geographically above the Mogollon Rim.Flagstaff and Coconino County minimize northern Arizona light pollution[15] through legislation of progressive code – which regulates local lighting.[16][17][18][19][20][21][22][23] Indeed, despite a half-century-young history, NOFS has a rich heritage[24] which is derived from its parent organization, USNO, the oldest scientific institution in the U.S.[25] At an elevation of approximately 7500 feet, NOFS is home to a number of astronomical instruments[26] (some also described in the worldwide list of optical telescopes); some additional instrumentation is on nearby Anderson Mesa:

[27][28]

Kaj Strand Telescope

Congressionally appropriated in 1961, the 61-inch Kaj Strand Telescope (or 1.55-m Kaj Strand Astrometric Reflector, KSAR) remains largest telescope operated by the U.S. Navy since it saw first light in 1964.[29] This status will change when the NPOI four 1.8-meter telescopes see their own first light in the near future. KSAR rides in the arms of an equatorial fork mount. The telescope is used in both the visible spectrum, and in the near infrared (NIR),[30] the latter using a sub-30-Kelvin, helium-refrigerated, InSb (Indium antimonide) camera, "Astrocam".[31] In 1978, the 1.55-m telescope was used to "discover the moon of dwarf planet Pluto, named 'Charon'". (Pluto itself was discovered in 1930, across town at Lowell Observatory). The Charon discovery led to mass calculations which ultimately revealed how tiny Pluto was, and eventually caused the IAU to reclassify Pluto as a dwarf (not a principle) planet.[32][33][34] The 1.55-meter telescope was also used to observe and track NASA's Deep Impact Spacecraft, as it navigated to a successful inter-planetary impact with the celebrated Comet 9p/Tempel, in 2005. This telescope is particularly well-suited to perform stellar parallax studies, narrow-field astrometry supporting space navigation, and has also played a key role in discovering one of the coolest-ever known brown dwarf objects, in 2002.[35] The 61" dome is centrally located on NOFS grounds, with support and office buildings attached to the dome structures. The large vacuum coating chamber facility is also located in this complex. The chamber can provide very accurate coatings and overcoatings of 100 (+/-2) Angstrom thickness (approximately 56 aluminium atoms thick), for small-to-multi-ton optics up to 72-inches (1.82 meters) in diameter, in a vacuum exceeding 7×106 Torr, using a vertical-optic, 1500-ampere discharge system. A dielectric coating capability has also been demonstrated. Large optics and telescope components can be moved about NOFS using its suite of cranes, lifts, cargo elevators and specialized carts. The main complex also contains a controlled-environment, optical and electronics lab for laser, adaptive optics, optics development, collimation, mechanical, and micro-electronic control systems needed for NOFS and NPOI.

The KSAR Telescope's 60-foot diameter steel dome is quite large for the telescope's aperture, owing to its telescope's long f/9.8 focal ratio (favorable for very accurate optical collimation, or alignment, needed for astrometric observation). It uses a very wide 2-shutter, vertical slit. Development studies have taken place to successfully show that planned life-cycle replacement of this venerable instrument can be efficiently done within the original dome, for a future telescope with an aperture of up to 3.6-meters, by using fast, modern-day optics.[36] However, the 61-inch telescope remains unique in its ability to operationally conduct both very high-accuracy relative astrometry to the milliarcsecond level, and close-separation, PSF photometry. Several key programs take advantage of this capability to this day.

1.3 m telescope

The 1.3 m (51-inch) large-field R-C telescope was produced by DFM Engineering and then corrected and automated by NOFS staff.[37] Corning Glass Works and Kodak made the primary mirror. The hyperbolic secondary has an advanced, computer-controlled collimation (alignment) system in order to permit very precise positions of stars and satellites (milliarcsecond astrometry) across its wide field of view. This system analyzes optical aberrations of the optical path, modeled by taking slope fits of the wavefront deviations revealed using a Hartmann mask. The telescope also now sports a state-of-the art, cryogenic wide-field mosaic CCD[38] camera.[39][40] It will also permit employment of the new "Microcam", an orthogonal transfer array (OTA), with Pan-STARRS heritage.[41][42][43][44] Other advanced camera systems are also deployed for use on this telescope, such as the LANL-produced RULLI single photon counter, nCam.[45][46][47][47][48][49][50] Using the telescope's special software controls, the telescope can track both stars and man-made satellites orbiting the Earth, while the camera images both. The 1.3 m dome itself is compact, owing to the fast overall optics at f/4. It is located near by and southwest of, the very large 61-inch dome. In addition to astrometric studies (such as for Space Situational Awareness, SDSS[51] and SST), research on this telescope includes the study of blue and K-Giant stars, celestial mechanics and dynamics of multiple star systems, characterizations of artificial satellites, and the astrometry and transit photometry of exoplanets. Astrometrically, exoplanets also confuse centroid of a parent star's PSF—and there are many exoplanets—so the impact of their not-bland dynamics must be understood.

1.0 m telescope

The '40-inch (1-meter) "Ritchey Telescope" is also an equatorially driven, fork-mounted telescope.[52] The Ritchey is the original Station telescope which was moved from USNO in Washington in 1955. It is also the first R-C telescope ever made from that famous optical prescription, and was coincidentally the last telescope built by George Ritchey himself. The telescope is still in operation after a half century of astronomy at NOFS. It performs key quasar-based reference frame operations, transit detections of exoplanets, Vilnius photometry, M-Dwarf star analysis, dynamical system analysis, reference support to orbiting space object information, horizontal parallax guide support to NPOI, and it performs photometric operations support to astrometric studies (along with its newer siblings). The 40-inch also can carry a number of liquid Nitrogen-cooled cameras, a coronagraph, and a nine-stellar magnitude neutral density spot focal plane array camera, through which star positions are cross-checked before use in fundamental NPOI reference frame astrometry. This telescope is also used to test internally developed optical adaptive optics (AO) systems, using tip-tilt and deformable mirror optics. The Shack-Hartmann AO system allows for corrections of the wavefront's aberrations caused by scintillation (degraded seeing), to higher Zernike polynomials. AO systems at NOFS will migrate to the 1.55m and 1.8m telescopes for future incorporation there.

The 40-inch dome is located at the summit and highest point of the modest mountain upon which NOFS is located. It is adjacent to a comprehensive instrumentation shop, which includes sophisticated, CAD-driven CNC fabrication machinery, and a broad array of design and support tooling.

0.2 m FASTT

A modern-day example of a fully robotic transit telescope is the small 0.2 m (8 in) Flagstaff Astrometric Scanning Transit Telescope (FASTT) located at the observatory.[53][54] FASTT provides extremely precise positions of solar system objects for incorporation into the USNO Astronomical Almanac and Nautical Almanac. These ephemerides are also used by NASA in the deep space navigation of its planetary and extra-orbital spacecraft. Instrumental to the navigation of many NASA deep space probes, this telescope is responsible for NASA JPL's successful 2005 navigation-to-landing of the Huygens Lander on Titan, a major moon orbiting Saturn, and is currently providing navigational reference for NASA's New Horizons deep space mission to Pluto, slated to arrive at the edge of the Solar System in July 2015.[55] FASTT has also been used help NASA's SOFIA Airborne Observatory correctly locate, track and image a rare Pluto occultation.[56] FASTT is located 150 yards southwest of the primary complex. Attached to its large "hut" is the building housing NOFS' electronics and electrical engineering laboratories and clean rooms, where most of the advanced camera electronics, cryogenics and telescope control drives are developed and made.

Navy Precision Optical Interferometer

NOFS operates the Navy Precision Optical Interferometer (NPOI)[57][58][59] (recently the "P" was modified to mean precision vice prototype) in collaboration with Lowell Observatory and the Naval Research Laboratory at Anderson Mesa, 15 miles south-east of Flagstaff. NOFS (the operational astrometric arm of USNO) funds all principle operations, and from this contracts Lowell Observatory to maintain the Anderson Mesa facility and make the observations necessary for NOFS to conduct the primary astrometric science. The Naval Research Laboratory (NRL) also provides additional funds to contract Lowell Observatory's and NRL's implementation of additional, long-baseline siderostat stations, facilitating NRL's primary scientific work, synthetic imaging (both celestial and of orbital satellites). The three institutions - USNO, NRL, and Lowell - each provide an executive to sit on an Operational Advisory Panel (OAP), which collectively guides the science and operations of the interferometer. The OAP commissioned the chief scientist and director of the NPOI to effect the science and operations for the Panel; this manager is a senior member of the NOFS staff and reports to the NOFS Director.

NPOI is a successful astronomical interferometer[60] of the venerable and proven Michelson Interferometer design. As noted, the majority of interferometric science and operations are funded and managed by NOFS; however, Lowell Observatory and NRL join in the scientific efforts through their fractions of time to use the interferometer; 85% Navy (NOFS and NRL); and 15% Lowell. NPOI is one of the few major instruments globally which can conduct optical interferometry.<ref[>http://usic.wikispaces.com/file/view/Armstrong_OpticalInterferometry_TEC_OIR.pdf "Ground-based Optical/Infrared Interferometry : High Resolution, High Precision Imaging"] Check |url= value (help) (PDF). Usic.wikispaces.com. Retrieved 2013-11-14. </ref>[61] See an illustration of its layout, at bottom. NOFS has used NPOI to conduct a wide and diverse series of scientific studies, beyond just the study of absolute astrometric positions of stars,;[62] additional NOFS science at NPOI includes the study of binary stars, Be Stars, Oblate stars, rapidly rotating stars, those with starspots, and the imaging of stellar disks (the first in history) and flare stars.[63] In 2007–2008, NRL with NOFS used NPOI to obtain first-ever closure phase image precursors of satellites orbiting in geostationary orbit.[64][65]

NPOI Layout
Navy Precision Optical Interferometer (NPOI) Layout

Gallery

References

  1. ↑ https://web.archive.org/20160131231447/http://www.usno.navy.mil/USNO. Archived from the original on 31 January 2016. Retrieved 18 February 2016. Missing or empty |title= (help)
  2. ↑ (PDF) https://web.archive.org/20120319234250/http://ad.usno.navy.mil/forum/kaplan1.pdf. Archived from the original (PDF) on 19 March 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  3. ↑ "MetEd » Module Description:The U.S. Naval Observatory: Mission, Products, and Services". Meted.ucar.edu. Retrieved 2013-11-14.
  4. ↑ (PDF) https://web.archive.org/20130222090224/http://doni.daps.dla.mil/Directives/09000%20General%20Ship%20Design%20and%20Support/09-400%20Command%20and%20Surveillance%20Systems%20Support/9420.1B.pdf. Archived from the original (PDF) on 22 February 2013. Retrieved 7 May 2012. Missing or empty |title= (help)
  5. ↑ (PDF) https://web.archive.org/20060211105847/http://ad.usno.navy.mil:80/forum/nelson.pdf. Archived from the original (PDF) on 11 February 2006. Retrieved 6 July 2012. Missing or empty |title= (help)
  6. ↑ Naval Observatory Flagstaff Station Celebrates First Half Century | SpaceRef – Your Space Reference. SpaceRef (30 September 2005). Retrieved 18 October 2011.
  7. ↑ (PDF) https://web.archive.org/20120314161802/http://www.phys-astro.sonoma.edu/people/faculty/tenn/TennLowellObsJAH2v10p65.pdf. Archived from the original (PDF) on 14 March 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  8. ↑ Christian B. Luginbuhl's Homepage. Nofs.navy.mil (11 April 2011). Retrieved 18 October 2011.
  9. ↑ http://azdailysun.com/news/local/govt-and-politics/news-analysis-dark-skies-helps-seal---vote-in/article_19a371de-7e76-11e3-a0a5-001a4bcf887a.html
  10. ↑ USNO Flagstaff Station Mission Statement. Nofs.navy.mil. Retrieved 18 October 2011.
  11. ↑ The USNO's Mission – Naval Oceanography Portal. Usno.navy.mil. Retrieved 18 October 2011.
  12. ↑ Flagstaff Dark Skies Coalition. Flagstaffdarkskies.org (7 September 2011). Retrieved 18 October 2011.
  13. ↑ Flag marks 50 years of dark skies. Azdailysun.com (14 April 2008). Retrieved 18 October 2011.
  14. ↑ IDAHome. Darksky.org. Retrieved 18 October 2011.
  15. ↑ http://web.archive.org/web/20150610223855/http://ptonline.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=PHTOAD000062000012000032000001&idtype=cvips&bypassSSO=1. Archived from the original on 10 June 2015. Retrieved 8 May 2011. Missing or empty |title= (help)
  16. ↑ (PDF) https://web.archive.org/20120821021952/http://www.coconino.az.gov/uploadedFiles/Community_Development/Section17.pdf. Archived from the original (PDF) on 21 August 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  17. ↑ (PDF) https://web.archive.org/20120317142355/http://docs.darksky.org/ordinance/City-Flagstaff-AZ-Ordinance.pdf. Archived from the original (PDF) on 17 March 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  18. ↑ (PDF) https://web.archive.org/20120323161924/http://www.flagstaffdarkskies.org/docs/9_%20Title10%20Chapter8%20-%20Signs%20and%20Lighting.PDF. Archived from the original (PDF) on 23 March 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  19. ↑ Flagstaff Dark Skies Coalition – Model Lighting Codes. Flagstaffdarkskies.org (5 September 2011). Retrieved 18 October 2011.
  20. ↑ "Astronomers fight back". Azdailysun.com. 2012-03-16. Retrieved 2013-11-14.
  21. ↑ "AZ astronomers make case for keeping billboard ban". ktar.com. Retrieved 2013-11-14.
  22. ↑ "Arizona lawmaker cites compromise on billboards". Azcentral.com. Retrieved 2013-11-14.
  23. ↑ "Astronomers, billboard firms find compromise on Arizona measure". Azcentral.com. Retrieved 2013-11-14.
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  25. ↑ USNO Flagstaff Station – History. Nofs.navy.mil. Retrieved 18 October 2011.
  26. ↑ U.S. Naval Observatory Flagstaff Telescopes. Nofs.navy.mil (12 May 2011). Retrieved 18 October 2011.
  27. ↑ "Lights out at U.S. Naval Observatory?". 2014-11-18. Retrieved 2014-11-19.
  28. ↑ "Flagstaff City Council approves new student housing, 5 to 2". Arizona Daily Sun. 2014-11-19. Retrieved 2014-11-19.
  29. ↑ U.S. Naval Observatory Flagstaff – 1.55-m Astrometric Reflector. Nofs.navy.mil (24 May 2001). Retrieved 18 October 2011.
  30. ↑
  31. ↑ Astrocam. Rsd-www.nrl.navy.mil. Retrieved 18 October 2011.
  32. ↑ 25th Anniversary of the Discovery of Pluto's Moon Charon | SpaceRef – Your Space Reference. SpaceRef (22 June 2003). Retrieved 18 October 2011.
  33. ↑ Pluto/Charon. Lasp.colorado.edu. Retrieved 18 October 2011.
  34. ↑ planet.html. Boulder.swri.edu. Retrieved 18 October 2011.
  35. ↑ Tytell, David. (2003-07-23) Coolest Star Ever – News from Sky & Telescope. SkyandTelescope.com. Retrieved 18 October 2011.
  36. ↑ The feasibility of replacing the U.S. Naval Observatory's 61-inch astrometric reflector with a 3.5 m telescope | Publications. SPIE. Retrieved 18 October 2011.
  37. ↑ U.S. Naval Observatory Flagstaff – 1.3-m Reflector. Nofs.navy.mil (17 March 2000). Retrieved 18 October 2011.
  38. ↑ Wehner`s Photoelectric CCD. Wehner.org (26 January 2004). Retrieved 18 October 2011.
  39. ↑ First Light for USNO 1.3-meter Telescope. Adsabs.harvard.edu. Retrieved 18 October 2011.
  40. ↑ Improved Astrometric Calibration Regions along the Celestial Equator. Adsabs.harvard.edu. Retrieved 18 October 2011.
  41. ↑ "Results from the Pan-STARRS Orthogonal Transfer Array (OTA)" (PDF). Stargrasp.org. Retrieved 2013-11-14.
  42. ↑ "CiteSeerX — Example". Citeseerx.ist.psu.edu. Retrieved 2013-11-14.
  43. ↑ Development of the orthogonal-transfer array. Adsabs.harvard.edu. Retrieved 18 October 2011.
  44. ↑ MIT Lincoln Laboratory: Orthogonal-Transfer Arrays. Ll.mit.edu. Retrieved 18 October 2011.
  45. ↑ Remote ultra-low light imaging (RULLI) for space situational awareness (SSA): modeling and simulation results for passive and active SSA | Publications. SPIE. Retrieved 18 October 2011.
  46. ↑ https://web.archive.org/20110807053514/http://pearl1.lanl.gov/external/c-cde/rulli/. Archived from the original on 7 August 2011. Retrieved 18 February 2016. Missing or empty |title= (help)
  47. 1 2 Rulli (U). Fas.org. Retrieved 18 October 2011.
  48. ↑ "Science Applications of the RULLI Camera" (PDF). Amostech.com. Retrieved 2013-11-14.
  49. ↑ "From Sensing to Information : Everything Under the Sun" (PDF). Faculty.physics.tamu.edu. Retrieved 2013-11-14.
  50. ↑ "Remote Ultra-Low Light Imaging (RULLI) for Space Situational Awareness (SSA)". Permalink.lanl.gov. Retrieved 2013-11-14.
  51. ↑ 2005ASPC..338..201I Page 201. Adsabs.harvard.edu. Retrieved 18 October 2011.
  52. ↑ U.S. Naval Observatory Flagstaff – 1.0-m Ritchey-Chretien Reflector. Nofs.navy.mil (25 January 1998). Retrieved 18 October 2011.
  53. ↑ U.S. Naval Observatory Flagstaff – 0.2-m FASTT. Nofs.navy.mil (3 March 1999). Retrieved 18 October 2011.
  54. ↑ "Stone et al., Upgrades to the FASTT". Iopscience.iop.org. Retrieved 2013-11-14.
  55. ↑ "The Planetry and Lunar Ephemeris DE 421" (PDF). Tmo.jpl.nasa.gov. Retrieved 2013-11-14.
  56. ↑ (PDF) https://web.archive.org/20120916002229/http://www.usno.navy.mil/USNO/tours-events/NOFS_SOFIA_Release_110711.pdf. Archived from the original (PDF) on 16 September 2012. Retrieved 7 May 2012. Missing or empty |title= (help)
  57. ↑ "NPOI - Navy Prototype Optical Interferometer". .lowell.edu. 2006-04-13. Retrieved 2013-11-14.
  58. ↑ (PDF) https://web.archive.org/20120222023621/http://ad.usno.navy.mil/edboard/090925.pdf. Archived from the original (PDF) on 22 February 2012. Retrieved 18 February 2016. Missing or empty |title= (help)
  59. ↑ Plans for utilizing the Keck Outrigger Telescopes at NPOI | Publications. SPIE. Retrieved 18 October 2011.
  60. ↑ "Ground-based optical interferometry". Scholarpedia. 2012-02-23. Retrieved 2013-11-14.
  61. ↑ Andreas Quirrenbach. "Optical Interferometry" (PDF). Frank.harvard.edu. Retrieved 2013-11-14.
  62. ↑ Large-Angle Astrometry at the Navy Prototype Optical Interferometer (NPOI). Adsabs.harvard.edu. Retrieved 18 October 2011.
  63. ↑ https://web.archive.org/20140808061310/http://www.lowell.edu/npoi/publications/bibliography.php. Archived from the original on 8 August 2014. Retrieved 18 February 2016. Missing or empty |title= (help)
  64. ↑ "A Survey of Geosynchronous Satellite Glints" (PDF). Amostech.com. Retrieved 2013-11-14.
  65. ↑ "Satellite Imaging and Characterization with Optical Interferometry" (PDF). Amostech.com. Retrieved 2013-11-14.
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