McDonald Observatory

The McDonald Observatory is an astronomical observatory located near the unincorporated community of Fort Davis in Jeff Davis County, Texas, United States. The facility is located on Mount Locke in the Davis Mountains of West Texas, with additional facilities on Mount Fowlkes, approximately 1.3 kilometers (0.81 mi) to the northeast.[1] The observatory is part of the University of Texas at Austin. It is an organized research unit of the College of Natural Sciences.

McDonald Observatory
McDonald Observatory showing Mt. Fowlkes (left) and Mt. Locke (right) as seen from the northwest on Texas State Highway 118.
Named afterWilliam Johnson McDonald 
OrganizationUniversity of Texas at Austin 
Observatory code 711 
LocationJeff Davis County, Texas
Coordinates30°40′17″N 104°01′19″W
Altitude2,070 m (6,790 ft)
Established1933 
Websitemcdonaldobservatory.org
TelescopesFrank N. Bash Visitors Center
Harlan J. Smith Telescope
Hobby–Eberly Telescope
Otto Struve Telescope 
Location of McDonald Observatory
Related media on Wikimedia Commons

The observatory produces StarDate, a daily syndicated radio program consisting of short segments related to astronomy that airs on both National Public Radio and commercial radio stations — about 400 affiliates in all.

History
McDonald Observatory

The McDonald Observatory was originally endowed by the Texas banker William Johnson McDonald (1844–1926), who left about $1 million - the bulk of his fortune - to the University of Texas to endow an astronomical observatory. The provision of the will was challenged by McDonald's relatives, but after a long legal fight, the University received about $800,000 from the estate and construction began at Mt. Locke. The then-unnamed Otto Struve Telescope was dedicated on May 5, 1939,[2] and at that time was the second largest telescope in the world. McDonald Observatory was operated under contract by the University of Chicago until the 1960s, when control was transferred to the University of Texas at Austin under the direction of Harlan J. Smith.[3]

Research today at the McDonald Observatory encompasses a wide variety of topics and projects, including planetary systems, stars and stellar spectroscopy, the interstellar medium, extragalactic astronomy, and theoretical astronomy.[4]

Directors[3]

Observatory
Dome of the 10 m Hobby-Eberly Telescope. It houses one of the largest optical telescopes in the world.

The McDonald Observatory is equipped with a wide range of instrumentation for imaging and spectroscopy in the optical and infrared spectra, and operates the first lunar laser ranging station. It works closely with the astronomy department of the University of Texas at Austin while maintaining administrative autonomy. The high and dry peaks of the Davis Mountains make for some of the darkest and clearest night skies in the region and provide excellent conditions for astronomical research.

Electric motors and position sensors at the Otto Struve Telescope at the McDonald Observatory, Texas.

The Otto Struve Telescope, dedicated in 1939, was the first large telescope built at the observatory.[8][9] It is located on Mt. Locke at an altitude of 2,070 m (6,790 ft). The summit of Mt. Locke, accessed by Spur 78, is the highest point on Texas highways.[10] The Harlan J. Smith Telescope, also on Mt. Locke, was completed in 1968.[11][12]

The Hobby-Eberly Telescope (HET), dedicated in late 1997, is located on the summit of Mt. Fowlkes at 2,030 m (6,660 ft) above sea level.[13] It is operated jointly by the University of Texas at Austin, Pennsylvania State University, Ludwig Maximilian University of Munich, and Georg-August University of Göttingen.[14] As of 2019, after upgrades the HET is tied with the Keck Telescopes as the second or third largest telescope in the world. However, its cost was about 20% that of other similarly-sized telescopes in use today due to its optimization for spectroscopy.

Telescopes
Domes of the 2.1 m Otto Struve Telescope (left) and 2.7 m Harlan J. Smith Telescope (right).

Currently, the observatory operates four research telescopes at its West Texas site:

A 0.9 m (36 in) telescope, formerly used for research, is now used for visitor programs.[17][18]

Tenant telescopes

The two peaks also host a number of other instruments:

Former telescopes
  • The 4.9 m (16 ft) Millimeter Wave Observatory (MWO) radio telescope operated on Mt. Locke until 1988.[23] MWO was a joint project between the UT Department of Astronomy and the Department of Electrical Engineering. The site of the dish antenna is now occupied by the BLOOMhouse, the UT School of Architecture's entry in the 2007 Solar Decathlon, which is now used for staff housing.[24]

Climate

The observatory experiences a semi-arid climate (Köppen BSk) with cool, dry winters and hot, wetter summers.

Climate data for Mount Locke, Texas (Jan 1, 1935–Mar 31, 2013)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 80
(27)		 79
(26)		 88
(31)		 94
(34)		 96
(36)		 104
(40)		 100
(38)		 104
(40)		 96
(36)		 94
(34)		 82
(28)		 80
(27)		 104
(40)
Average high °F (°C) 53.5
(11.9)		 56.9
(13.8)		 63.7
(17.6)		 71.4
(21.9)		 78.6
(25.9)		 84.5
(29.2)		 82.7
(28.2)		 81.3
(27.4)		 76.6
(24.8)		 70.5
(21.4)		 61.2
(16.2)		 54.4
(12.4)		 69.6
(20.9)
Daily mean °F (°C) 42.7
(5.9)		 45.4
(7.4)		 51.0
(10.6)		 58.3
(14.6)		 65.5
(18.6)		 71.4
(21.9)		 70.8
(21.6)		 69.8
(21.0)		 65.5
(18.6)		 59.3
(15.2)		 50.0
(10.0)		 44.0
(6.7)		 57.8
(14.3)
Average low °F (°C) 32.0
(0.0)		 33.9
(1.1)		 38.2
(3.4)		 45.2
(7.3)		 52.4
(11.3)		 58.2
(14.6)		 58.9
(14.9)		 58.4
(14.7)		 54.4
(12.4)		 48.0
(8.9)		 38.7
(3.7)		 33.6
(0.9)		 46.0
(7.8)
Record low °F (°C) −10
(−23)		 −6
(−21)		 4
(−16)		 11
(−12)		 26
(−3)		 36
(2)		 40
(4)		 40
(4)		 29
(−2)		 13
(−11)		 8
(−13)		 −2
(−19)		 −10
(−23)
Average precipitation inches (mm) 0.68
(17)		 0.49
(12)		 0.40
(10)		 0.50
(13)		 1.63
(41)		 2.49
(63)		 3.83
(97)		 3.69
(94)		 2.95
(75)		 1.61
(41)		 0.61
(15)		 0.60
(15)		 19.46
(494)
Average snowfall inches (cm) 1.9
(4.8)		 0.8
(2.0)		 0.2
(0.51)		 0.1
(0.25)		 0.0
(0.0)		 0.0
(0.0)		 0.0
(0.0)		 0.0
(0.0)		 0.0
(0.0)		 0.1
(0.25)		 0.4
(1.0)		 1.2
(3.0)		 4.7
(12)
Average precipitation days (≥ 0.001) 3.75 3.13 2.62 2.77 5.93 8.75 12.00 11.56 9.32 5.91 2.94 3.29 71.45
Source: Western Regional Climate Center, Desert Research Institute[26]

Visiting
Inside the dome of the Harlan J. Smith telescope during a guided tour

The Frank N. Bash Visitors Center, located between Mt. Locke and Mt. Fowlkes, includes a café, gift shop, and interactive exhibit hall. The Visitors Center conducts daily live solar viewings in a large theater and tours of the observatory's largest telescopes. It also hosts evening star parties, every Tuesday, Friday, and Saturday evening which allow visitors to look through numerous telescopes of various sizes in the Telescope Park, including the wheelchair accessible Wren Marcario Accessible Telescope (a Pfund Telescope), and enjoy an indoor program.[27]

Special viewing nights, during which visitors can stay on-site (not required for the programs) and view directly through eyepieces on the 0.9 m, Struve (2.1m), or Smith (2.7m) telescopes, are held on a reservation-only basis. Although not available for several years, as of June 2013, the 2.1m has returned to occasional public access.[28]

  • Entrance to the observatory
  • Frank N. Bash Visitors Center
  • McDonald Observatory's Visitor Center's Sun Dial
  • Harlan J. Smith Telescope preparing for observations
  • Texas Historical Marker
  • Texas Highway Marker at McDonald Observatory

See also

References
  1. "About | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  2. The Film & Video Archive of the McDonald Observatory. "Franklin Mountains and Dedication Ceremony (1939)". Texas Archive of the Moving Image.
  3. Evans, David S., University of Texas at Austin McDonald Observatory, Texas State Historical Association
  4. "UT Astronomy - Research". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  5. McDonald Observatory Visitors Center Named for Former Director Dr. Frank N. Bash, The University of Texas McDonald Observatory, 2006-07-17
  6. American Astronomical Society Confers Highest Honor on McDonald Observatory Director David Lambert, The University of Texas McDonald Observatory, 2007-02-05
  7. Leading Astronomer Taft Armandroff Appointed New Director of McDonald Observatory, The University of Texas McDonald Observatory, 2014-01-14
  8. "McDonald Observatory - 2.1-m Telescope". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  9. "The Otto Struve Telescope | What Are Astronomers Doing? | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  10. Dindinger, Peter. (25 August 2009). "The Highest Point on Texas Highways". Retrieved 2012-01-10.
  11. "McDonald Observatory - 2.7 m Telescope". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  12. "The Harlan J. Smith Telescope | What Are Astronomers Doing? | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  13. "Hobby-Eberly Telescope". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  14. "The Hobby-Eberly Telescope | What Are Astronomers Doing? | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  15. "UT Astronomy - 0.8 m Telescope". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  16. "0.8-meter Telescope | What Are Astronomers Doing? | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  17. "UT Astronomy - 0.9 m Telescope". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  18. "0.9-meter telescope | What Are Astronomers Doing? | McDonald Observatory". McDonald Observatory. Retrieved 2012-01-10.
  19. "Welcome to MONET / Astronomie & Internet". University of Göttingen.
  20. "McDonald Observatory - Laser Ranging System". University of Texas at Austin Astronomy Program. Retrieved 2012-01-10.
  21. "BU Imaging Science - The Boston University 20-inch Telescope at McDonald Observatory". Boston University Center For Space Physics. Retrieved 2012-01-10.
  22. "ROTSE Home Page". Robotic Optical Transient Search Experiment. Retrieved 2012-01-10.
  23. "University of Texas at Austin, Department of Astronomy, Austin, Texas 78712-1083, McDonald Observatory, Fort Davis, Texas 79734. Report for the period 1 Sep 1988 - 31 Aug 1989". Bulletin of the Astronomical Society. 22: 620. 1990. Bibcode:1990BAAS...22R.620.
  24. Johnson, Rebecca (2008-05-01). "McDonald Observatory gets Solar BLOOMhouse « Know". Retrieved 2012-01-30.
  25. "US COOP Station Map". Western Regional Climate Center, Desert Research Institute. Retrieved May 3, 2015.
  26. "MOUNT LOCKE, TEXAS (416104), Period of Record Monthly Climate Summary". Western Regional Climate Center, Desert Research Institute. Retrieved May 3, 2015.
  27. "McDonald Observatory | Public Programs, Star Parties, Tours and Special Viewing Night". McDonald Observatory. Archived from the original on 2011-12-17. Retrieved 2012-01-10.
  28. "McDonald Observatory | Public Programs: Special Viewing Night". McDonald Observatory. Archived from the original on 2011-12-09. Retrieved 2012-01-10.
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