Giant Magellan Telescope

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Giant Magellan Telescope
Artwork of Giant Magellan Telescope
Organization GMT Consortium
Location Las Campanas Observatory, Chile
Coordinates 29°01.7′S 70°41.15′W / -29.0283, -70.68583Coordinates: 29°01.7′S 70°41.15′W / -29.0283, -70.68583
Altitude 2,516 m[1][2]
Wavelength 320–25000 nm[3]
Built Awaiting funding
Telescope style Gregorian
Diameter 25.448 m[4]
Angular resolution 0.21–0.3″ at 500 nm[3]
Collecting area 368 m²[4]
Focal length 18.000 m (M1)
202.745 m (M1+M2)[4]
Mounting altitude/azimuth
Website http://www.gmto.org/

The Giant Magellan Telescope (GMT) is a ground-based telescope planned for completion in 2016. It will consist of seven, 8.4 m (27.6 ft) "primary" mirrors,[5] with the resolving power of a 24.5 m (80.4 ft) primary mirror.[6] The telescope is expected to have over four times the light-gathering ability of existing instruments.

Contents

[edit] Planned site

The confirmed location of the telescope will be the Las Campanas Observatory,[7] which is also the site of the Magellan telescopes, some 115 km (71 mi) north-northeast of La Serena, Chile. Much as for previous notable telescopes, the site has been chosen as the new instrument's location because of its clear weather throughout most of the year.[8] Moreover, due to the sparsity of population centers and other favorable geographical conditions, the night sky in most of the surrounding Atacama Desert region is not only free from atmospheric pollution, but in addition it is probably one of the places least affected by light pollution, making the area one of the best spots on Earth for long-term astronomical observation.

[edit] Design peculiarities

The telescope is unique in that it will use seven mirror segments, each 8.4 m (27.6 ft) in diameter. These segments will then be arranged to form a single optical surface. The challenge in this is that the surface of the outer six mirror segments is not radially symmetrical (i.e. they are off-axis), necessitating a slight modification of the usual polishing procedure. Although the outer six mirrors will individually be off-axis, the design calls for the mirrors to be arranged so that the reflecting surface of all seven mirrors as a whole is on-axis, with one mirror in the center and the other six arranged symmetrical around the center, giving a focal plane on-axis with the entire assembly. The intention is to build seven identical off-axis mirrors, so that a spare is available to substitute for a segment being recoated, a 1–2 week (per segment) process required every 1–2 years.[9]

The mirrors are being constructed by the Steward Observatory at the University of Arizona, at a laboratory beneath the university's football stadium. The casting of the first mirror was completed on November 3, 2005, but the time-consuming shaping and polishing remains.

[edit] Organizations

The following is a list of the members of a consortium developing the telescope.[10]

  1. Observatories of the Carnegie Institution of Washington (OCIW)
  2. Harvard University
  3. Massachusetts Institute of Technology
  4. Smithsonian Astrophysical Observatory
  5. Texas A&M University
  6. University of Arizona
  7. University of Michigan
  8. University of Texas at Austin
  9. Australian National University

[edit] See also

[edit] References

  1. ^ José Terán U.; Daniel H. Neff & Matt Johns (2006-05-29), “Conceptual design study of the GMT enclosure”, SPIE 6267: Symposium on Astronomical Telescopes and Instrumentation, Orlando, FL: SPIE, p. 2, <http://www.gmto.org/reportspresentations/GMT-ID-01453-GMTEnclosure2006.pdf>. Retrieved on 31 March 2008 
  2. ^ Joanna Thomas-Osip (2007-03-20), “The Seeing and Turbulence Profile at Las Campanas Observatory: GMT Site Testing Progress Report”, Syposium on Seeing, Kona, HI: AAS, p. 3, <http://weather.hawaii.edu/symposium/program/presentations/ses1.1615.Joanna_Thomas-Osip.pdf>. Retrieved on 31 March 2008 
  3. ^ a b Giant Magellan Telescope Science Requirements, GMT Consortium, <http://www.gmto.org/sciencecase/GMT-ID-01405-GMT_Science_Requirements.pdf>. Retrieved on 31 March 2008 
  4. ^ a b c “Chapter 6: Optics”, GMT Conceptual Design Report, GMT Consortium, p. 6-3, <http://www.gmto.org/codrfolder/GMT-ID-01467-Chapter_6_Optics.pdf>. Retrieved on 2 April 2008 
  5. ^ Giant Magellan Telescope Partner Institutions. GMT Consortium. Retrieved on 2007-04-03.
  6. ^ Maggie McKee. "Giant telescope in race to become world's largest", New Scientist, 2007-10-04. Retrieved on 2007-10-07. 
  7. ^ Giant Magellan telescope site selected. Carnegie Institution. Retrieved on 2007-10-05.
  8. ^ Robinson, Travis. "Eye on the sky", The Battalion, 2007-04-03. Retrieved on 2007-04-03. 
  9. ^ (February 2006) "Telescope Structure", GMT Conceptual Design Report. Retrieved on 2007-10-07.  Section 7.4.5, page 7-17.
  10. ^ Giant Magellan Telescope Partner Institutions. GMT Consortium. Retrieved on 2007-04-03.

[edit] External links