Giant Magellan Telescope

Infobox Telescope
bgcolour=
name=Giant Magellan Telescope


caption=Artwork of Giant Magellan Telescope
organization=GMT Consortium
location=Las Campanas Observatory, Chile
coords=coord|29|01.7|S|70|41.15|W|display=inline,title|region:CL-AT_type:landmark_scale:50000
altitude=2,516 mCitation |publisher=SPIE |title=SPIE 6267: Symposium on Astronomical Telescopes and Instrumentation |url=http://spie.org/x3111.xml |contribution=Conceptual design study of the GMT enclosure |author1=José Terán U. |author2=Daniel H. Neff |author3=Matt Johns |date=2006-05-29 |contribution-url=http://www.gmto.org/reportspresentations/GMT-ID-01453-GMTEnclosure2006.pdf |page=2 |place=Orlando, FL |accessdate=2008-03-31] Citation |contribution=The Seeing and Turbulence Profile at Las Campanas Observatory: GMT Site Testing Progress Report |title=Syposium on Seeing |publisher=AAS |place=Kona, HI |author1=Joanna Thomas-Osip |date=2007-03-20 |contribution-url=http://weather.hawaii.edu/symposium/program/presentations/ses1.1615.Joanna_Thomas-Osip.pdf |url=http://weather.hawaii.edu/symposium/publications/ |page=3 |accessdate=2008-03-31]
weather=
wavelength=320–25000 nmCitation |title=Giant Magellan Telescope Science Requirements |url=http://www.gmto.org/sciencecase/GMT-ID-01405-GMT_Science_Requirements.pdf |accessdate=2008-03-31 |publisher=GMT Consortium]
built="Awaiting funding"
first_light=
website=http://www.gmto.org/
style=Gregorian
diameter=25.448 mCitation |title=GMT Conceptual Design Report |chapter=Chapter 6: Optics |url=http://www.gmto.org/CoDRpublic |chapterurl=http://www.gmto.org/codrfolder/GMT-ID-01467-Chapter_6_Optics.pdf |page=6-3 |accessdate=2008-04-02 |publisher=GMT Consortium]
angular_resolution=0.21–0.3″ at 500 nm
area=368 m²
focal_length=18.000 m (M1)
202.745 m (M1+M2)
mounting=altitude/azimuth
dome=The Giant Magellan Telescope (GMT) is a ground-based telescope planned for completion in 2016. It will consist of seven, convert|8.4|m|ft|1|abbr=on diameter "primary" mirrors,Cite web |url=http://www.gmto.org/newsitems/gmtfoldsphererelease2 |title=Giant Magellan Telescope Partner Institutions |accessdate=2007-04-03 |publisher=GMT Consortium] with the resolving power of a convert|24.5|m|ft|1|abbr=on primary mirror. [cite news |title=Giant telescope in race to become world's largest |date=2007-10-04 |author=Maggie McKee |publisher=New Scientist |url=http://space.newscientist.com/article/dn12742-giant-telescope-in-race-to-become-worlds-largest.html |accessdate=2007-10-07] The telescope is expected to have over four times the light-gathering ability of existing instruments.

Planned site

The confirmed location of the telescope will be the Las Campanas Observatory,cite web |url=http://www.physorg.com/news110712104.html |title=Giant Magellan telescope site selected |publisher=Carnegie Institution |accessdate=2007-10-05] which is also the site of the Magellan telescopes, some convert|115|km|mi|0|abbr=on 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.cite news |url=http://media.www.thebatt.com/media/storage/paper657/news/2007/04/03/News/Eye-On.The.Sky-2819524.shtml |title=Eye on the sky |publisher=The Battalion |accessdate=2007-04-03 |date=2007-04-03 |author=Robinson, Travis] 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.

Design peculiarities

The telescope is unique in that it will use seven mirror segments, each convert|8.4|m|ft|1|abbr=on 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. [cite book |title=GMT Conceptual Design Report |url=http://www.gmto.org/CoDRpublic |chapter=Telescope Structure |chapterurl=http://www.gmto.org/codrfolder/GMT-ID-01468-Chapter_7_Telescope_Structure.pdf/download |year=2006 |month=February |accessdate=2007-10-07 Section 7.4.5, page 7-17.]

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.

Organizations

The following is a list of the members of a consortium developing the telescope.Cite web |url=http://www.gmto.org/ |title=Giant Magellan Telescope Partner Institutions |accessdate=2007-04-03 |publisher=GMT Consortium]

*Observatories of the Carnegie Institution of Washington (OCIW)
* Harvard University
* Massachusetts Institute of Technology
* Smithsonian Astrophysical Observatory
* Texas A&M University
* University of Arizona
* University of Michigan
* University of Texas at Austin
* Australian National University

ee also

*La Serena, Chile
*Magellan telescopes
*Atacama Desert
*Las Campanas Observatory

References

External links

* [http://www.gmto.org/ Giant Magellan Telescope home page]
* [http://web.mit.edu/newsoffice/2004/telescope.html Article from the MIT news office]
* [http://www.newscientist.com/article.ns?id=dn7608 New Scientist article on the telescope]