Large Synoptic Survey Telescope

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"LSST" redirects here. For the Lincolnshire School of Science and Technology, see The Priory LSST.
Large Synoptic Survey Telescope
Organization LSST Consortium
Location El Peñón, Chile
Coordinates 30°14′28.5″S 70°44′50.8″W / -30.24125, -70.747444Coordinates: 30°14′28.5″S 70°44′50.8″W / -30.24125, -70.747444[1]
Altitude 2,657 m (base of dome)[1]
Wavelength 320–1060 nm[2]
First light Fall 2015[2]
Telescope style Paul-Baker/ Mersenne-Schmidt wide-angle[3]
Diameter 8.4m[2]
Angular resolution 0.7″ median seeing limit
0.2″ pixel size[2]
Collecting area 35 m²[2]
Focal length 9.9m
Mounting altitude/azimuth
Website http://www.lsst.org/
The digital camera for the LSST.
The digital camera for the LSST.

The Large Synoptic Survey Telescope (LSST) is a planned wide-field "survey" reflecting telescope that will photograph the available sky every three nights. Construction should start in 2010 with first light in 2015.[4]

The telescope will be located on the El Peñón peak of Cerro Pachón, a 2682 metre high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.[5]

Contents

[edit] Overview

The LSST is unique among large telescopes (8m-class primary mirrors) in having a very wide field of view: 3.5 degrees in diameter, or 9.6 square degrees. For comparison, both the Sun and Moon, as seen from the Earth, are 0.5 degrees across, or 0.2 square degrees. Combined with its large aperture (and thus light-collecting ability), this will give it a spectacularly large etendue of 319 m²degree².[2]

To achieve this very wide undistorted field of view requires three mirrors, rather than the two used by most existing large telescopes: the primary mirror will be 8.4 metres in diameter, the secondary mirror will be 3.4 metres in diameter, and the tertiary mirror, located in a large hole in the primary, will be 5.0 metres in diameter. The large hole reduces the primary mirror's light collecting area to 35 m², equivalent to a 6.68 m diameter circle.[2] (Multiplying this by the field of view produces an etendue of 336 m²degree²; the actual figure is reduced by vignetting.)

The primary/tertiary mirror will be built as a monolithic unit,[6] and construction of the mold began in November 2007 at the University of Arizona's Steward Observatory Mirror Lab,[7] with casting planned for late March 2008.[8] A 3.2 gigapixel prime focus digital camera will take a 15-second exposure every 20 seconds.[2]

Allowing for maintenance, bad weather, etc., the camera is expected to take over 200,000 pictures (1.28 petabytes uncompressed) per year, far more than can be reviewed by humans. Managing and effectively data mining the enormous output of the telescope is expected to be the most technically difficult part of the project.

In January, 2008 software billionaires Charles Simonyi and Bill Gates pledged $20 million and $10 million respectively to the project. The project continues to seek a National Science Foundation grant of nearly $400 million.[9]

[edit] Scientific goals

Particular scientific goals of the LSST include:

It is also hoped that the vast volume of data produced will lead to additional serendipitous discoveries.

Synoptic is an adjective from the same root as the noun "synopsis", and means "relating to data obtained nearly simultaneously over a large area."

Some of the data from the LSST (up to 30 Terabytes per night) will be made available by Google as an up-to-date interactive night-sky map.[10]

[edit] See also

[edit] References

  1. ^ a b J. Sebag & al. (January 11, 2008), “LSST Summit Testing and Facility Design”, 211th Meeting of the American Astronomical Society, Austin, TX: AAS, <http://www.lsst.org/Meetings/AAS/2008/JanPosters/originals/sebag_137.16.pdf>. Retrieved on 28 January 2008  The map in this document shows the Universal Transverse Mercator location of the centre of the telescope pier at approximately 6653188.8 N, 331858.7 E. The mountain is in zone 19J, and the UTM coordinates were converted using both http://home.hiwaay.net/~taylorc/toolbox/geography/geoutm.html and http://www.ngs.noaa.gov/cgi-bin/utm_getgp.prl although there may be some additional corrections that need to be applied to Chiliean UTM coordinates below the 100m level.[1]
  2. ^ a b c d e f g h LSST Basic Configuration, LSST Corporation, <http://www.lssto.org/Science/lsst_baseline.shtml>. Retrieved on 28 January 2008 
  3. ^ Willstrop, R. V. (October 1, 1984), “The Mersenne-Schmidt: A three-mirror survey telescope”, Monthly Notices of the Royal Astronomical Society 210 (3): 597–609, ISSN 0035-8711, <http://adsabs.harvard.edu/abs/1984MNRAS.210..597W>. Retrieved on 23 January 2008 
  4. ^ P. O'Connor (April 17, 2007), The LSST Project at BNL, p. 14, <http://www.bnl.gov/npp/docs/doehep07/oconnor_LSST%2004-17-2007.pdf>. Retrieved on 28 January 2008 
  5. ^ LSST Observatory - News & Events
  6. ^ Steward Observatory Mirror Lab Awarded Contract for Large Synoptic Survey Telescope Mirror
  7. ^ LSST Observatory - Site Photos
  8. ^ Krabbendam, V.L. & al. (January 2008), LSST Telescope and Site Overview, <http://www.lsst.org/Meetings/AAS/2008/JanPosters/originals/krabbendam_137.15.pdf>. Retrieved on 23 January 2008 
  9. ^ Dennis Overbye. "Donors Bring Big Telescope a Step Closer", The New York Times, January 3, 2008. Retrieved on 2008-01-03. 
  10. ^ Google Joins Large Synoptic Survey Telescope (LSST) Project

[edit] External links