Large Synoptic Survey Telescope

:"LSST" redirects here. For the Lincolnshire School of Science and Technology, see The Priory LSST."Infobox Telescope
bgcolour=
name=Large Synoptic Survey Telescope


caption=
organization=LSST Corporation
location=El Peñón, Chile
coords=coord|30|14|28.5|S|70|44|50.8|W|display=inline,title|region:CL-CO_type:landmark_source:UTM(19J,6653188.8N,331858.7E)Citation |contribution=LSST Summit Testing and Facility Design |title=211th Meeting of the American Astronomical Society |publisher=AAS |place=Austin, TX |author1=J. Sebag |author2=al. |date=January 11, 2008 |url=http://www.lsst.org/Meetings/AAS/2008/JanPosters/originals/sebag_137.16.pdf |accessdate=2008-01-28 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. [http://www.pma-map.com/en/map/newsletters/pdf/v3n10.pdf] ]
altitude=2,657 m (base of dome)
weather=
wavelength=320–1060 nmCitation |title=LSST Basic Configuration |url=http://www.lssto.org/Science/lsst_baseline.shtml |accessdate=2008-01-28 |publisher=LSST Corporation]
built=
first_light=Fall 2015
website=http://www.lsst.org/
style=Paul-Baker/wbrMersenne-Schmidt wide-angle [Citation |journal=Monthly Notices of the Royal Astronomical Society |issn=0035-8711 |date=October 1, 1984 |volume=210 |issue=3 |pages=597–609 |title=The Mersenne-Schmidt: A three-mirror survey telescope |last=Willstrop |first=R. V. |url=http://adsabs.harvard.edu/abs/1984MNRAS.210..597W |accessdate=2008-01-23]
diameter=8.4m
angular_resolution=0.7″ median seeing limit
0.2″ pixel size
area=35 m²
focal_length=9.9m
mounting=altitude/azimuth
dome=

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.Citation |title=The LSST Project at BNL |author=P. O'Connor |date=April 17, 2007 |url=http://www.bnl.gov/npp/docs/doehep07/oconnor_LSST%2004-17-2007.pdf |page=14 |accessdate=2008-01-28]

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. [ [http://www.lsst.org/News/site_selection.shtml LSST Observatory - News & Events ] ]

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.

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 meters 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. (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. [ [http://www.as.arizona.edu:8080/Astro/1105487560/index_html Steward Observatory Mirror Lab Awarded Contract for Large Synoptic Survey Telescope Mirror ] ] Construction of the mold began in November 2007 at the University of Arizona's Steward Observatory Mirror Lab, [ [http://www.lsst.org/Images/m1m3construction.shtml LSST Observatory - Site Photos ] ] mirror casting was begun in March 2008 [ [http://www.lsst.org/News/highfire_event.shtml LSST High Fire Event] ] , and the mirror blank was declared "perfect" at the beginning of September 2008. [Citation |url=http://www.lsst.org/News/LSSTC_08.shtml |publisher=LSST Corporation |title=Giant Furnace Opens to Reveal 'Perfect' LSST Mirror Blank |date=2009-09-02 |accessdate=2008-09-03] A 3.2 gigapixel prime focus [The camera is actually at the tertiary focus, not the prime focus, but being located at a "trapped focus" in front of the primary mirror, the associated technical problems are similar to those of a conventional prime-focus survey camera.] digital camera will take a 15-second exposure every 20 seconds.

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. [cite news
url=http://www.nytimes.com/2008/01/05/science/space/05scope.html?ex=1357189200&en=b96008fcade4d4f0&ei=5088&partner=rssnyt&emc=rss
title=Donors Bring Big Telescope a Step Closer
author=Dennis Overbye
date=January 3 2008
publisher=The New York Times
accessdate=2008-01-03]

Scientific goals

Particular scientific goals of the LSST include:
* Measuring weak gravitational lensing in the deep sky to detect signatures of dark energy and dark matter.
* Mapping small objects in the solar system, particularly near-Earth asteroids and Kuiper belt objects.
* Detecting transient optical events such as novae and supernovae.
* Mapping the Milky Way.

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 [Citation |url=http://www.theregister.co.uk/2008/10/03/lsst_jeff_kantor/print.html |title=Mapping the universe at 30 Terabytes a night: Jeff Kantor, on building and managing a 150 Petabyte database |author=Matt Stephens |publisher=The Register |date=2008-10-03 |accessdate=2008-10-03] ) will be made available by Google as an up-to-date interactive night-sky map. [ [http://uanews.org/node/12956 Google Joins Large Synoptic Survey Telescope (LSST) Project] ]

ee also

* Pan-STARRS
* List of largest optical reflecting telescopes

References

External links

* [http://www.lsst.org/lsst_home.shtml Official home page]
* [http://www.lsst.org/Science/docs.shtml LSST reports and documentation]
* [http://www.deccanherald.com/deccanherald/Mar142005/snt8.asp Science & Technology brief]
* [http://www.newscientistspace.com/article/dn9200-unique-widefield-telescope-will-make-sky-movies.html New Scientist SPACE Article]
* [http://www-group.slac.stanford.edu/kipac/lsst_tutorials_for%20_experimental_particle_physicists.htm LSST Tutorials for Experimental Particle Physicists] is a detailed explanation of LSST's design (as of February 2006) and weak lensing science goals that does not assume a lot of astronomy background.
* [http://video.google.com/videoplay?docid=4364162621957872851 The New Digital Sky] is a video of a July 25, 2006 presentation at Google about the LSST, particularly the data management issues.
* [http://www.huliq.com/5028/google-joins-large-synoptic-survey-telescope-project HULIQ Google participation announcement]
*Citation |title=LSST: From Science Drivers to Reference Design and Anticipated Data Products (v1.0) |url=http://www.lsst.org/overview/overview_v1.0.pdf |author=Ž. Ivezić et al. |date=2008-05-15 |id=arxiv|astro-ph|0805.2366 |accessdate=2008-06-01, this is a comprehensive overview of the LSST.