Vera C. Rubin Observatory
- "LSST" redirects here. For the Lincolnshire School of Science and Technology, see The Priory LSST.
 | |
| Alternative names | LSST |
|---|---|
| Named after | Vera Rubin  |
| Location(s) | Elqui Province, Coquimbo Region, Chile |
| Coordinates | 30°14′39.6″S 70°44′57.8″W / 30.244333°S 70.749389°W[1][2] |
| Organization | LSST Corporation |
| Observatory code | X05 |
| Altitude | 2,662.75 m (top of pier)[3] |
| Wavelength | 320–1060 nm[4] |
| First light | Fall 2015[4] |
| Telescope style | Paul-Baker/ |
| Diameter | 8.360 m (5.116 m inner)[6] |
| Secondary diameter | 3.420 m (1.800 m inner)[6] |
| Tertiary diameter | 5.016 m (1.100 m inner)[6] |
| Angular resolution | 0.7″ median seeing limit 0.2″ pixel size[4] |
| Collecting area | 35 m²[4] |
| Focal length | 10.31 m (f/1.23) overall 9.9175 m (f/1.186) primary |
| Mounting | altitude/azimuth |
| Website | http://www.lsst.org/ |
  Location of Large Synoptic Survey Telescope | |
 Related media on Commons | |
The Large Synoptic Survey Telescope (LSST) is a planned wide-field "survey" reflecting telescope that will photograph the entire available sky every few nights[7]. The LSST is currently in its design and development phase and will achieve engineering first light four years after construction starts. Full science operations for the ten-year survey will begin two years after that, toward the end of the decade.
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.[8]
Overview
The LSST design 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.[4]
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.[4] (Multiplying this by the field of view produces an etendue of 336 m²degree²; the actual figure is reduced by vignetting.)
The primary and tertiary mirrors are being constructed as a single piece of glass, the "M1M3 monolith".
A 3.2 gigapixel prime focus[9] digital camera will take a 15-second exposure every 20 seconds.[4]
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.[10][11] Initial computer requirements are estimated at 100 teraflops of computing power and 15 petabytes of storage, rising as the project collects data.[12]
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[10]) will be made available by Google as an up-to-date interactive night-sky map.[13]
Construction progress
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.[14] $7.5 million is included in the U.S. president's FY2013 NSF budget request.[15] The Department of Energy is expected to fund construction of the digital camera component by the SLAC National Accelerator Laboratory, as part of its mission to understand dark energy.[16]
The LSST was greatly encouraged by its selection as the highest-priority ground-based instrument in the 2010 Astronomy and Astrophysics Decadal Survey.[17]
Construction of the primary mirror, the most critical and time-consuming part of a large telescope's construction, is already well underway. The M1M3 monolith is being constructed at the University of Arizona's Steward Observatory Mirror Lab.[18] Construction of the mold began in November 2007,[19] mirror casting was begun in March 2008,[20] and the mirror blank was declared "perfect" at the beginning of September 2008.[21] As of January 2011[ref], both M1 and M3 figures have been generated, and fine grinding is pending.[2]
The secondary mirror blank has been constructed and coarse-ground to within 40 μm of the desired shape. It is in storage awaiting funding to complete it.[2]
Site excavation began in earnest March 8, 2011,[22] and a construction progress website maintains two webcams showing live construction progress.
As of January 2012[update],[23] the LSST site has been leveled, the primary mirror has been ground, and is awaiting polishing while the tertiary mirror is fine-ground. The M1M3 monolith is expected to be completed in late 2012. The design of the telescope buildings (dome, maintenance workshop, control room and utilities) is almost complete, and numerous telescope subsystems are having their designs fine-tuned. In particular the mirror support system, stray light baffles, wind screen, and calibration screen have been significantly improved.
See also
References
- ^ Charles F. Claver; et al. (2007-03-19), LSST Reference Design (PDF), LSST Corporation, pp. 64–65, retrieved 2008-12-10
{{citation}}: Explicit use of et al. in:|author2=(help) The map on p. 64 shows the Universal Transverse Mercator location of the centre of the telescope pier at approximately 6653188.9 N, 331859.5 E, in zone 19J. However, those UTM coordinates appear to be using the PSAD56 (La Canoa) datum, as other assumptions do not lead to a peak. This is apparently widely used in South American UTM grids. The coordinates above translate to WGS84 30°14′39.6″S, 70°44′57.8″W. - ^ a b c Victor Krabbendam; et al. (2011-01-11). "LSST Telescope and Optics Status" (PDF). American Astronomical Society 217th Meeting (poster). Seattle, Washington. Retrieved 2011-01-16.
{{cite conference}}: Explicit use of et al. in:|author2=(help); Unknown parameter|booktitle=ignored (|book-title=suggested) (help) This updated plan shows the revised telescope centre at 6653188.0 N, 331859.1 E (PSAD56 datum). This is the same WGS84 location to the resolution shown. - ^ LSST Summit Facilities, 2009-08-14, retrieved 2009-08-21
- ^ a b c d e f g LSST Basic Configuration, LSST Corporation, retrieved 2008-01-28
- ^ 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, Bibcode:1984MNRAS.210..597W, ISSN 0035-8711, retrieved 2008-01-23
- ^ a b c Gressler, William (June 2, 2009), LSST Optical Design Summary (PDF), LSE-11, retrieved 2011-03-01
- ^ LSST Observatory - FAQ
- ^ LSST Observatory - News & Events
- ^ 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.
- ^ a b Matt Stephens (2008-10-03), Mapping the universe at 30 Terabytes a night: Jeff Kantor, on building and managing a 150 Petabyte database, The Register, retrieved 2008-10-03
- ^ Matt Stephens (2010-11-26), Petabyte-chomping big sky telescope sucks down baby code, The Register, retrieved 2011-01-16
- ^ Boon, Miriam (2010-10-18), "Astronomical Computing", Symmetry Breaking, retrieved 2010-10-26
- ^ Google Joins Large Synoptic Survey Telescope (LSST) Project
- ^ Dennis Overbye (January 3, 2008). "Donors Bring Big Telescope a Step Closer". The New York Times. Retrieved 2008-01-03.
- ^ "LSST Project Office Update". March 2012. Retrieved 2012-04-07.
- ^ "World's largest digital camera gets green light". 2011-11-08.
{{cite web}}: Text "accessdate-2012-04-07" ignored (help)/ - ^ Large Synoptic Survey Telescope gets Top Ranking, "a Treasure Trove of Discovery", LSST Corporation, 2010-08-16, retrieved 2011-01-16
- ^ Steward Observatory Mirror Lab Awarded Contract for Large Synoptic Survey Telescope Mirror
- ^ LSST Observatory - Site Photos
- ^ LSST High Fire Event
- ^ Giant Furnace Opens to Reveal 'Perfect' LSST Mirror Blank (PDF), LSST Corporation, 2009-09-02, retrieved 2011-01-16
- ^ Cerro Pachón First Blast, LSST Corporation, March 8, 2011, retrieved 2011-04-23,
'First Blast', detonated on the El Peñón summit March 8th at 8:56:00 (MST) in preparation for the LSST
- ^ Victor Krabbendam; et al. (2012-01-09). "Developments in Telescope and Site" (PDF). American Astronomical Society 219th Meeting (poster). Austin, Texas. Retrieved 2012-01-16.
{{cite conference}}: Explicit use of et al. in:|author2=(help); Unknown parameter|booktitle=ignored (|book-title=suggested) (help)
External links
- Official home page
- LSST reports and documentation
- Science & Technology brief
- New Scientist SPACE Article
- 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.
- The New Digital Sky is a video of a July 25, 2006 presentation at Google about the LSST, particularly the data management issues.
- HULIQ Google participation announcement
- Ž. Ivezić; et al. (2008-05-15), LSST: From Science Drivers to Reference Design and Anticipated Data Products (v1.0) (PDF), vol. 0805, p. 2366, arXiv:0805.2366, Bibcode:2008arXiv0805.2366I, retrieved 2011-01-16
{{citation}}: Explicit use of et al. in:|author=(help), this is a comprehensive overview of the LSST. - LSST Science Collaborations; Abell, Paul A.; Allison, Julius; Anderson, Scott F.; Andrew, John R.; Angel, J. Roger P.; Armus, Lee; Arnett, David; Asztalos, S. J. (2009-10-16), LSST Science Book, Version 2.0, vol. 0912, p. 201, arXiv:0912.0201, Bibcode:2009arXiv0912.0201L, retrieved 2011-01-16, an updated and expanded overview.