Large Synoptic Survey Telescope

From Wikipedia, the free encyclopedia

This article or section contains information about an expected future scientific facility.
It is likely to contain information of a speculative nature and the content may change as the facility approaches completion.

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 completion in 2013.

The telescope will be located on the El Peñón peak of Cerro Pachón, a 2682 metre high peak in northern Chile, alongside the existing Gemini South, SOAR and Cerro Tololo Inter-American Observatory telescopes.[1]

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. Combined with its large aperture (and thus light-collecting ability), this will give it a spectacularly large etendue of 318 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 primary/tertiary mirror will be built as a monolithic unit by the Mirror Lab at the Steward Observatory in Arizona.[2] A 3.2 billion-pixel prime focus digital camera will take a 15-second exposure every 20 seconds.[3]

The digital camera for the LSST.

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.

Particular scientific goals of the LSST include:

Measuring weak gravitational lensing in the deep sky to detect 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) will be made available by Google as an up-to-date interactive night-sky map ^[1].