Large Synoptic Survey Telescope

The Large Synoptic Survey Telescope (LSST) is a wide-field survey reflecting telescope with an 8.4-meter primary mirror, currently under construction, that will photograph the entire available sky every few nights. The word synoptic is derived from the Greek words σύν (syn 'together') and ὄψις (opsis 'view'), and describes observations that give a broad view of a subject at a particular time.The Large-aperture Synoptic Survey Telescope (LSST) is a 6.5-m-class optical telescope designed to survey the visible sky every week down to a much fainter level than that reached by existing surveys. It will catalog 90 percent of the near-Earth objects larger than 300 m and assess the threat they pose to life on Earth. It will find some 10,000 primitive objects in the Kuiper Belt, which contains a fossil record of the formation of the solar system. It will also contribute to the study of the structure of the universe by observing thousands of supernovae, both nearby and at large redshift, and by measuring the distribution of dark matter through gravitational lensing. All the data will be available through the National Virtual Observatory (see below under “Small Initiatives”), providing access for astronomers and the public to very deep images of the changing night sky.Rendering of the LSST camera.Color-coded cutaway drawing of the LSST camera.Exploded view of the optical components of the LSST camera. The Large Synoptic Survey Telescope (LSST) is a wide-field survey reflecting telescope with an 8.4-meter primary mirror, currently under construction, that will photograph the entire available sky every few nights. The word synoptic is derived from the Greek words σύν (syn 'together') and ὄψις (opsis 'view'), and describes observations that give a broad view of a subject at a particular time. The telescope uses a novel 3-mirror design, a variant of three-mirror anastigmat, which allows a compact telescope to deliver sharp images over a very wide 3.5-degree diameter field of view. Images will be recorded by a 3.2-gigapixel CCD imaging camera, the largest digital camera ever constructed. The telescope is located on the El Peñón peak of Cerro Pachón, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes. The LSST Base Facility is located about 100 kilometres (62 mi) away by road, in the town of La Serena. The LSST was proposed in 2001, and construction of the mirror began (with private funds) in 2007. LSST then became the top-ranked large ground-based project in the 2010 Astrophysics Decadal Survey, and the project officially began construction 1 August 2014 when the National Science Foundation (NSF) authorized the FY2014 portion ($27.5 million) of its construction budget. The ceremonial laying of the first stone was performed on 14 April 2015. Site construction began on April 14, 2015, with first light anticipated in 2020, and full operations for a ten-year survey commencing in January 2022. LSST, unlike almost all previous large astronomical observatories, has committed to making all data public as soon as it is taken. LSST is the successor to a long tradition of sky surveys. These started as visually compiled catalogs in the mid 1700s, such as the Messier catalog. This was replaced in the late 1800s by photographic surveys, starting with the Harvard Plate Collection, the National Geographic Society – Palomar Observatory Sky Survey, and others. By about 2000 the first digital surveys, such as the Sloan Digital Sky Survey (SDSS), began to replace the photographic plates of the earlier surveys. LSST evolved from the earlier concept of the Dark Matter Telescope, mentioned as early as 1996. The fifth decadal report, Astronomy and Astrophysics in the New Millennium, was released in 2001, and recommended the 'Large-Aperture Synoptic Survey Telescope' as a major initiative. Even at this early stage the basic design and objectives were set: Early development was funded by a number of small grants, with major contributions in January 2008 by software billionaires Charles Simonyi and Bill Gates of $20- and $10 million respectively. $7.5 million was included in the U.S. President's FY2013 NSF budget request. The Department of Energy is funding construction of the digital camera component by the SLAC National Accelerator Laboratory, as part of its mission to understand dark energy. In the 2010 decadal survey, LSST was ranked as the highest-priority ground-based instrument. NSF funding for the rest of construction was authorized as of 1 August 2014. The camera is separately funded by the Department of Energy. The lead organizations are: