Large Synoptic Survey Telescope

Ranked as the top ground-based national priority for the field for the current decade, LSST is currently under construction in Chile. The U.S. Department of Energy’s SLAC National Accelerator Laboratory is leading the construction of the LSST camera – the largest digital camera ever built for astronomy. SLAC Professor Steven M. Kahn is the overall Director of the LSST project, and SLAC personnel are also participating in the data management. The National Science Foundation is the lead agency for construction of the LSST. Additional financial support comes from the Department of Energy and private funding raised by the LSST Corporation.

Learn More About the LSST Camera

LSST Science Goals

What Will LSST Look At?

The LSST will survey the entire visible southern sky every few days for a decade. Its vast public archive of data will dramatically advance our knowledge of the dark energy and dark matter that make up 95 percent of the universe, as well as galaxy formation and potentially hazardous asteroids.

Dark Matter

Gravitational lensing is our best tool for finding dark matter. LSST's power and large field of view will enable us to see weaker lenses, which are more common.

Current Composition of the Universe

Current observations indicate the ordinary matter that we see all around us makes up only 5 percent of our universe. The data collected by the LSST will enhance our understanding of the rest of the universe – dark matter and dark energy.

Dark Energy

LSST's 18,000-square-degree coverage of billions of galaxies has the power to test differences in fundamental properties of space and time itself in different directions.

The Solar System

The LSST will undertake a thorough exploration of our solar system with two goals in mind: learning how it originally formed, and protecting Earth from hazardous, near-flying asteroids.

The Milky Way

Individual stars in the Milky Way and the galaxies nearby can be resolved by the LSST. These stars then provide a fossil record—a Rosetta Stone—that can be decoded to determine how these galaxies formed.

The Changing Sky

The LSST will scan the sky repeatedly to great depth, enabling it to both discover new, distant transient events and to study variable objects throughout our universe.

Nuts and Bolts

The LSST camera project is funded by the DOE and managed by SLAC. Construction began in 2015 in SLAC's new clean room, as the lab is leading the camera's design and fabrication. The 3.2-gigapixel prime focus digital camera will take a 15-second exposure every 20 seconds, which requires very precise focusing due to the rapid repointing. It will produce data of extremely high quality with minimal downtime and maintenance.

Camera Overview

About the size of a small SUV, the LSST camera is the largest camera ever constructed for astronomy. It is a large-aperture, wide-field optical camera that is capable of viewing light from the near ultraviolet to near infrared wavelengths.

Length	12.25 ft (3.73 m)
Height	5.5 ft (1.65 m)
Weight	6200 lbs (2800 kg)
Pixel Count	3200 megapixel
Wavelength Range	320–1050 nm

Note: 1 nm (nanometer) = 10^-9 m or one-billionth of a meter

Focal Plane

The focal plane is the heart of the camera, where light from billions of galaxies comes to a focus. It consists of 189 charge-coupled device (CCD) sensors, arranged in a total of 21 3-by-3 square arrays mounted on platforms called rafts. The system is cooled to about -100 °C to minimize noise.

The 64-cm-wide focal plane corresponds to a 3.5-degree field of view, which means the camera can capture more than 40 times the area of the full moon in the sky with each exposure.

Filter Changer

The camera also contains a carousel that holds five on-board filters. Each of the filters can be individually swapped out in under two minutes and up to four times a night with the double-rail auto changer. The system also integrates with a manual load-lock changer to allow for a swap-out of a sixth filter.

The optimized wavelength range for the LSST camera is 320–1050 nm (near ultraviolet to near infrared). This range is divided into six spectral bands labeled u-g-r-i-z-y, each associated with one of the filters. For example, an infrared, or "i" filter might be used to observe sources obscured by dust, since infrared wavelengths can pass through the dust.

More Technical Info About the Camera

LSST Stats

Fun Facts & Key Numbers

The concept behind the LSST project is remarkably simple: conduct a deep survey over an enormous area of sky; do it with a frequency that enables images of every part of the visible sky to be obtained every few nights; and continue in this mode for 10 years to achieve astronomical catalogs thousands of times larger than ever previously compiled – the first time a telescope will catalog more galaxies than there are people on Earth.

Foot primary mirror

3.2

Gigapixel detector

Terabytes of data per night

Billion stars & galaxies

Year survey of the sky

Funding & Collaboration

Financial support for LSST comes from the National Science Foundation (NSF) through Cooperative Agreement No. 1258333, the Department of Energy (DOE) Office of Science under Contract No. DE-AC02-76SF00515, and private funding raised by the LSST Corporation. The NSF-funded LSST Project Office for construction was established as an operating center under management of the Association of Universities for Research in Astronomy (AURA). The DOE-funded effort to build the LSST camera is managed by the SLAC National Accelerator Laboratory (SLAC).