LSST camera

The LSST camera, being built by SLAC using CCD modules supplied by Teledyne e2v, is said to be the largest ever created for ground-based astronomy. [Image: LSST Project/NSF/AURA]

24 October 2017—The U.K.-based firm Teledyne e2v, one of the portfolio of imaging companies held by the international conglomerate Teledyne Technologies, announced in mid-October that it had secured a multimillion-U.S.-dollar contract from the SLAC National Accelerator Laboratory to supply CCD image sensors for the Large Synoptic Sky Telescope (LSST).

An 8.4-m telescope facility currently being built in Chile, the LSST will, when commissioned in 2021, commence a 10-year, comprehensive survey of the sky to address four key areas: dark matter and dark energy; hazardous asteroids and near-Earth objects; the “transient optical sky” (encompassing phenomena such as supernovae); and the Milky Way’s formation and structure. The telescope’s three-mirror design and imaging systems aim at producing “the deepest, widest image of the Universe”—and, at full design capacity, will suck in 15 terabytes of new data every night.

Forty-nine-moon imaging area

The cryogenically cooled imaging module that SLAC is assembling to record that data stream is billed as “the largest digital camera ever built for ground-based astronomy,” and each image it records will cover a patch of sky 49 times the area of the full moon. To fit out that camera, Teledyne e2v will provide an array of 189 large-area sensors that will deliver 3,200 megapixels of data per exposure.

Teledyne e2v says its sensors sport “very high sensitivity,” particularly in red wavelength regions, and a surface flatness precision “one-twentieth of the width of a human hair,” essential for accuracy on so large a focal plane. The company will wrap these precise components into a custom-packaged mosaic designed to minimize lost imaging area, and to keep the gap between individual sensor panels to only a quarter of a millimeter across a 630-mm-diameter focal plane. Sixteen output channels will enable the sensors to read out their image data in a matter of seconds, to accommodate the telescope’s huge nightly data load.

Another tool for multi-messenger astronomy?

Paul Jorden, a specialist in astronomy products at Teledyne e2v, noted in a press release that the telescope and camera “will stimulate the astronomy world with a huge survey data set which will be followed by many astronomers worldwide and will set a new standard against which other instruments will be compared.”

The high data throughput and the telescope’s ability to quickly detect changes in a patch of sky could prove particularly useful in the new era of multi-messenger astronomy. According to the LSST web site, the facility will repeatedly provide high-quality, high-resolution images of the entire night sky and continually compare them against one another. It will also generate alerts to the astronomy community within a minute of any detected change in the sky—“allowing the community to respond and catch events before they fade forever.”