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LSST Camera Workshop Digs into the Details

LSST camera with a 6 foot person for scale. (image: LSST Corporation.)

Today the Large Synoptic Survey Telescope camera team concludes a five-day workshop, which brought together an international body of about 50 scientists and engineers to discuss technical progress and ongoing development. The meetings and breakout sessions, held in SLAC's Panofsky and Kavli Auditoriums, focused on collaboration and design specifics for what will be the world's largest digital camera.

"The goals of the meeting were to discuss key issues and requirements, promote communication with partner institutions and generate a clear path forward for upcoming reviews," said Nadine Kurita, a mechanical engineer at SLAC and camera project manager for LSST.

Separate teams, representing nearly 30 institutions, are designing different components of the camera and the meeting's main challenge was figuring how to have the respective pieces work smoothly together. An important goal was making sure that the camera's lenses, filters, shutter and 65-centimeter diameter silicon detector plane will interface correctly. In a talk about development plans on Monday, Dick Horn, a former systems engineer from NASA's Goddard Space Flight Center, stressed integration across all subsystems and cautioned that the teams are "not designing in a vacuum or a stovepipe."

The camera's design, overseen by the Kavli Institute for Particle Astrophysics and Cosmology at SLAC and Stanford University, makes use of groundbreaking technology, some of which is still being developed. An extraordinary 189 charge-coupled devices, or CCDs—the technology behind half of this year's Nobel Prize in physics (see sidebar)—will sit at the telescope's focal point and allow the camera to capture a larger fraction of the sky in one shot than any existing telescope. Having such a wide view provides an all-seeing snapshot of the universe, increasing the likelihood of catching rare occurrences and allowing better studies.

Over the course of the week, the LSST camera workshop attendees looked at many issues, including management, temperature regulation, optics, mechanical controls and funding appropriations for the telescope's $500 million budget. Those present argued, sometimes quite emphatically, about design specifics, but intend to reach their upcoming design deadline. The disparate components must be finalized by late 2010 in order for the telescope to achieve first light in 2016.

Deputy LSST Project Director Steve Kahn mentioned that this workshop also represented a critical milestone for LSST, as it coincided with the Astro2010 meeting, from October 4–6 in Washington, D.C. Astro2010 is the latest in a series of decadal surveys that rank all currently proposed astrophysics projects based on their importance to the field. The highly influential ranking, read by congressional committees, the scientific community and the public, is critical for LSST, which relies on federal funding. The project has been near the top of the list on other national reports and workshop participants indicated there is no reason to expect otherwise here.

From its eventual perch in northern Chile, the LSST will be capable of simultaneously observing faint, far objects and nearby, fast-moving ones. The 3,200 megapixel, SUV-sized camera will take rapid exposures and provide some of the most expansive pictures of stars and galaxies ever created. The detectors will address the spectrum between infrared and visible red light, a band for which surveys of major fractions of the sky have not previously been available. Each night, the project will produce 30 terabytes of data, which will be housed in new computing systems being developed just for LSST.

When completed, the camera will provide a one-of-a-kind perspective on the sky; fast, wide and deep. Scientists hope to use it for studies of weak lensing—the bending of distant starlight by the gravity of nearer objects—which could lead to a better understanding of dark matter and the formation of galaxies and galaxy clusters. Looking to the farthest reaches of space and time with the telescope could help explain the accelerated expansion of the universe due to dark energy. The LSST collaboration plans to make its images available through an online database, providing alerts to interested parties and a nearly limitless pool of data for discovery. 

—Adam Mann
SLAC Today, October 9, 2009