The Vera C. Rubin Observatory, previously known as the Large Synoptic Survey Telescope (LSST), will be the first observatory of its kind. Jointly funded by the National Science Foundation (NSF) and the Department of Energy (DOE), Rubin will conduct the Legacy Survey of Space and Time (LSST) – a 10-year survey of the southern hemisphere. The observatory is expected to collect 15 terabytes of data a night, which will be used to create an ultra-wide, ultra-high-definition, time-lapse record of the cosmos, containing tens of billions of stars, galaxies, and astronomical objects.
After ten years of construction, the Vera C. Rubin Observatory is less than one year away from starting this revolutionary observation campaign. In preparation for this, the observatory recently completed a series of full-system tests using an engineering test camera. With this milestone complete, the stage is now set for the installation of the 3200-megapixel LSST Camera (LSSTCam), the world’s largest digital camera. Once mounted on the Simonyi Survey Telescope, the observatory will have finished construction and be ready to collect its first light.
The engineering test camera, the Commissioning Camera (ComCam), is a much smaller version of the LSSTCam. It relies on a mosaic of nine 3.2-megapixel Charge-Coupled Device (CCD) sensors, providing a total area coverage of 144 megapixels – about twice the size of a full Moon. During the ComCam engineering test campaign, which took place from October 24th to December 11th, 2024, the camera acquired approximately 16,000 exposures to test the Rubin Observatory’s hardware, software, and data pipeline.
The tests were conducted by Rubin’s international commissioning team, composed of hundreds of engineers, scientists, and observing specialists. According to a statement issued by the Rubin Observatory, the test included verifying that the telescope’s complex systems were all working together, testing the early image quality in all six of the system’s filters, and running the data processing pipelines. They also verified that the system can transmit large amounts of data from the observatory to the Department of Energy’s SLAC National Accelerator Laboratory.
They also confirmed the Active Optics System (AOS), which maintains the precise positions and shapes of the telescope’s three large mirrors. The Simonyi Survey Telescope, the camera, data systems, networks, and everyone involved in the engineering test were said to have performed exceptionally well. The test delivered high-quality images within the first hours, even though most of the detailed optical adjustments and environmental controls were not fully activated. Per the statement:
“Thanks to the dedicated efforts and talents of thousands of people over many years, the telescope had been assembled with all its complex parts positioned correctly to better than about one millimeter. Equally satisfyingly, the high-speed network connecting Chile and the data center at SLAC, the data systems, and the algorithms for analyzing the data worked well, too.”
The LSSTCam has 189 CCD sensors, giving it a field of view roughly 45 times the size of a full Moon – over 21 times that of the ComCam. For the final phase of construction, the LSSTCam will replace the ComCam on the Simonyi Survey Telescope. When coupled with this 8.4-meter (27.5-ft) telescope, the LSTTCam will capture images of very faint and variable objects at an unprecedented rate. The installation will take a few months, followed by the observatory capturing its “First Look” images of the cosmos.
“The success of the engineering test phase has given a surge of excitement and anticipation to the team,” said Deputy Director for Rubin Construction Sandrine Thomas. “Reaching this milestone has offered a small taste of what is to come once Rubin Observatory begins its 10-year survey.” Once the final testing and verification phase is complete, the Rubin Observatory will begin the most comprehensive data-gathering mission ever performed in the history of astrophysics.
The observatory is named in honor of American astronomer Dr. Vera C. Rubin, whose work was foundational to the theory of Dark Matter. By repeatedly scanning the southern sky with its cutting-edge instruments for a decade, Rubin will create an ultra-high-definition time-lapse record of the cosmos. This data will allow scientists to investigate Dark Matter, Dark Energy, and other mysteries facing astronomers, astrophysicists, and cosmologists today.
Further Reading: Rubin Observatory
