System test images released
The successful completion of these tests sets the stage for the final step of Rubin construction: the installation of the 3200-megapixel LSST Camera (LSSTCam), the largest digital camera in the world.
Over a seven-week engineering test campaign, from 24 October to 11 December 2024, approximately 16,000 exposures were acquired to test Rubin Observatory’s hardware and software systems and data pipeline.
Known as ComCam, the engineering test camera is a much smaller version of the mighty LSSTCam. With 189 CCD sensors, LSSTCam’s field of view will be 21 times that of ComCam, with each single image capturing an area on the sky about 45 times the size of the full moon.
The LSSTCam will be installed on the telescope in place of ComCam, where it will help carry out Rubin’s 10-year Legacy Survey of Space and Time. Coupled with Rubin’s fast-moving, 8.4-metre telescope, the LSSTCam will capture very faint objects and objects that change in position or brightness at a rate the science community has never seen before.
The tests conducted by Rubin’s international commissioning team, which is composed of hundreds of engineers, scientists, and observing specialists, included:
- Verifying the Active Optics System that maintains the precise positions and shapes of the telescope’s three large mirrors as the telescope points in different directions
- Checking that the telescope’s complex systems were all working together
- Demonstrating the early image quality capabilities of the system in all six filters
- Shipping the large amount of data quickly from Chile to the Rubin Data Facility at the Department of Energy’s SLAC National Accelerator Laboratory
- Running the complex data processing pipelines
“The success of the engineering test phase has given a surge of excitement and anticipation to the team,” says Sandrine Thomas, Deputy Director for Rubin Construction. “Reaching this milestone has offered a small taste of what is to come once Rubin Observatory begins its 10-year survey.”
Read more at rubinobservatory.org/news/rubin-completes-comcam-tests
A good comparison of the ComCam engineering test camera with the LSSTCam can be seen in the figure below. The two have the same resolution and sensitivity, but the LSSTCam covers 21 times more area on the sky in every image. A single test engineering image from the very first night of the ComCam campaign is shown in the context of the coverage that will be provided by the LSSTCam: every one of the 21 squares in the teal wire frame is equivalent to another ComCam, all observing the sky at the same time. As ComCam already covers an impressive area equivalent to two full Moons, the promise of the full LSSTCam is incredible.
