In one of the rooms of the SLAC National Linear Accelerator Laboratory previously used for elementary particle physics experiments, a team of engineers is completing the testing and final calibration of the light filters of what could be called the world’s largest digital camera to date. This camera, which we have already told our readers about many times, has a resolution of 3.2 gigapixels (3.2 billion pixels) and will be installed on the LSST telescope at the Vera Rubin Observatory, located on a mountaintop in Chile. The capability of this camera will allow the entire southern hemisphere night sky to be imaged in three days, and a complete overview of the entire sky will be done in an average of one week.
Images will be taken every 15 seconds, and all collected data will be included in one large set called the Legacy Survey of Space and Time. This dataset will be collected over a 10-year period and will include data on the location, shape, and spectral characteristics of millions of stars and billions of galaxies. A sufficiently high rate of imaging will allow astronomers to “keep their eyes peeled” for asteroids close to our planet, to further study and understand the processes of Milky Way evolution, to discover something new about the nature of dark matter and dark energy, and most likely to discover cosmic phenomena of entirely new, as yet unknown today, types.
Each night, the camera will produce 15 terabytes of data on the brightness, spectrum, location and shape of objects in its field of view. This data will go through preprocessing and will be used to automatically generate about 10 million notifications, the most important of which will be sent to a predetermined list. Note that scientists-astronomers, astrophysicists and cosmologists are constantly exchanging such notifications, sent manually, by which they alert their colleagues about new and interesting phenomena found in the depths of space.
The camera front consists of three lenses and one of the interchangeable light filters that direct light into the camera and focus it on a plane measuring 3 by 1.65 meters. On this plane, there are 189 CCDs arranged into 21 groups of nine arrays. The planes of all matrices are aligned so that the deviation of any one of them from the common plane does not exceed 10 microns. And all of these together will be cooled to a temperature of -100 degrees Celsius to reduce thermal noise in the resulting images.
The LSST also has six light filters mounted on a pivoting design, allowing for quick filter changes and adapting the camera to the current shooting conditions. The filters enable the camera to record at six different ranges of the electromagnetic spectrum from near infrared to near ultraviolet.
When the LSST camera arrives in Chile, it will be positioned between three mirrors. The main mirror is 8.4 meters in diameter, and the last one is 5 meters. Between them there will be an intermediate mirror, 3.42 meters in diameter, which, according to available information, is the largest convex mirror made by people in history.
Note that the original plan for the LSST telescope was to install the camera back in 2014. But due to a series of delays, most recently related to the COVID-19 pandemic, the event was repeatedly postponed to a later date. “Had it not been for COVID-19, we would have received the camera in Chile a year ago,” says Steven Kahn, astrophysicist and director of the observatory, “But just now this device is very close to the final stages of its assembly and preliminary setup.”
According to the adjusted current plan, the LSST telescope should see its “first light” in January 2023. And at its full capacity, this facility should come out by October of the same year. And hopefully, the new camera will allow scientists to find answers to some of their unresolved fundamental questions.
