How do you test new sensors for the world’s largest digital camera? You take a picture of broccoli, of course.
This may sound bizarre but the intricate shapes found in the Romanesco version of this plant are a good check if you are capturing a lot of details.
And for the camera that has to be installed at the Vera Rubin Observatory in Chile – performance is everything.
This 3.2 gigapixel device is supposed to help unlock some important outstanding questions in astronomy.
Who knows? Even this can get us closer to understanding those cosmic head-scratches “Dark Energy” and “Dark Matter”, which control the development of what we see when we look.
VRO will make it what can only be described as a magnificent map of the sky.
The observatory is going to survey its entire area every few nights for 10 years.
Not only will Rubin look at the position of billions of stars and galaxies, but it will capture anything that moves or glows. It will be a treasure trove of data that will keep scientists busy for decades.
But to conduct such a survey, the VRO requires a special camera – such as is now being assembled at the SLAC National Accelerator Laboratory in California.
At its heart is a 64 cm wide focal plane made up of 189 individual sensors or charge-coupled devices (CCDs). Mounting them all safely and properly and their complex electronics talking to each other is a huge challenge.
But the pictures released on Tuesday show that the work has been successfully completed.
The SLAC team is not yet in possession of all components of the camera, such as its lens, so it projects images onto the CCD array using a 150-micron pinhole.
The Brassica plant was deliberately chosen for its very wide surface structure. Innumerable knots and bumps. To take account of a ton.
Just how good are the pictures? If you want to display them full size at full resolution, you will need a 378 4K ultra-high-definition TV screen.
“If we are completing this survey of the sky, we need a larger telescope and a larger camera,” explained VRO director Steve Kahn.
“This three billion pixel camera will cover about 10 square degrees of sky; and to make you feel like it’s about 40 times the size of a full moon. And we’ll be taking pictures in the sky every 15 seconds . “He told BBC News.
“We’ll get very deep images of the entire sky. But more importantly we’ll get a time sequence. We’ll see which stars have turned into flashes, and anything that has gone through the sky like asteroids and comets has gone. “
Vera Rubin is primarily an American project, but with a strong international dimension.
UK scientists are expected to play a large role in the analysis of data, with much expertise in the work of sky survey.
VRO has been in the spotlight due to its potential vulnerability to recently launched satellite mega-constellations.
A large number of low-orbiting telecommunications spacecraft passing through the camera’s field of view can ruin its images.
The largest of the new mega-constellations – currently – is being lofted by entrepreneur Elon Musk and his space company.
Prof. Kahan stated that the VRO was engaged with Mr. Musk and the engineer was working on a solution to limit interference.
The observatory director said that better engagement with the now British-Indian-owned OneWeb company was needed.
The satellites of this network can eventually pose a bigger problem than SpaceX because the spacecraft is higher in the sky and will remain in the VRO’s field of view longer.
Professor Khan told BBC News, “Britain’s astronomy has gathered a large collaboration, so it may be helpful for them to work to support OneWeb.”
“These problems are not completely insoluble, but you need proper cooperation.”
The VRO’s camera is expected to begin taking images of the sky in late 2022 – unlike the heads of broccoli.