Technicians put the finishing touches on the world’s largest digital camera at SLAC National Accelerator Laboratory. The camera will be sent to Chile and installed on a telescope in the Andes.
MARY LOUISE KELLY, RECEPTIONIST:
The world’s largest digital camera is almost ready. Scientists expect exciting discoveries when the 3.2 billion pixel camera is connected to the telescope. NPR science correspondent Joe Palca recently visited the lab where the camera was built.
JOE PALCA, BYLINE: The camera is being built at the Energy-funded SLAC National Accelerator Laboratory in Palo Alto, California. This camera is huge. It weighs three tons and is two stories tall. When I visited earlier this month, it lay horizontally on a large steel platform.
AARON ROODMAN: The lens cap is still on, so we can’t look at the business end.
PALCA: Aaron Roodman is the camera program manager. We’re in a high-ceilinged clean room, wearing Tyvek hoodies, sweatpants and booties, and latex gloves to avoid contaminating the equipment inside the camera. Sitting on its side, the camera body feels a bit like a jet engine to me.
ROODMAN: So you want to go up – should we go up to the platform to get a closer look?
PALCA: We climb half a dozen metal stairs to the platform. We are now just inches away from the camera body – close enough that I can touch it. Roodman says no.
ROODMAN: That’s OK if you did, but let’s try not to.
PALCA: Oh, okay.
ROODMAN: Yes. Let’s not…
PALCA: Well, you know, every kid wants to touch it.
ROODMAN: I know. Let’s try not to touch it. I don’t think anything would happen if you did…
ROODMAN: …But it’s just good practice not to.
PALCA: Roodman’s caution is understandable. If I spent $168 million on a camera, I wouldn’t want people messing with it either. And there is nothing like this camera. To keep the equipment cool are custom-made lenses, filters, custom electronics, a giant shutter and special cooling, all packed into a cylindrical camera body.
ROODMAN: In this configuration, it’s just – it just feels congested, but to see everything together like that is fantastic.
PALCA: The Vera Rubin Observatory in Chile, where the camera is pointing, is also unique. Its telescope is designed to see a large chunk of the sky at once, so it needs a huge camera to capture images. Each night, the camera is expected to generate 20 terabytes of data.
ROODMAN: We are currently planning to send the camera to Chile in April.
PALCA: It should be a joyous time for the people working on this project. The camera is almost ready. The telescope is also almost ready, and Roodman and his colleagues are quite optimistic. But there is a problem that no one thought of when the telescope was created – communications satellites, thousands already in orbit, many more to come. They are usually invisible to the naked eye. But for a telescopic camera, they are bright objects.
ROODMAN: They’re anywhere from medium disruption to major disruption. This is not a good development for us at all.
PALCA: You can write a computer program that removes satellites digitally. But because the Vera Rubin telescope sees such a large piece of the sky at once and there are so many satellites, it’s difficult to remove them all. Tony Tyson is the chief scientist of the new observatory. It was designed, he says, to find what Tyson calls “go bump in the night” — objects that aren’t there one night but appear a day or so later. They could be exploding stars or stellar collisions or something completely new to science. Satellites can make this a problem. Tyson says that when a telescope sees something unusual like this, it signals other telescopes to look at that part of the sky, so anything that hit during the night can be studied in depth.
TONY TYSON: I think we have a lot of false positives – false positives. That worries me the most.
PALCA: Things that the software misidentifies as new but are actually just a reflection from a satellite. A false clue sends the other telescopes on a wild goose chase. Tyson says some companies, such as Starlink, have agreed to take steps to mitigate the problem, such as using less reflective material in their satellites. Other companies have not been so responsive. Tyson says they won’t know exactly how much of a nuisance these satellites will be until they mount a camera on a telescope and start looking at the sky. Joe Palca, NPR News.
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