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A telescope now under construction promises to revolutionize astronomy. It's being built atop a mountain in Chile, in the Andes. It's called the LSST. It is a survey telescope taking wide-angle views of the sky. And this telescope is expected to spot rare events that previously have been hard or impossible to find. NPR science correspondent Joe Palca toured the telescope's construction site.
JOE PALCA, BYLINE: The telescope is situated in an ideal spot for viewing the heavens. It's called Cerro Pachon, about 9,000 feet above sea level. Inside a large white building, about a dozen people have come for a look around.
JACQUES SEBAG: This is basically - what you see here is going to be a control room.
PALCA: Jacques Sebag is assembly manager for the telescope. We're in a large, brightly lit but very empty white room. The future control room is in a building connected to the telescope but a few levels below it. So we head upstairs and then file into a large cylindrical room.
SEBAG: Please come in. Be careful.
PALCA: The room is about 50 feet across, with concrete walls.
SEBAG: OK, everybody is in? All right. So now we're inside the pier. So everything around us, that structure, is to support the telescope.
PALCA: If we look up, we can see the sky. But that will change soon.
SEBAG: So in the future, when you come here, you will not see the sky. You will just see the bottom of the telescope.
PALCA: And that future isn't all that far off.
ROBERT BLUM: The real operations and starting to do the science will begin on October 1, 2022.
PALCA: Robert Blum is systems operation manager for the telescope. He says all the bits of the telescope are finished, or nearly so. The giant mirrors for capturing and focusing starlight are here on-site. The main telescope structure is on its way from Spain. The giant camera that will image the heavens is being finished in California.
BLUM: I think everyone has great confidence that we've solved all the really hard technical problems, and now it's just a matter of schedule and putting things together. So, yeah, it'll be a challenge, but we'll do it.
PALCA: LSST will have unique abilities. It can image the entire sky twice a week, so it'll be able to see faint objects like asteroids as they move across the sky. Caltech astronomer Mansi Kasliwal says it will also see much brighter celestial fireworks.
MANSI KASLIWAL: The fireworks that excite me the most are the ones that are only there - they're very powerful. So in a moment, the star becomes between a million to a billion times the brightness of the sun. But they're very, very short-lived. So these flashes could be as short as minutes to as long as few hours to a few days.
PALCA: There are a variety of events that could produce these flashes.
KASLIWAL: There could be two very dense stars merging. So for example, it could be two white dwarfs merging. It could be a white dwarf merging with a neutron star, a neutron star merging with a black hole.
PALCA: Kasliwal says although LSST will detect these events, other telescopes are better suited to study them in detail. So the plan is to send out an alert to other telescopes when LSST sees something interesting. Of course, that means the other telescope has to drop what it was doing, but Kasliwal says it will be worth it.
KASLIWAL: Because you have this short window of opportunity, and you want to make the most of what the universe wants to tell you before that flash of light fades away and is gone forever.
PALCA: And Kasliwal says LSST is certain to discover new phenomena the universe hasn't chosen to tell us about yet.
Joe Palca, NPR News.
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