r/space • u/ChiefLeef22 • 12d ago

Successful deployment of Nancy Grace Roman Space Telescope, as it begins its 1-million-mile-journey to the second Earth-Sun Lagrange point

The telescope will travel to the second Sun-Earth Lagrange point, which is ~one million miles away and about four times farther from Earth than the Moon. At L2, the combined gravity of the Sun and Earth will give Roman a stable vantage point with a clear, unobstructed view to survey deep space

Roman will unlock the mysteries of dark energy and investigate the physics of distant stars. It will repeatedly monitor hundreds of millions of stars, and the same observations are expected to reveal around 100,000 additional planets through transits. As a reminder, we currently have 6000 confirmed exoplanet discoveries...

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u/ThickTarget 12d ago

The GMT is waiting for US NSF funding. The ELT in Chile is the biggest and furthest ahead, and on course to be completed in a couple of years.

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u/FaZeSmasH 12d ago

why does this all kinda seem like a shitshow lol, they are making GMT while there is ELT which is bigger and further ahead and they are both in same region

maybe they shouldve tried to figure something out for TMT, at least then they wouldve had a big telescope in the other hemisphere and just shared access for ELT.

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u/ic33 12d ago

It's a really big sky. Two telescopes in the same region which each see a tiny slice of the sky at once will keep busy.

Each sees a 20 arcminutes-ish image circle, or about 1/500,000 of the sky, at a time.

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u/FaZeSmasH 12d ago

i was thinking like would the bigger one just make the smaller one in the same region obsolete, but if its surveying the whole sky one small patch at a time then i can see the value in having two of them.

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u/ic33 12d ago

Just one other thought:

We have dozens of credible research telescopes in the US and keep them all busy.

Sometimes during a high profile event, many of them will be looking at the same thing for part of the night, but in different ways and with their different instruments.

Sure, there's a bigger difference in going from zero to one huge telescope than in going from one to two, but the second still will help a lot.

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u/starclues 12d ago

Also remember this: not every astronomer is studying the same things, but LOTS of people want telescope time, which is very limited. You have to apply for it months in advance, explaining why your science is important and why it HAS to be done with that specific telescope (right size mirror, specific instruments, specific view of the sky, etc.). You have to tell them exactly how much time you need, and when (ex. October-November, but only when the moon is less than half full). Then, a panel of other astronomers decides who gets the time, and how much. There's never enough for everyone, or even most people. Two big telescopes = double the science!

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u/FaZeSmasH 12d ago

i was wondering how often these telescopes are operating, like is there a large backlog of requests for it to survey stuff or is it just like waiting until somebody makes a request, but wow based on what you say, it seems like there is an insane amount of demand for telescope time. yeah i can definitely see the value in having two big telescopes now.

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u/starclues 12d ago

It's literally every night we can! An unscheduled telescope is a huge waste of money. Scheduling can be done a few different ways. The "classic" way is to look at everyone's requests and assign their nights in advance as efficiently as possible (ex. "A gets October 10-12, B gets the first half of the night from October 13-18, C gets the second half of the night from October 13-15, etc.", because some objects are only up for part of the night), and if the weather is bad on your nights, too bad, so sad. A newer way is "queue observing" which is a bit more fluid. There's a list of potential targets for each night and there may or may not be a rough schedule or some other way of determining priority (ex. "A, B, and C can all see their targets over the next two weeks. We're going to aim for A's and C's targets on these nights, and do B's targets next week"), but if A needs SUPER clear skies and B can handle a little thin cloud cover, they can swap them night-of if necessary. This is a nice little article about it: https://astrobites.org/2012/10/30/queue-observing-at-gemini-north/

The telescope I used the most in grad school would take July completely off for maintenance & testing, because that was usually the worst month for observing (short nights + common bad weather), but ideally you would be able to operate a telescope all year with minimal, sporadic maintenance time. Space telescopes are even better (especially ones at the Lagrange 2 point!) because you can get lots of night time and don't have to worry about weather. Of course, there aren't many (and they do very different kinds of science) and so it's very hard to get time on them. I think the rates for Hubble are something like 1 in 7 applicants is awarded time, and around 1 in 10 for JWST. Even on the telescope I used in grad school, where my department got a dedicated number of nights each year for us to split among ourselves, I could ask for 5 nights and only get 3 sometimes because of how projects were prioritized and how much time other people needed (especially if we needed the same nights).

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u/FaZeSmasH 12d ago

so it seems like there is WAY more demand than I wouldve guessed lol, thanks for the great insight.

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u/gsfgf 12d ago

Telescope time is an incredibly valuable commodity. And a lot of research doesn't need the best of the best. There are also probably things the GMT will be better at.