Giant Magellan Telescope Set To Revolutionize Ground-Based Astronomy

StartsWithABang writes: If you want to see farther, deeper and at higher resolution than ever before into the Universe, you need four things: the largest aperture possible, the best-quality optical systems and cameras/CCDs, the least interference from the atmosphere, and the analytical techniques and power to make the most of every photon. While the last three have improved tremendously over the past 25 years, telescope size hasn't increased at all. That's all about to change over the next decade, as three telescopes — the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope — are set to take us from 8-10 meter class astronomy to 25-40 meter class. While the latter two are fighting over funding, construction rights and other political concerns, the Giant Magellan Telescope is already under construction, and is poised to be the first in line to begin the future of ground-based astronomy.

Comments

Re:Why on Earth? And why in Chile?

[careysub]

It's a cool idea, no doubt. But no matter how good your telescope is, I doubt it can easily surpass observing systems in space like the Hubble. At its altitude, roughly 25% of the atmosphere is beneath it, which reduces the problem of scintillation. Furthermore, the position in the Atacama Desert means it's a dry place, so there isn't a big problem with moisture causing differences in air density, leading to scintillation or even just refraction by the atmosphere. That said, why in Chile? Why not in Tibet, where it could be positioned at an even higher altitude but with many of the same favorable characteristics of being dry and away from light and air pollution? I recognize that it just isn't possible to build an observatory at the summit of one of the higher Andean peaks, but Tibet is probably a better place. That said, why don't we have plans (that I know of) for a replacement for the aging Hubble?

This is a raft of AC questions. In order the answers are:

• They can easily surpass Hubble in many ways, since in astronomy it is aperture, aperture, aperture, baby. Hubble is only 2.4 meters. It cannot compete in light-gathering power.
• Scintilllation is removed by adaptive optics, which have been in use for 30 years and are quite sophisticated now. This drives the resolution of these big ground-based scopes down below Hubble's resolution.
• No, the dry climate does not create a "a big problem with moisture causing differences in air density", just the opposite.
• The reason these telescopes are on islands (Hawaii, Canary) or on a high west coast mountain range is because of the laminar flow on air moving eastward (the jet stream and so forth) over thousands of miles of flat ocean (same is true of Hale, Mt. Wilson, Lick, etc.)
• Tibet is surrounded by thousands of miles of other high mountains creating lots of turbulence. Adaptive optics can do a lot but the technology isn't magic. The more stable the air the better.
• We do have plans for a replacement for the aging Hubble. It is the James Webb telescope, a 6.5 meter telescope due to launch in 2018, if the schedule does not slip (they will accept slippage to make sure it works properly).
• The one area where Hubble will remain unsurpassed is in high resolution ultraviolet astronomy. The ground-based telescopes can handle all optical band work quite nicely, the James Webb is designed to look at extremely distant objects with high red-shift which puts everything in the infrared (it does overlap the visual range slightly, it can see up to orange-red light), observations that cannot be done from the ground at all. High resolution ultraviolet observations are great, but not enough to justify (yet) a follow on replacement for that niche. There are other projects to do an ultraviolet all-sky (i.e. wide angle) survey which Hubble cannot do because of its narrow field of view.

For those who don't want to go to Forbes...

[spork invasion]

For those who don't want to visit Forbes, a site with a history of malware in their ads but insists that visitors disable ad blockers (and script blockers like Noscript)...

Here are a few links with more information than you'll get from Ethan's article, plus they don't require disabling ad blockers:
http://www.space.com/31079-giant-magellan-telescope-groundbreaking-travelogue.html
http://gizmodo.com/the-giant-magellan-telescopes-fourth-mirror-melting-is-1736954773
http://www.gmto.org/resources/

The technology is pretty damn cool, especially the adaptive optics to deal with atmospheric turbulence. It's worth a read, especially when you don't have to try to visit Forbes.

I really wish the Slashdot editors would stop letting this crap through. But because they do, it's a good service to everyone if users can provide alternate links that are better. In this case, there's a hell of a lot of good information on the actual GMTO site.

Groundbreaking was awesome

[dogvomit]

I was incredibly fortunate to be invited to the official groundbreaking event for the GMT last November, which concluded with one of the most memorable experiences of my life.

Just a couple of kilometers away from the GMT site are the twin Magellan telescopes. These telescopes are both 6.5 meter aperture and have a large number of instruments that astronomers can use, with fairly easy switching between instruments. That night the telescope staff did something extremely rare. They fitted the Clay telescope with an actual eyepiece and all 190 guests were allowed to look through this 6.5 meter telescope! (The president of Chile got to go first, of course.) For this event, the telescope was trained on the saturn nebula and with this much aperture the colors were quite striking even to human eyes.

One of the astronomers told me that the number of people who have actually looked through such a telescope doubled that night.