Largest telescope coming

[ToSeek]

The 7x8.4 meter Giant Magellan Telescope (http://helios.astro.lsa.umich.edu/magellan/index.php) has been funded. (http://www.chron.com/cs/CDA/ssistory.mpl/topstory/2719724)

Astronomers working on the project hope to accomplish two things, Lambert said. A larger telescope could allow them to see very distant objects in the universe so they can look back in time to when the first galaxies were being assembled. Also, the sharper imaging of the new telescope could allow them to provide the first images of planets around nearby stars.

[Glom]

A cluster of mirrors? How post modern!

If it does manage to out do Hubble, do you think it will make more of a public impact being ground based?

[Trebuchet]

Woof! That's roughly five times the size of Palomar, which is what I remember as being the largest telescope when I was a kid.

What's the largest current telescope?

[Brady Yoon]

I think it's either the VLT (very large telescope) or the Hale on Mauna Loa. I'm not sure though.

[Glom]

Arecibo is the largest single dish, IIRC. But interferometers like VLT are effectively bigger.

[Padawan]

2015 is nowhere in the future though. It would have been very awesome to see images captured by that telescope!

[ToSeek]

Woof! That's roughly five times the size of Palomar, which is what I remember as being the largest telescope when I was a kid.

What's the largest current telescope?

Here's a list. (http://www.seds.org/billa/bigeyes.html)

[Kullat Nunu]

I think it's either the VLT (very large telescope) or the Hale on Mauna Loa. I'm not sure though.

It depends how you define the largest telescope. Keck atop Mauna Kea has two fully-usable 10-m mirrors (Mauna Loa is an active volcano; you wouldn't like to build a telescope there ;) ), in that sense it is the largest. VLT has 4 x 8 meter telescopes, and has longer interferometer baseline than Keck so it has better resolution. Hobby-Eberly Telescope has the largest mirror, but it is not fully steerable and the whole mirror area cannot be used same time. Hale Telescope on Palomar Mountain was the largest telescope for decades, but it will soon drop from the Top-10.

This list (http://en.wikipedia.org/wiki/List_of_largest_optical_reflecting_telescopes) has all the world's largest mirrors listed.

[Kullat Nunu]

The Overwhelmingly Large Telescope (http://www.eso.org/projects/owl/) is probably the most megalomanic ground-based observatory project currently under study. :o

[ToSeek]

Hale Telescope on Palomar Mountain was the largest telescope for decades, but it will soon drop from the Top-10.

And us old-timers will observe a moment of silence. It was the telescope for quite a long time there.

[Harvestar]

Very good. :) Can't wait 'til they start casting the mirrors. That will be an interesting project. :) (especially the special polishing and testing)

And the LBT is actually the largest single mirror in the world (8.4 meters) - and there are two mirrors. First light should be this fall - the first mirror is up at the telescope now - just needs aluminium.

[ngc3314]

Hale Telescope on Palomar Mountain was the largest telescope for decades, but it will soon drop from the Top-10.

And us old-timers will observe a moment of silence. It was the telescope for quite a long time there.

Too late - it's long gone. I was just noticing in a textbook for this fall that (if you count the VLT as four, and include SALT and the La Palma 10.4m) the Hale telescope has dropped to about number 15. In fact, the half-page table in this book doesn't even make it down to 6.0 meters, thereby including telescopes finished after, umm, 1993. So this includes (going from memory here, let's see how it works out):
1. 10.4m GTC
2-3. 10m Keck x 2
4. 9.2m HET
5. 9.2m SALT
6. 8.4m Subaru
7. 8.3?m LBT (one so far, will rise in the list)
8-9. 8.2m Gemini N and S
10-13. 8m VLT (x4) (since they usually work separately)
14-15. 6.5m Magellan (Clay/Baade) x2
16. 6.5m New MMT


I think the next entry on the list would be the 6-meter Bol'shoi Teleskop Azimultalnyi, oddly enough the largest with which I've observed on-site, followed finally by Palomar at number 18!

And the Giant Magellan all by itself will point as much glass as the VLT+Gemini+Subaru. I hadn't even heard of this one coming!

[George]

Yee Ha and Gig 'em! :) You can hardly see the people in the drawing!

It's great to see A&M advancing. When I took Astronomy 101 there, they used an 9 year old b&w only text book. It was taught by the driest calculus prof. I ever had. I was so let down, I didn't get interested again in Astronomy till some "bad" guy started a coloruful astronomy internet forum. :)

[Harvestar]

And the Giant Magellan all by itself will point as much glass as the VLT+Gemini+Subaru. I hadn't even heard of this one coming!

Yeah, my boyfriend and I were talking yesterday about this and he said, "Wow, just yesterday it was just some Roger Angel dream... and now it has money!"

At Arizona it's been talked about often and we had to "design" the AO system for the GMT for our Adaptive Optics homework last year.

[01101001]

Work Begins on Giant Magellan Telescope (http://www.universetoday.com/am/publish/work_begins_mgto.html?13122004)

GMT (http://www.gmto.org/)

[George]

Work Begins on Giant Magellan Telescope (http://www.universetoday.com/am/publish/work_begins_mgto.html?13122004)

I like their expectations...

The GMT will have ten times the resolution of the Hubble Space Telescope.
=D>

[Evan]

Work (http://www.hia-iha.nrc-cnrc.gc.ca/VLOT/index.html) is starting on the design of a 20 metre telescope to replace the CFHT on Mauna Kea.

[Russ]

They say here (http://www.universetoday.com/am/publish/work_begins_mgto.html?13122004[/url)

“The Giant Magellan Telescope will allow an unprecedented view of extrasolar planets as well as a window out to the largest scales and back to the earliest moments of the universe.

Does this mean that they will be using the multi-mirror design as an optical interferomiter? As big as it is/will be, I don't think it would have the resolution to pick a planet out of stellar glare otherwise.

[badprof]

Work (http://www.hia-iha.nrc-cnrc.gc.ca/VLOT/index.html) is starting on the design of a 20 metre telescope to replace the CFHT on Mauna Kea.

Yikes!!!!! The secondary is 2.5metres!!!!!!!!!!!!!!!!!!!!! :o :o

I would love to get access to a scope that has a primary that size!!!!! :(

Maurice

[Ut]

Looking at the picture, I'm guessing no. They're just using 7 mirrors to simulate a single 25m mirror. I'm not sure you're really grasping how big 25 metres is, though. That thing'll have a diameter twice the length of my house! And it's diffraction limited angular resolution will be ~0.004 arcseconds. That's a lot o' detail.

[Russ]

Looking at the picture, I'm guessing no. They're just using 7 mirrors to simulate a single 25m mirror. I'm not sure you're really grasping how big 25 metres is, though. That thing'll have a diameter twice the length of my house! And it's diffraction limited angular resolution will be ~0.004 arcseconds. That's a lot o' detail.

Thanks for the response. I do know how big 25m is. It's the length of the biggest sailboat I've ever been on, 81 feet.

Despite it's very fine angular resolution, planets are far too faint to be seen through the glare of the host star. Since it will be operating at optical wave lengths, interferometry is the only way I can think of to reduce the stars' glare enough to see the planets. Or am I wrong about something?

[George]

Looking at the picture, I'm guessing no. They're just using 7 mirrors to simulate a single 25m mirror. I'm not sure you're really grasping how big 25 metres is, though. That thing'll have a diameter twice the length of my house! And it's diffraction limited angular resolution will be ~0.004 arcseconds. That's a lot o' detail.
How would this resolution differ in an interferometer with a 25 meter baseline? [I know light gathering would be a major difference but the SPIRIT project, with variable baselines, has me confussed regarding resolution.]

[Russ]

Looking at the picture, I'm guessing no. They're just using 7 mirrors to simulate a single 25m mirror. I'm not sure you're really grasping how big 25 metres is, though. That thing'll have a diameter twice the length of my house! And it's diffraction limited angular resolution will be ~0.004 arcseconds. That's a lot o' detail.
How would this resolution differ in an interferometer with a 25 meter baseline? [I know light gathering would be a major difference but the SPIRIT project, with variable baselines, has me confussed regarding resolution.]

The resolution wouldn't be affected one way or the other. It is the ability to cancel out the light from the host star by setting up interference patterns with the star light while still gathering the maximum available light from any planets obiting said star.

What I was trying to find out, is this scope able to do interferomitry or is there some other technique they use to see the planets. I suppose that there could be a misstatement in the article. :roll:

Anybody know what reality is in this matter?

[ngc3314]

Looking at the picture, I'm guessing no. They're just using 7 mirrors to simulate a single 25m mirror. I'm not sure you're really grasping how big 25 metres is, though. That thing'll have a diameter twice the length of my house! And it's diffraction limited angular resolution will be ~0.004 arcseconds. That's a lot o' detail.
How would this resolution differ in an interferometer with a 25 meter baseline?

The resolution wouldn't be affected one way or the other. It is the ability to cancel out the light from the host star by setting up interference patterns with the star light while still gathering the maximum available light from any planets obiting said star.

What I was trying to find out, is this scope able to do interferomitry or is there some other technique they use to see the planets. I suppose that there could be a misstatement in the article. :roll:

Anybody know what reality is in this matter?

Checking the "science case" draft at the GMT project site, IR imaging of bright extrasolar planets is a goal. They plan to do [i]ground-layer adaptive optics essentially all the time. This would use the secondary mirror as an adaptive element to remove the scrambling of images that happens in a turbulent layer fairly low to the ground. While not as sharp as some other AO approaches, this should work over a wider field than any yet demonstrated. They thus plan on a usual seeing of 0.3-0.4 arcseconds over a field of many arcminutes. On top of that, one could use higher-order adaptive systems, especially so-called multiconjugate systems that correct for several layers in the atmosphere (usually conceptualized with a hexagon of lasers around the targeted position). The key for this project (and things like quasar host galaxies) is not just resolution, but how well you can get rid of the small fraction of scattered light outside that central core. You'd need rejection at the million-ot-one level at a separation of a couple of arcseconds for the kinds of planets we mostly think of imaging.

There are things one could do with multiple movable mirrors that might act like nulling interferometry, but I don't remember any discussion there from a cursory reading.

[Tom Mazanec]

Any prospect on these things actually being built? I will take a single 30m scope that actually exists over a dozen 100m projects that are just paper studies, or are even started only to be abandoned like the Superconducting Super Collider was.