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Engineering the 30-Meter Telescope
yyzmcleod writes "When completed in 2018, the Thirty Meter Telescope (TMT) will be the world's largest and most powerful, with a resolving power 100 times that of Hubble. As TMT's preliminary design review nears, this article details how its enclosure, segmented mirror and adaptive optics will work to let astronomers peer back to the beginning of the Cosmos."
I was hoping for the Thirty Meter Nano-Telescope (TMNT)
Correct link without the 501 error: http://www.canadianmanufacturing.com/designengineering/features/industryfocus/article.jsp?content=20090512_125904_8252
Do not despair, the article is here.
"World's largest and most powerful".
Yeah, except for the 42-m E-ELT, also slated for 2018-ish. And that's still excluding radio telescopes...
This telescope design has a lot of promise.
My father is an optical designer/astronomer, and I grew up around many different designs that actually do work.
Why is a long telescope important? Well, once you eliminate the tube sag, it has certain properties.
This design almost eliminates ambient light (think of looking at the moon through fog compared to looking at the moon on a clear night in the mountains).
Because of this, even "tiny" 6-inch long-tube designs can match or exceed 24" or better telescopes in detail and quality. The design is out of fashion with the general public mostly because of portability and ease of use.
The design of this telescope in specific almost TRIPLES the effective length of the telescope, making the ambient light-reducing qualities much more enhanced.
Something like this would be able to look at ultra-distant objects with excellent image quality, putting spy satellite image quality to shame.
I have one caveat with this design though, I'm not very fond of the Cassegrain system because the quality of the optics is often sacrificed in the process of creating them.
There are no perfect answers, only the right questions. More questions at http://foresightandhindsight.blogspot.com/
2018 !, I wanted to use the 30 meter telescope to fry ants in other galaxies now !, or maybe see some boobs.
R.Morton
modded quote "what's that he's talking about? Windows , Never had a problem with Windows till I tried to use it."
"...to let astronomers peer back to the beginning of the Cosmos."
I remember that. It had music by Vangelis and a Seyfert galaxy in the forward view screen.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
As the actual article notes on its first page, TMT will have roughly 100 times the collecting area of Hubble: this goes as the square of the diameter of the telescope, so with TMT = 30m and Hubble = 2.5m, that's about right.
Resolving power (if the TMT can be made diffraction-limited, which it is aiming to do, but which is hard nevertheless) gets better linearly with the diameter, so TMT will have roughly 10 times the resolving power of Hubble.
The more appropriate space-based comparison in 2018 will be JWST which has a diameter of 6.5m, although JWST and ground-based ELTs are more properly thought of as being complementary, not competitive: they do different things.
But as already noted, the more appropriate comparison is with the European E-ELT which is under Phase B study now and is baselined for 42m diameter.
More interesting is where the TMT and E-ELT will be located: same hemisphere or not? Current bets are on E-ELT being in Chile, with TMT possibly going to Mauna Kea. This would be a better outcome for us astronomers than having both in the south, IMHO.
As I said, ground- and space-based telescopes are actually highly complementary: it sounds greedy, but we really need both.
Space has the advantage of there being no atmosphere to block some of the incoming light and blur the image. Also, if you cool your telescope down (e.g. ESA's Herschel being launched tomorrow and NASA/ESA/CSA JWST in 2014), then you benefit from greatly reduced sky background at infrared wavelengths. This can result in an enormous increase in sensitivity in situations where the background matters, e.g. imaging of extremely faint sources.
Also, space-based telescopes can cover a wider wavelength range, including wavelengths that don't make it through the atmosphere, so some kinds of thing must be done from space (e.g. X-ray astronomy as in NASA's Chandra and ESA's XMM-Newton).
At the same time, space telescopes are much smaller than state-of-the-art ground-based ones, and thus the ground-based telescopes can catch many more photons over all. For some science (e.g. medium- to high-resolution spectroscopy of extremely faint objects where the background doesn't matter), it's all about the number of photons you can collect.
Also, if you can implement adaptive optics on your ground-based telescope, you can get higher resolution than in space.
As an example of true synergy, look at the many studies done jointly by HST and the ground-based 8-10m telescopes like the VLT, Keck, Gemini, and so on. In many cases, both were needed to complete the study.
Indeed, there are many of us helping develop both JWST and ground-based ELTs like E-ELT and TMT for exactly the same reason: we need both to get a more complete picture of what's going on out there.
Something gives me the feeling E-ELT will give us the ultimate answer about our universe.
One that hath name thou can not otter
They've narrowed it down to two sites. It's either going on Mauna Kea, or in Chile.
I was just talking to a guy today who works at an 8-meter-class telescope on Mauna Kea, and he was saying that right now, they have proposals for 7 times as many nights as there actually are available. He thought this might drop off a bit once the TMT is built, but I figure hey, the TMT is only one scope, so at most one of those 7 can go use it. The 8-10 meter guys are safe for probably a good while - Keck I is 17 years old this year, and the 30-year-old, 3.6-meter Canada-France-Hawaii telescope is still relevant and doing good work.
Ten years from now, maybe we have a couple 30-40 meter telescopes, but a huge amount of the serious work will still be getting done on stuff 10 meters or smaller.
Village idiot in some extremely smart villages.
The Cosmos TV series by Carl Sagan. I loved that show.
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
They've narrowed it down to two sites. It's either going on Mauna Kea, or in Chile.
and
They haven't decided yet. Either Mauna Kea, Hawaii or Atacama Desert, Chile.
Thanks, guys. The article did not make it apparent, although many big astronomy projects nowadays end up at either site.
It's been a while since I've read about Arizona bagging a major project such as this, same with the Canary Islands. South Africa is sometimes floated around in these articles.
A possibility in my neck of the woods is the San Pedro Mountain Range in Baja California. To make the pitch more plausible, the local state government has begun installing low-glare street lighting in nearby urban areas. The Mexico City based UNAM Astronomy Institute paved 120 kms of road a couple of years ago, from sea level all the way up to the astronomical village.
So you never know where these things could end up.
Lil' Thindime, lilting a lacrimose lament, krashes the kwaint konfines of Kokonino Kounty