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World's Largest Telescope Begins Production
JohnnyNapalm writes "The Aggie Daily News is reporting today that the first mirrors have been cast for the world's largest telescope. The result of cooperation from some of the foremost institutions in education and science in the nation, the Giant Magellan Telescope stands to operate at a resolution 10 times larger than the Hubble. The project, set to be constructed in Chile, is slated for completion in 2016."
Am I alone in feeling that we haven't even used hubble to the fullest extent of its abilities? Not sure why this is a priority right now.
Largest ptical telescope, perhaps. Arecibo Observatory is still the biggest single telescope, though there are even larger arrays.
After all, I am strangely colored.
Will it be able to show the moon landings?
Photos
yes, but with adaptive optics and reprocessing the difference is not as big, and the operating costs are nowhere close, and if they add enough additional capabilities (can't do ir/uv in atmosphere, but some radio could help) it might be useful. Few earth telescopes will ever rival hubble however, the enormous field of view coupled with the amazing contrast allowed by its orbit really can't be matched on earth, at least not without additional processing.
for actual scientific purposes, and not pretty pictures it should be as useful.
The first rule of USENET is you do not talk about USENET.
It does use adaptive optics. Have a peek at the tech section of the GMT site, here: http://www.gmto.org/tech_overview>
From the aforementioned link: The GMT secondary mirror is composed of seven thin adaptive shells, with each segment mapping to a single primary mirror segment. The adaptive secondary will provide diffraction-limited performance over modest fields of view and ground-layer adaptive optics over a field of ten to twenty arcminutes in diameter.
-scott
My other sig is a Glock
Price of putting the 2.5-meter Hubble Space Telescope in orbit, and installing its corrective glasses:
:)
Somewhere on the order of $2-4 Billion.
Price of building both 10-meter Keck Telescopes on Mauna Kea:
About $200 Million.
Soooo... for the cost of one orbiting telescope (and that wasn't even counting the later servicing missions), you could build 20-40 terrestrial telescopes, each with four times the diameter.
Oh, and as a data point... expected price of building the 30-meter Telescope:
About $1 Billion.
Launching stuff is way more expensive than getting it places on boats or trucks.
Village idiot in some extremely smart villages.
For something a little closer to completion than 2016, check out the Southern African Large Telescope. Scheduled to open in November, and will be the biggest optical telescope in the southern hemisphere.
Regards,
-Jeremy
I had the wonderful experience of being an undergraduate in astrophysics at UC Santa Cruz, where a grant in adaptive optics was paving the way for ground-based telescopes. By shining a laser straight where the telescope is pointed, aberrations and distortions from the atmosphere can be measured and exactly countered by the telescope, effectively cancelling atmospheric effects to a remarkable degree. Check out http://cfao.ucolick.org./ The main telescope was outside of San Jose, CA, which might seem a strange location for a telescope due to its proximity to a large city. But since all of the streetlamps in San Jose are sodium (whose spectral properties are well known and simple), those features can be subtracted from any measured spectra and in conjunction with adaptive optics, the telescope outside northern california's largest city produces world-class astronomy. This telescope being built should be pretty neat. I wonder how they will deal with gravitational aberrations. Plus scientists won't ever need to face the threat of government letting their instrument "deorbit" while still producing good data.
I can't think of many non-military organisations which have bigger budgets
I can. 2005 Numbers:
Department of Health & Human Services: 584B
Department of Education: 56.5B
Department of Veterans Affairs: 32.5B
Department of Housing & Urban Development: 32B
Department of Homeland Security: 29B
Department of State: 27.5B
Department of Energy: 23.8B
Department of Agriculture: 21.4B
Department of Justice: 20.2B
NASA: 16.1B
Cheaper Departments include: Treasury, Transportation, Labor, Interior, Drug Administration, EPA, and Commerce. They generally run 8-15 billion each.
Source: Washington Post
I don't read AC A human right
It's one piece of glass, with a single, smooth surface on the front, 8.4 m in diameter. The hexagonal "pieces" are holes on the backside. It basically looks like a big honeycomb. This design gives you great stiffness and strength, with only 20% the weight that a solid mirror would have.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.
The Steward Observatory Mirror Lab had an open house yesterday for observatory personnel, which I attended.
The spin-cast oven is huge. In these pictures, you only see the top portion of it, it actually fills the floor below as well. I believe this is the only large spin-cast mirror facility in the world. The idea behind spin-casting is that, by spinning the molten glass as it is slowly cooled, you automatically get a paraboloid top surface. This makes the final shaping of the mirror much easier, since the first-order shape is already there.
Actually, in the case of the GMT, it will use seven mirrors, six of which are off-axis. The off-axis mirrors will obviously have a more complicated surface than a typical on-axis paraboloid. The mirror being cast now is an off-axis mirror; it is a proof-of-concept that they can grind an eight-meter chunk of glass to an off-axis paraboloid shape with a surface RMS of 20 nanometers (!).
In a few months when the mirror has cooled and solidified, it will be removed from the oven, cleaned, ground, and eventually, polished. The stress-lap polisher is very impressive. It has a network of stress actuators above it, which can dynamically change the shape of the polisher's surface as it travels across the mirror.
It's interesting that the "Aggie Daily News" was chosen as the linked story, which makes it sound like UT Austin and Texas A&M are the major players in the GMT, along with a handful of other, unnamed institutions. In fact, the Carnegie Institute is the impetus behind the project, and the U of Arizona is providing the mirrors. I think this UA News article is much more informative.
Liberal (adj.): Free from bigotry; open to progress; tolerant of others.