Space

All systems go for construction of world's largest optical telescope

All systems go for constructio...
When fully operational, the Giant Magellan Telescope will look further into space and farther back in time than any telescope ever made
When fully operational, the Giant Magellan Telescope will look further into space and farther back in time than any telescope ever made
View 5 Images
The GMT is expected to see further, and resolve better, than any optical instrument ever built
1/5
The GMT is expected to see further, and resolve better, than any optical instrument ever built
The primary mirror is made up of seven separate mirror segments
2/5
The primary mirror is made up of seven separate mirror segments
Of the seven mirrors in the GMT, only one is on the central axis
3/5
Of the seven mirrors in the GMT, only one is on the central axis
When fully operational, the Giant Magellan Telescope will look further into space and farther back in time than any telescope ever made
4/5
When fully operational, the Giant Magellan Telescope will look further into space and farther back in time than any telescope ever made
To be located in the Atacama desert, the GMT will have some of the clearest skies available on Earth
5/5
To be located in the Atacama desert, the GMT will have some of the clearest skies available on Earth
View gallery - 5 images

The construction of the largest optical telescope ever built has moved one step closer today, with US$500 million in funding now committed from 11 international partners. Set to be the world's biggest and most powerful, the Giant Magellan Telescope (GMT) is constructed from seven huge mirrors that will span a total of 25.4-meters (82 ft), bringing in six times more light than any other large telescope. It is also claimed that the instrument will be able to resolve images up to ten times more clearly than the space-based Hubble telescope.

Set to sit high atop a hillside in Chile at the current site of the Las Campanas Observatory above the Atacama desert, the remote location and haze and light pollution free skies will allow the GMT the best chance to employ its incredible imaging capabilities.

With scientific partners including Australia, Brazil, Chile, Korea and the United States, the massive instrument, which will be housed in a 22-story high rotating building, is slated to take its first tentative image of the heavens by 2021 and become fully operational by 2024. At a cost estimated to be around US$1 billion dollars, this enormous eye on the sky has great things expected of it.

Of the seven mirrors in the GMT, only one is on the central axis
Of the seven mirrors in the GMT, only one is on the central axis

"The GMT will herald the beginning of a new era in astronomy," said chair of the Giant Magellan Telescope Organization (GMTO) Board of Directors, Wendy Freedman. "It will reveal the first objects to emit light in the universe, explore the mysteries of dark energy and dark matter, and identify potentially habitable planets in the Earth’s galactic neighborhood."

Consisting of seven separate 8.4-meter (27 ft) diameter segments, to create the combined 25.4-meter (82 ft) primary mirror, each mirror weighs approximately 15,000 kg (17 ton) and needs a year to prepare, cast, and cool. It then takes a further three years or more of meticulous, super-accurate finishing and polishing to produce the required level of accuracy for such a precise instrument.

So accurate, in fact, that the face of the mirror is the same level to within 19 nanometers across its entire surface. As such, if the mirror were expanded to the size of the continental United States, the tallest mountains would be only slightly more more than 1/2 in (12.5 mm) high, according to the mirror lab producing the reflectors at the University of Arizona.

Even though the primarymirrors will be amongst the most accurate ever made, and the skies above theGMT some of the clearest available on Earth, the atmosphere itself still holdsa challenge for this ground-based instrument. Adaptive opticssystems from researchers at the Australian National University (ANU) will helpremove distortions and aberrations caused by the Earth’s atmosphere, such asturbulence, that gives stars their distinctive twinkle.

"The nextgeneration of optical telescopes such as the GMT demand a new class ofastronomical instrumentation and facilities, and the ANU is well equipped tomeet this challenge," said Professor Colless, Director of the Research School of Astronomy and Astrophysics atANU.

The short video below outlinesthis new stage in the development of the GMT.

Source: GMTO, ANU

GMT Construction Phase Begins

View gallery - 5 images
4 comments
DimitarNedev
The European Extremely Large Telescope (E-ELT) will be the world's largest optical telescope [1], set to get first light in 2024 as well. I think that while this is a compelling article, the title and claim are a bit misleading.
[1] https://en.wikipedia.org/wiki/European_Extremely_Large_Telescope
FollowTheFacts
...alright then – now what will be the size of the smallest object that could be seen on the surface of the moon..."ten times better than Hubble" ought to enable detection of "fairly small" objects... ...also, I'd like to see a documentary about the production of this instrument – I'm assuming mirrors won't be spherical, so I'm wondering how the "off-center" segments will be manufactured...
TomGearing
Some answers: 1) Hello FollowTheFacts - here is the full statement on resolution that was 1/3 deleted in this article: "We will have 10 times the collecting area of our current telescopes in Chile and 10 times the angular resolution of the Hubble when working at infrared wavelengths," So unless you have genetically altered your eyes to see infrared wavelengths, you will not get to "see" things on the moon at ten times the resolution. 2) There is a better article in Gizmag dated August 28, 2013, that talks more about manufacturing challenges, with video: http://www.gizmag.com/giant-magellan-telescope/28852/ 3) "Set to sit high atop a hillside in Chile" is this a joke, or does any adult human being think that 13,000 feet elevation is properly described as a "hillside"? 4) Hi DimitarNedev: darn right it is misleading. An honest statement would be "set to be the largest telescope operational in the year 2020, a title it might hold for only 4 years, as the E-ELT will come online in 2024.
Douglas Bennett Rogers
The resolution is 21 ft. on the Moon at the 1/4 wave Rayleigh limit.