Casting Giant Magellan Telescope

Casting Begins For Third Giant Magellan Telescope Mirror

Casting began on Saturday for the third mirror of the Giant Magellan Telescope. The behemoth space-peering object will eventually have seven mirrors and is expected to open in 2020.

The telescope will make its home at the Las Campanas Observatory, about 71 miles north-northwest of La Serena, Chile. The observatory is currently home to the other Magellan telescopes currently in operation.

Two mirrors weighing about 20 tons and measuring about 27 feet in diameter have already been cast, reports The Los Angeles Times. The parabolic mirror is being cast at the University of Arizona’s Steward Observatory Mirror Lab.

It is made up of molten borosilicate, made by the Ohara Corporation, and must be heated up to a scorching 2140 degrees Fahrenheit. Once the initial casting is complete, technicians will spend about one year to polish to within 1/20 the wavelength of light.

When it is completed, the telescope will have an aperture of 80 feet and could provide scientists with photos at a resolution 10 times that of the Hubble Space Telescope.

Space News notes that the Giant Magellan Telescope’s purpose is to detect and characterize exoplanets. It will also investigate the nature of dark matter and dark energy, along with the physics of black holes.

While it’s understandable to think the massive telescope will be the biggest on earth, it’s not. The planned Thirty Meter telescope, which will be constructed on Mauna Kea in Hawaii, will be about 98 feet across. The European Extremely Large Telescope project will have a main mirror 138 feet across. Also placed in Chile, it will hold the record for the largest Earth-based optical telescope.

The new telescope’s first mirror has been completed and the second has been cast, but still needs to be polished. While work on the mirrors continues, the Giant Magellan Telescope’s home is also being prepared. Workers made the first blasts on the mountain top last year and will begin construction of the GMT’s facility in 2014.

[Image via Giant Magellan Telescope – GMTO Corporation]