Giant Magellan Telescope

The Giant Magellan Telescope ( GMT) is a planned giant telescope in the highlands of Chile, which is to be completed in 2022. After his accurate calibration, it is said to have up to ten times better resolution ( selectivity ) as the Hubble Space Telescope. His name can be the " relationship " with the two Magellan telescopes of the Las Campanas Chilean Observatory resonate.

Planning

It should consist with 8.4 m diameter after completion of 7 primary mirrors. A central mirror having a central opening for the Cassegrain focus, and the remaining 6 are closely mounted peripherally, all of which are mounted on a common azimuthal mount. The result is a telescope with an effective mirror diameter of 21.4 m ( surface ), and 24.5 m (resolution). As model for this design, the Large Binocular Telescope applies (with two such mirrors ) on Mt Graham in the U.S. state of Arizona. The focal length of the primary mirror is 18 m for such a device is extremely short ( f / 0.7 ), which allows a very compact design. (For comparison: The primary mirror of the Hale telescope at Palomar Observatory has with his 5-m mirror 17 m focal length. ) The effective focal length of the entire system is 203 m ( f / 8.0). In the optical design is aplanatic Gregory telescope. The size of vignetting image field should be 26 minutes of arc. (For comparison, the apparent diameter of the full moon is about 30 arc minutes. )

Main proponents for the GMT is the American Roger Angel, the founder of the mirror Laboratory of Steward Observatory of the University of Arizona. This laboratory has - together with Schott & Gen.. Mainz - Experience in the cast of "light " giant mirror with the help of rotating furnaces. The rotation creates already a parabolic mirror surface during casting and significantly reduces the subsequent grinding effort. While the bulkhead mirror thin, deformable menisci (such as the Very Large Telescope ), the mirror of the abovementioned laboratories are rigid, with a honeycomb design on the back, which is poured together with the mirror from Japanese borosilicate glass (type E6 of Ohara ).

Special

The new thing GMT is also from the above-mentioned Labor incurred grinding and polishing of the six peripheral primary mirror, because this must be asymmetric. The sponsors have initially released by the estimated 400 to 500 million U.S. dollars total cost 20 million for the production and testing of an asymmetric primary mirror and the associated secondary mirror. The primary mirror is being polished. In addition to a 1:5 model of the optics is studied.

To achieve the best possible resolution ( λ / D = 600 nm/24, 5 m ⇒ 0.005 arc seconds, ten times better than the Hubble Space Telescope ) will the seven thin deformable secondary mirror of about 1 m in diameter adaptive optics.

The relatively compact at the intended focal length design of the dome required is only slightly larger than that of the Palomar Observatory. As a location for the telescope is currently the Las Campanas Observatory, near the VLT favored in the Chilean Andes.

Organization

The members of the Giant Magellan Telescope Organization ( GMTO ) are:

Completion

The contract for the construction was concluded in February 2009. Completion is scheduled for 2022Vorlage: Future / planned in 5 years. For a first, 2005 at the University of Arizona Mirror Lab cast primary mirrors 2012 polish and testing were completed in October. Of the estimated costs of $ 700 million 130 million already pledged. The blank of the second mirror was completed on 14 January 2012 23 March 2012 was started with the blasting work at the telescope site to create a flat building site.

Cassegrain reflector Minute of arc Schott AG Parabolic reflector Paranal Observatory University of Texas at Austin
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