Translator Disclaimer
Paper
7 July 2004 Concept for a second Giant Magellan Telescope (GMT) in Antarctica
Author Affiliations +
Proceedings Volume 5382, Second Backaskog Workshop on Extremely Large Telescopes; (2004) https://doi.org/10.1117/12.566107
Event: Second Backaskog Workshop on Extremely Large Telescopes, 2003, Backaskog, Sweden
Abstract
While definitive winter measurements for Dome C must await until 2004, on the basis of existing data the Antarctic Dome sites promise the best conditions on the Earth for many astronomical observations. Because atmospheric turbulence is largely confined to an ~ 100 m ground layer, adaptive correction with a single deformable mirror conjugated to this layer should yield an 8-arcminute field of view with 0.1 arcsec images at optical wavelengths. The ground layer wavefront aberration can likely be sensed with natural guide stars found over the wide field. In the infrared there is the added advantage of low thermal background from the cold atmosphere and telescope optics, as much as 50x reduction in the 3.5 μm L band. An ELT that fully exploited these advantages would provide a uniquely powerful ground-based complement to the James Webb Space Telescope, especially for spectroscopy. We consider here the concept of building a copy of the 21 m Giant Magellan telescope (GMT) telescope (Johns, 2003) at Dome C. The optical design is ideal, with a very fast (f/0.7) primary mirror and direct Gregorian focus formed by a deformable secondary conjugated to the ground layer. In the thermal infrared, diffraction-limited images are produced with the low background of only two warm mirrors, the primary and secondary. There are also practical advantages. The enclosure is of modest size, by ELT standards, because the primary is very fast. Assembly, debugging and maintenance problems on-site are minimized by a primary mirror built from a small number of large, pre-tested segments. By building a copy of an already implemented ELT, engineering difficulties will be minimized, and experienced support staff will be available at the first GMT, where also instruments can be pre-tested.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
James Roger P. Angel, Jon S. Lawrence, and John W.V. Storey "Concept for a second Giant Magellan Telescope (GMT) in Antarctica", Proc. SPIE 5382, Second Backaskog Workshop on Extremely Large Telescopes, (7 July 2004); https://doi.org/10.1117/12.566107
PROCEEDINGS
9 PAGES


SHARE
Advertisement
Advertisement
RELATED CONTENT

The E-ELT program status
Proceedings of SPIE (July 27 2016)
Infrared optimized AO system for a 15 to 20...
Proceedings of SPIE (February 04 2003)
Mirror requirements for SAFIR
Proceedings of SPIE (October 12 2004)
Buyer's guide to telescopes at the best sites Dome...
Proceedings of SPIE (October 12 2004)

Back to Top