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Proceedings Paper

Multi-laser-guided adaptive optics for the Large Binocular Telescope
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Paper Abstract

We describe the conceptual design of an advanced laser guide star facility (LGSF) for the Large Binocular Telescope (LBT), to be built in collaboration with the LBT's international partners. The highest priority goal for the facility is the correction of ground-layer turbulence, providing partial seeing compensation in the near IR bands over a 4' field. In the H band, GLAO is projected to improve the median seeing from 0.55" to 0.2". The new facility will build on the LBT's natural guide star AO system, integrated into the telescope with correction by adaptive secondary mirrors, and will draw on Arizona's experience in the construction of the first multi-laser adaptive optics (AO) system at the 6.5 m MMT. The LGSF will use four Rayleigh beacons at 532 nm, projected to an altitude of 25 km, on each of the two 8.4 m component telescopes. Initial use of the system for ground layer correction will deliver image quality well matched to the LBT's two LUCIFER near IR instruments. They will be used for direct imaging over a 4'×4' field and will offer a unique capability in high resolution multi-object spectroscopy. The LGSF is designed to include long-term upgrade paths. Coherent imaging at the combined focus of the two apertures will be exploited by the LBT Interferometer in the thermal IR. Using the same launch optics, an axial sodium or Rayleigh beacon can be added to each constellation, for tomographic wavefront reconstruction and diffraction limited imaging over the usual isoplanatic patch. In the longer term, a second DM conjugated to high altitude is foreseen for the LBT's LINC-NIRVANA instrument, which would extend the coherent diffraction-limited field to an arcminute in diameter with multi-conjugate AO.

Paper Details

Date Published: 24 September 2007
PDF: 14 pages
Proc. SPIE 6691, Astronomical Adaptive Optics Systems and Applications III, 66910O (24 September 2007); doi: 10.1117/12.734821
Show Author Affiliations
M. Lloyd-Hart, Steward Observatory, Univ. of Arizona (United States)
R. Angel, LBT Observatory (United States)
R. Green, MMT Observatory (United States)
T. Stalcup, The Univ. of Arizona (United States)
N. M. Milton, Steward Observatory, Univ. of Arizona (United States)
K. Powell, Steward Observatory, Univ. of Arizona (United States)

Published in SPIE Proceedings Vol. 6691:
Astronomical Adaptive Optics Systems and Applications III
Robert K. Tyson; Michael Lloyd-Hart, Editor(s)

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