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Proceedings Paper

GLAS: launching Rayleigh lasers from the WHT
Author(s): Paul Jolley; Tom Gregory
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Paper Abstract

The 4.2m William Herschel Telescope (WHT) at the Isaac Newton Group of Telescopes (ING) is due to have a new Rayleigh laser beacon installed. This will form part of the Ground-layer Laser Adaptive optic System (GLAS). GLAS will compliment the existing Nasmyth Adaptive Optic Multipurpose Instrument (NAOMI) currently in operation and allow for much greater sky coverage than before. A 30W laser will be launched from behind the secondary mirror of the WHT. To facilitate this, a support has been designed to mount the laser on the top end ring of the telescope. The mount is designed to give a gravity stable platform in a thermally stable environment. The mount required the use of astatic levers to help maintain alignment with the telescope. The laser beam is steered over the telescope vanes and into the Beam Launch Telescope (BLT) which is mounted behind the secondary mirror. The BLT then expands the beam and launches it to 20Km. Two wavefront sensors are used to correct the image. The laser guide star wavefront sensor (LGS WFS) uses a beamsplitter to pickoff the laser return at its wavelength. The existing NAOMI WFS is still used but is now the natural guide star wavefront sensor (NGS WFS) and corrects for tip/tilt. This paper will concentrate on describing the mechanical design and FEA of the laser up launch system (laser cradle and mount and the BLT). A very brief overview of the LGS WFS will be given for system completeness.

Paper Details

Date Published: 28 June 2006
PDF: 11 pages
Proc. SPIE 6272, Advances in Adaptive Optics II, 62723P (28 June 2006); doi: 10.1117/12.670789
Show Author Affiliations
Paul Jolley, Isaac Newton Group of Telescopes (Spain)
Tom Gregory, Isaac Newton Group of Telescopes (Spain)

Published in SPIE Proceedings Vol. 6272:
Advances in Adaptive Optics II
Brent L. Ellerbroek; Domenico Bonaccini Calia, Editor(s)

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