15 October 2005 Launch telescope for astronomical adaptive optics
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The Launch Telescope Assembly (LTA) consists of a 50 cm class beam expander (angular magnification 12.5x) and it is an essential subsystem of Laser Guide Star Facility (LGSF), which provides an artificial reference star for adaptive compensation of atmospheric turbulence for one of the VLT (Very Large Telescope) 8-meters telescopes of ESO (European Southern Observatory). LTA is an afocal system, with parabolic primary and secondary mirrors, a flat 45° tertiary mirror and an exit window. It is fed with collimated Sodium laser beam, expanding and directing it along the line of sight of the 8-m telescope. Resonance backscatter from atmospheric Sodium layer at about 90 km altitude produces a point like artificial source at this altitude. The high optical quality requested for very fast optics, the severe constraints of the layout accommodation and the mass reduction made LTA a technological challenge that Galileo Avionica has been able to design, realise, align and test as requested. LTA will be positioned atop the secondary mirror unit of one of the four VLTs.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alberto Caruso, Alberto Caruso, Andrea Novi, Andrea Novi, Giuseppe Basile, Giuseppe Basile, } "Launch telescope for astronomical adaptive optics", Proc. SPIE 5962, Optical Design and Engineering II, 596224 (15 October 2005); doi: 10.1117/12.625091; https://doi.org/10.1117/12.625091


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