Large field-of-view configurations for large-telescope adaptive optics systems: advantages and tradeoffs

Abstract

In order to achieve high sky coverage with natural guide star adaptive optics systems, the reference stars need to be chosen over a large field of view. But the size of the optical beam can become unmanageably large in current and planned future giant telescopes. This can render the optics unaffordable. To solve this issue, we have adopted two approaches - multiple fields of view and star-enlargers - for the LINC-NIRVANA layer-oriented, multiple-conjugated adaptive optics system. In this paper, we compare and contrast the advantages and disadvantages of various optical configurations for wide-field, natural guide star acquisition on current 8-meter and future 25-40 meter extremely large telescopes.