Adaptive Optics for Small Aperture Telescopes

Adaptive Optics (AO) is one of the techniques to reduce aberrations caused byatmosphere turbulence in the light coming from objects above this layer thatreaches ground based optical telescopes. It was proposed 62 years ago, andsince then it has undergone a fast evolution due to the technical developmentsin mechanics, optics and electronics. Due to these advances and the efforts ofthe research community, AO nowadays is widely used in big and moderate sizetelescopes and it has become an essential instrument in this telescope segment.The research for its use in small aperture telescopes has been limited for differentfactors: it is an expensive technique; small aperture involves less gathered lightthat could reduce AO performance; and also low altitudes where usually thesetelescopes are located result in severe aberrations. This research has been focused inthe investigation of new techniques and procedures that facilitate the engineeringof an AO system for small aperture telescopes.For this purpose an AO testbed has been developed, which includes a portableopto-mechanical platform adapted specifically for its use in small aperturetelescopes, which has been tested in laboratory and assessed with on-skyexperiments.In this research, an original AO real time processing control architecture hasbeen defined, that can be fully implemented in a low cost standalone FieldProgrammable Gate Array (FPGA) device, unlike standard AO configurations,which typically rely in complex distributed hardware architectures which makethe system more expensive and less portable.The lack of gathered light inherent to small aperture telescopes constitutes asevere limitation for an AO system. Hence is crucial to develop optimizedimage processing algorithms that balance this drawback. Here a novel fastimplementation of a centroiding algorithm has been accomplished, adapted tosevere low light conditions, and from this a closed loop AO system has beendemonstrated.There is wide potential demand in the scientific and amateur astronomycommunity in this field, and the innovations and engineering concepts introducedhere constitute a valid and proven AO system applied for small aperture telescopes