Arxiv:1605.06277V1 [Astro-Ph.IM] 20 May 2016
Bokeh Mirror Alignment for Cherenkov Telescopes M. L. Ahnena, D. Baackd, M. Balbob, M. Bergmannc, A. Bilanda, M. Blankc, T. Bretza, K. A. Bruegged, J. Bussd, M. Domked, D. Dornerc, S. Einecked, C. Hempflingc, D. Hildebranda, G. Hughesa, W. Lustermanna, K. Mannheimc, S. A. Muellera,, D. Neisea, A. Neronovb, M. Noethed, A.-K. Overkempingd, A. Paravacc, F. Paussa, W. Rhoded, A. Shuklaa, F. Temmed, J. Thaeled, S. Toscanob, P. Voglera, R. Walterb, A. Wilbertc aETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich, Switzerland bUniversity of Geneva, ISDC Data Center for Astrophysics Chemin d'Ecogia 16, 1290 Versoix, Switzerland cUniversit¨atW¨urzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 W¨urzburg, Germany dTU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund, Germany Abstract Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emit- ted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment remains a challenge. Here we present a simple, yet extendable method, to align a segmented reflector using its Bokeh. Bokeh alignment does not need a star or good weather nights but can be done even during daytime. Bokeh alignment optimizes the facet orientations by com- paring the segmented reflectors Bokeh to a predefined template. The optimal Bokeh template is highly constricted by the reflector’s aperture and is easy ac- cessible.
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