Author/Authors :
Cornils، نويسنده , , R. and Gillessen، نويسنده , , S. and Jung، نويسنده , , I. and Hofmann، نويسنده , , W. and Beilicke، نويسنده , , M. and Bernlِhr، نويسنده , , K. and Carrol، نويسنده , , O. and Elfahem، نويسنده , , S. and Heinzelmann، نويسنده , , G. and Hermann، نويسنده , , G. and Horns، نويسنده , , D. and Kankanyan، نويسنده , , R. and Katona، نويسنده , , A. and Krawczynski، نويسنده , , H. and Panter، نويسنده , , M. and Rayner، نويسنده , , S. and Rowell، نويسنده , , G. and Tluczykont، نويسنده , , M. and van Staa، نويسنده , , R.، نويسنده ,
Abstract :
Mirror facets of the high energy stereoscopic system imaging atmospheric Cherenkov telescopes are aligned using stars imaged onto the closed lid of the photomultiplier camera, viewed by a CCD camera. The alignment procedure works reliably and includes the automatic analysis of CCD images and control of the facet alignment actuators. On-axis, 80% of the reflected light is contained in a circle of less than 1 mrad diameter. The spot widens with increasing angle to the telescope axis. In accordance with simulations, the spot size has roughly doubled at an angle of 1.4° from the axis. The expected variation of spot size with elevation due to deformations of the support structure is visible, but is completely non-critical over the usual working range. Overall, the optical quality of the telescope exceeds the specifications.
