Whole‐sky patrol with 7kx4k‐CCD chips

Since the twenties of the last century Sonneberg Observatory runs in each clear night a photographic sky patrol with a system of small telescopes reaching 14m in the blue and 13m in the yellow-red. Currently much effort is made to take over this photographic sky patrol by a system of electronic detectors. Owing to the fact that wide-field systems need either large CCDs or arrays of CCDs in order to cover the whole field of view, the technical availability of large detectors was one of the central problems in the past. We now introduce the use of a PHILIPS 7k × 4k chip in wide-field astronomy for our whole-sky patrol. Although the chip has a quantum efficiency of only about 30%, its big size (12μm pixel size) of 48 × 84 mm offers, for the first time, the replacement of large photographic plates by a single CCD chip. We report our first experiences with this chip when using it with a fish-eye lens for whole-sky imaging. An integration of five minutes reaches down to approximately 9m and enables the investigation of different targets such as variable stars, meteors, GRB counterparts, a.s.o..