First astronomical results from S-Cam

S-Cam is a cryogenic camera for ground-based astronomy based on a 6 x 6 arr ay of Superconducting Tunnel Junctions (STJs). The camera has been designed as a technology demonstrator, aiming to prove the potential of this new ge neration of single photon counting detectors at a ground-based telescope. I n this article we provide an overview of the detector performance, a descri ption of the S-Cam system and a summary of the test results. The first astr onomical data obtained at the William Herschel Telescope (WHT) in La Palma (Canary Islands, Spain) are also described. (C) 2000 Elsevier Science B.V. All rights reserved.