imaging telescope, equipped with a very-high-deÞnition camera (546 fast
phototubes with 0.12¡spacing surrounded by 54 larger tubes in two guard rings) started operation in Autumn 1996 on
the site of the former solar plant The« mis (France). Using the atmospheric Cherenkov technique, it detects and identiÞes very
high energy c-rays in the range 250 GeV to a few tens of TeV. The instrument, which has detected three sources (Crab
nebula, Markarian 421 and Markarian 501), is described in detail. ( 1998 Elsevier Science B.V. All rights reserved.
Keywords: Gamma-ray astronomy; Atmospheric Cherenkov detect