  The CAT imaging telesope, which uses the Atmospheric Cherenkov Technique to
observe TeV gamma-ray sources, has been operating since September 1996. Located
in southern France, it features a fine grained camera consisting of 546 PMT
with a pixel size of 0.12 degrees. Strong gamma-ray signals from Mkn 501 above
200 GeV were detected during observations made in April 1997. The high
signal/noise ratio for these data enables direct characterization of the
gamma-ray images as recorded in the camera. These results are used to validate
the Monte-Carlo simulations of the response of the telescope to gamma-ray
showers and to improve its performances. Observational results on Mkn 180 and
the Crab nebula spectrum are presented.
