  The CELESTE experiment uses the heliostats of an old solar farm in the French
Pyrenees to detect gamma ray air showers by the atmospheric Cerenkov technique.
Observations of the TeV blazar Markarian 421 have been made with the fully
instrumented CELESTE experiment since December 1999. The detection of gamma ray
emission from this source at energies greater than 50 GeV is presented here. A
comparison is made with the light curve from the CAT experiment at the same
site which shows correlation between the observed gamma ray fluxes and the
detection of short duration flaring episodes.
