  Cherenkov telescopes are also sensitive to the atmospheric fluorescence
produced by the extensive air showers. However this contribution is neglected
by the reconstruction algorithms of imaging air Cherenkov telescopes IACTs and
wide-angle Cherenkov detectors WACDs. In this paper we evaluate the
fluorescence contamination in the Cherenkov signals from MC simulations in both
kinds of Cherenkov telescopes and for some typical observational situations.
Results for an observation level of 2200 m a.s.l. are shown. In addition, the
feasibility and capabilities of IACTs working as fluorescence telescopes are
discussed with the assistance of some geometrical calculations.
