  A new primary mass independent method of energy measurement has been
developed by exploiting: a) the joint analysis of the shower size, obtained by
EAS-TOP, and of the EAS atmospheric Cherenkov light lateral distribution,
obtained by the QUEST array, and b) simulations based on the CORSIKA/QGSJET
code. The method is based on the correlation between the size/energy ratio and
the steepness of Cherenkov light lateral distribution and has been compared
with a "classical" one based on the Cherenkov light flux at a fixed distance
(175 m) from the EAS core. An absolute energy calibration of the EAS
atmospheric Cherenkov light flux has been obtained.
