Using the photons from the Crab nebula seen by GLAST to calibrate MAGIC and the imaging air Cerenkov telescopes.

In this article we discuss the possibility of using the observations by GLAST of standard gamma sources, as the Crab Nebula, to calibrate imaging air Cherenkov detectors, MAGIC in particular, and optimise their energy resolution. We show that at around 100 GeV the absolute energy calibration uncertainty of Cherenkov telescopes can be reduced to less than or similar to 10% by means of such cross-calibration procedure.(c) 2005 Elsevier B.V. All rights reserved.