  Powerful nanosecond light sources based on LEDs have been developed for use
in astroparticle physics experiments. The light sources use either matrixes of
ultra bright blue LEDs or a new generation high power blue LEDs. It's shown
that such light sources have light yield of up to 10**10 - 10**12 photons per
pulse with very fast light emission kinetics. The described light sources are
important for use in calibration systems of Cherenkov and scintillator
detectors. The developed light sources are currently used successfully in a
number of astroparticle experiments, namely: the TUNKA EAS experiment, the
Baikal neutrino experiment etc.
