Cosmic Rays Astrophysics and Neutrino Astronomy beyond and beneath the   Horizons
  Modern Terrestrial Cerenkov Telescopes and Array Scintillators facing the Horizons may soon reveal far Cosmic Rays or nearer PeVs-EeVs Neutrino Showers Astronomy. Indeed UHE neutrino interactions in air, leading to Horizontal Showers, may take place through several channels: the main Glashow resonant one, the charged nuclear interactions and the neutral current events. Analogous events occur also for the neutrino-nucleon events.   These interactions are producing hadronic or electromagnetic showers at the far horizons and their correlated secondaries Cerenkov flashes. Comparable interactions are producing, inside the Earth, the Horizontal, but Up-going ultra-relativistic tau, whose decay in flight is source of tau Air Showers (Uptaus and HorTaus); Horizontal Tau Air-Showers are rarely (one-two order of magnitude) enhanced by highest mountain chains at horizons, as in AUGER experimental site; their hadronic or electromagnetic traces are preferentially at PeV-EeV energies; their tracks are amplified by their muon-gamma bundles whose signals are above the random noises and better disentangled by Cerenkov flashes in time coincidence. More exotic UHE SUSY interactions at tens PeVs-EeV energy may blaze at Horizons. Anyway common High Energy Cosmic rays at PeVs-EeVs energy must traces their presence in Magic-like Cerenkov Telescopes at horizons. Present Magic Telescopes facing the Horizons are, at equal given time, almost comparable with the Amanda underground neutrino detector. 
D. Fargion