Neutrino Astronomy beyond and beneath the Horizons
  The Earth's Shadow to Cosmic Rays offer a windows to Tau Neutrino Astronomy at the Horizon edges. Inclined and Horizontal C.R. Showers (70^o-90^o zenith angle) produce secondary (gamma,e) mostly suppressed by high column atmosphere depth. The shower Cherenkov photons are diluted and filtered by air opacity, but secondary penetrating, muon pairs and their decay into electron pairs, revive additional Cerenkov flash lights. Most largest GeVs gamma telescopes may detect such UHECR horizontal showers. Arrival angle and column depth, shower shape, timing may inform on the altitude interaction and on primary UHECR composition. At larger zenith angle (90^o-99^o) more rare up-going showers are traced by muon (as well electromagnetic) bundles that would give evidence of rare Earth-Skimming neutrinos, tau and anti-tau neutrinos, at PeVs-EeVs energies. Their rate may be comparable with 6.3 PeVs anti-neutrino electron induced air-shower originated in interposed atmosphere, by W^- resonance at Glashow peak. Additional and complementary UHE SUSY neutralino or staus may blaze. Their nature might be disentangled by Stereoscopic Telescopes array. Magic and Hess telescope in present set up may be already comparable to AMANDA underground neutrino detector. Such telescopes pointing at the horizons toward active sources (AGN,BL Lac Objects, GRBs or SGRs blazing micro-quasar jet, and SNRs) do experience in those directions an air mass corresponding to a km^3 water one. Therefore Horizontal Showering is already the most sensitive windows to Neutrino Astronomy possibly pointing to AGN,GRB or SGR events. 
D. Fargion