2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/204796Magic Telescope may observe and reveal at horizons lights from air-shower Cherenkov reflections. The ground, the sea, the cloudy sky (below the mountain) may reflect PeVs-EeV UHECR Cherenkov lights observable by MAGIC telescopes. Even rarest UHE neutrino skimming the atmosphere or skimming the Earth may induce upward-horizontal airshowers: a new Neutrino Astronomy. These fluorescence signals or the Cherenkov reflections in upper cloudy sky may flash in correlated BL-Lac or GRB shining at opposite edges. Geomagnetic splitting of Horizontal Air-showers may offer a new spectroscopy of UHECR from the knee up to GZK energy edges.4 pages, 4 figures, HEP 2007: The 2007 Europhysics Conference on High Energy PhysicsAstrophysicsReflecting on Cherenkov reflectionstext