For several years the only experiments sensitive to astrophysical gamma rays with energies beyond the reach of EGRET but below that of the Cherenkov imaging telescopes have been the ”solar tower” detectors. They use > 2000 m mirror areas to sample the Cherenkov wavefront generated by < 100 GeV gamma rays, obtaining Crab sensitivities of more than 6σ in one ON-source hour. I will review the hist...
