Recent topics of terrestrial observatories

Ground based observatories in high energy astro-particle physics are used to explore the non-thermal high energy Universe. These detectors provide data to advance our understanding of cosmic accelerators of cosmic rays, gamma rays and neutrinos up to energies of 1E15 eV. The detection principle is in most cases based on shower detection, mostly using photodetectors. This report gives an overview of new techniques in ground based gamma astronomy, cosmic ray air shower arrays and large under water/ice neutrino observatories.