Observing Gamma Universe from Namibia

Located on Khomas Highland of Namibia is an array of large Gamma ray detectors known as HESS or High Energy Stereoscopic System. The acronym was chosen in honor of Victor Hess, who was the first to observe cosmic rays. HESS has five telescopes, four with a mirror just under 12 m in diameter, arranged 120 m apart from each other in a square, and one larger central telescope with a 28 m mirror. Since the gamma rays are blocked by our atmosphere (thankfully!) the array indirectly observe the cosmic gamma sources by detecting brief flashes of optical light, called Cherenkov light.