Gamma-ray telescopes .28less than 0.01 nm.29 History of the telescope

gamma rays absorbed high in earth s atmosphere gamma-ray astronomy conducted satellites. gamma-ray telescopes use scintillation counters, spark chambers , more recently, solid-state detectors. angular resolution of these devices typically poor. there balloon-borne experiments in 1960s, gamma-ray astronomy began launch of oso 3 satellite in 1967; first dedicated gamma-ray satellites sas b (1972) , cos b (1975). compton gamma ray observatory (1991) big improvement on previous surveys. high-energy gamma-rays (above 200 gev) can detected ground via cerenkov radiation produced passage of gamma-rays in earth s atmosphere. several cerenkov imaging telescopes have been built around world including: hegra (1987), stacee (2001), hess (2003), , magic (2004).