The design and construction of the 30 m2 Bicentennial Gamma Ray Telescope at Woomera South Australia is described. This novel instrument is now completed and commissioning is underway. It is designed to observe astronomical sources at energies greater than ∼ 500 GeV by means of atmospheric Cerenkov light. It contains 55 spherical, glass mirrors of focal length 2.66 m arranged in three groups of 10 m2, to focus the light onto three sets of detectors operated in fast co-incidence. The recording electronics includes a rubidium clock to enable pulsars to be studied.