An international project to build two observatories to detect very high-energy gamma rays (20 GeV to 300 TeV), one in the northern hemisphere at the Roque de los Muchachos Observatory and the other on Cerro Armazones in Chile, near the Paranal Observatory. The arrays contain three sizes of telescope: small, 4-m aperture, to detect the highest energies, up to 300 TeV; medium, 12-m aperture (energies 100 GeV to 10 TeV); and large, 23-m aperture (low energies, 20–200 GeV). The southern array will have a core of four large telescopes surrounded by 25 medium and 70 small ones, giving a total of 99. The northern array will also have four large telescopes but only 15 medium and no small ones; hence it cannot detect the highest energies. Both arrays are expected to come into operation in the early 2020s. The CTA’s headquarters are in Bologna, Italy, and its Science Data Management Centre is at Zeuthen, near Berlin.

https://www.cta-observatory.org/ Cherenkov Telescope Array official website.