Free Astronomy Magazine March-April 2019

20 MARCH-APRIL 2019 SPACE CHRONICLES C TA won't be detecting gamma rays directly. It will pick up Cherenkov light, the blue flash of light resulting from gamma rays interacting with the Earth's atmosphere. [CTAO/ESO] With these three agreements in place, the CTAO will be able to begin construction on the southern site. The Instituto de Astrofisica de Canarias will host CTA’s northern hemisphere array at the Observato- rio del Roque de los Muchachos on the island of La Palma, Spain. Con- struction of both the northern and southern arrays is expected to begin in 2020. “Operating CTA at Paranal will open a new window on the Uni- verse for astronomers in the ESO Member States, Chile, and world- wide,” commented ESO’s Director General, Xavier Barcons. “ESO’s rich experience of maintaining and op- erating fleets of telescopes in re- mote areas will be invaluable for the CTA project.” The southern site of CTA is only 11 kilometres southeast of the location of the Very Large Telescope at ESO's Paranal Observatory in the Atacama Desert, and only 16 kilometres from the construction site of the upcom- ing Extremely Large Telescope. This is one of the driest and most iso- lated regions on Earth — an astro- nomical paradise. In addition to the ideal conditions for year-round ob- servation, installing CTA at the Paranal Observatory provides it with the advantages of ESO’s infrastruc- ture. The existing infrastructures and facilities, and ESO’s long-lasting experience spearheading interna- tional astronomical projects in Chile, will all support the construction and operation of the new telescope array. “Thanks to the agreements signed today, the CTAO will not only bene- fit from Chile's spectacular night sky but also from ESO's facilities and deep experience, which will be an invaluable contribution to the real- isation of this ambitious system of telescopes,” said Federico Ferrini. “The partnership between ESO and the CTAO will serve as the corner-