On 19 September 2016, the Council of the Cherenkov Telescope Array Observatory (CTAO) concluded negotiations with the Instituto de Astrofisica de Canarias (IAC) to host CTA's northern hemisphere array at the Roque de los Muchachos Observatory in La Palma, Spain. To provide access to the whole sky, the CTA Observatory will have two sites, with 19 telescopes in the northern hemisphere and 99 in the southern hemisphere planned.

CTA's northern hemisphere site will be located on the existing site of the IAC's Observatorio del Roque de los Muchachos on the island of La Palma, the fifth largest island in the Canary Islands. At 2,200 m altitude and nestled on a plateau below the rim of an extinct volcanic crater, the site currently hosts the two Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes. This location offers excellent conditions for astronomical observations.

"This is a big step, which allows CTAO to start work on the ground," said CTAO gGmbH Managing Director Ulrich Straumann. Rafael Rebolo, Director of the IAC, was very positive about the future: "We are looking forward to a great partnership with CTA and expect exciting discoveries with these telescopes."

The agreement allows the construction of the CTA northern array to proceed at the Roque de los Muchachos site and ensures access to the infrastructure and common services needed for the operation of the observatory, including the digital connection of the CTA network with the rest of the world. In return, Spain will receive 10 percent of the observation time at the northern site, with part of this transferable to the southern hemisphere. Beyond provision of the northern site, Spain plans to make major contributions to the construction of CTA.

"The full sky coverage and excellent conditions provided by the IAC site, together with the ESO site in Chile, are crucial for achieving CTA's ambitious science goals," said CTA Spokesperson Werner Hofmann.

Construction of a Large-Sized Telescope prototype is currently under way on the La Palma site and can be watched live here: http://webcam.lst1.iac.es/stream2view.htm.

Negotiations with the European Southern Observatory (ESO) for the southern hemisphere site near ESO's existing Paranal Observatory in Chile are expected to conclude before the end of 2016. If all goes as planned, construction will begin in 2017, with first telescopes on site in 2018.