The partners building the world’s largest and most advanced optical telescope at Mauna Kea’s summit have signed an agreement laying the foundation for the telescope’s operation.

The Thirty Meter Telescope project said today representatives from partnering institutions in the U.S., Canada, China, India and Japan signed the document.

The agreement defines project goals, member party rights, obligations and benefits. It also establishes a governance structure.

Construction will begin next April. Scientific operations on Mauna Kea are expected to start in 2022.

The telescope is a partnership of the Association of Canadian Universities for Research in Astronomy, the California Institute of Technology, the National Astronomical Observatory of Japan, institutions in India, a consortium of Chinese institutions and the University of California.