The Advanced Technology Solar Telescope (ATST) is being built by a collaboration of twenty-two institutions led by the U.S. National Solar Observatory. It will be located at the Haleakala High Altitude Observatory on the island of Maui in Hawaii. Construction at the telescope site began in late 2012. When completed, it will be the world’s most powerful solar telescope, able to study features on the Sun and its corona as small as eighteen miles (thirty kilometers) across.