The Honolulu Advertiser reports that a deal has been finalized to build on Maui’s Haleakala the second most expensive telescope in the world. The $161 million Advanced Technology Solar Telescope will be the world’s largest optical solar telescope and was developed by the U.S. Solar Research Observatory. The $300 million Subaru telescope on Mauna Kea is on the most expensive. In addition to the Mees Solar Observatory, the Haleakala summit is home to the Air Force’s Advanced Electro-Optical System telescope; Japan’s 80-inch MAGNUM Telescope; the 80-inch Faulkes Telescope, devoted to education of students and teachers in Hawai’i and the United Kingdom; and the SOLAR-C, a 20-inch telescope and spectrograph developed to observe the sun’s activities and corona.