An extremely large telescope is an astronomical observatory featuring an optical telescope with an aperture for its primary mirror from 20 metres up to 100 metres across, when discussing reflecting te
The domes of the ELT, the TMT and the GMT compared to other well-known telescopes
Extremely Large Telescope
The Thirty Meter Telescope is a proposal for an extremely large telescope, intended to be built on Mauna Kea, on the island of Hawai'i.
Extremely large telescope
…GMT: Giant Magellan Telescope TMT: Thirty Meter Telescope Some of these projects have been cancelled, or merged into ongoing extremely large telescopes…
The Thirty Meter Telescope design, late 2007
Cultural practitioner Joshua Lanakila Mangauil, along with Kahoʻokahi Kanuha and Hawaiian sovereignty supporters block the access road to Mauna Kea in October 2014, demonstrating against the building of the Thirty Meter Telescope.
Inverted flag being flown next to Mauna Kea access road as a sign of protest, September 2023. Inverted flags can also be used as a distress signal