The Giant Magellan Telescope will be one of the next class of giant telescopes that promises to revolutionize our view and understanding of the Universe. It is located at Las Campanas Observatory in Chile and will be operational in the next decade.

GMT has a unique design that offers several advantages. Its segmented 25-meter primary mirror is made from seven of the largest, stiffest mirrors ever made. Each segment is an 8.4 meter (28-foot) honeycomb mirror made at the Mirror Lab. GMT will have a resolving power 10 times greater than the Hubble Space Telescope. The GMT project is the work of a distinguished international consortium of leading universities and science institutions.

As of July 2019, the first two segments are finished and three more segments have been cast. These photos were taken before and after the casting of GMT Segment 5 in the winter of 2017-18. The video explains the casting process in more detail.


Honeycomb mold ready for glass, October 2017


Ohara E6 low-expansion glass loaded and ready to melt, November 2017



Furnace open after 3 months of annealing and cooling, February 2018

Another High Quality blank

Ray Bertram, Steward Observatory
Another high-quality GMT mirror blank