Richard F. Caris Mirror Lab
The GMT’s mirrors are being produced by the Richard F. Caris Mirror Lab of the Steward Observatory of the University of Arizona. The GMT’s 24.5 meter primary mirror will be comprised of seven separate 8.4 meter diameter segments. Each of the primary mirror segments weighs approximately 17 tons and takes a year to cast and cool. After casting, the fabrication of each segment requires more than three years of surface generation and meticulous polishing. Learn more about the mirror production process in our FAQs.
GMT Segment 4
As of June 2017, the next stage of Segment 4 is to polish the rear surface.
GMT Segment 3
As of June 2017, Segment 3 has had its rear surface polished and load spreaders have been installed on the rear surface. The next stage will be processing the front of the mirror.
GMT Segment 2
As of June 2017, Segment 2 is undergoing front surface polishing.
GMT Segment 1
Segment 1 was completed in 2012.