The Giant Magellan Telescope

The James Webb Telescope (JWST) made history with the deepest, highest-resolution image of the cosmos ever seen. Can you imagine something four times more powerful and ground-based here on Earth?

The Giant Magellan Telescope (GMT) is currently being installed at Las Campanas Observatory in the Atacama Desert, one of the darkest locations on Earth.

The telescope is located at Las Campanas Observatory,71 mi north-northeast of La Serena, Chile, and 112 mi south of Copiapó, Chile, at an elevation of 28,255 ft.

Located at one of the darkest places on Earth, the Atacama Desert is the driest nonpolar desert in the world. This makes the site ideal because of its superior astronomical seeing and clear weather throughout most of the year.

The telescope has seven primary mirrors with a combined light-gathering power of 368 square meters, nearly 4000 square feet.

A 22-story high, state-of-the-art enclosure protects the GMT. The alt-azimuth mount provides an incredibly stable platform. The walls drop out of the way, offering an unobstructed view. The 22-meter diameter concrete pier isolates the equipment from the tiniest vibrations.

The Mirrors Change Shape to Eliminate Distortions

Adaptive optics adjust for atmospheric distortions at 2,000 times per second.

Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of incoming wavefront distortions by deforming a mirror in order to compensate for the distortion.

When light from a star or another astronomical object enters the Earth's atmosphere, atmospheric turbulence (introduced, for example, by different temperature layers and different wind speeds interacting) can distort and move the image in various ways. Visual images produced by any telescope larger than approximately 20 centimeters are blurred by these distortions.

An adaptive optics system tries to correct these distortions, using a wavefront sensor which takes some of the astronomical light, a deformable mirror that lies in the optical path, and a computer that receives input from the detector. ~Wikipedia

The mirror lab at University of Arizona

The mirror lab at University of Arizona makes massive mirrors for our ground-based telescopes, including the Giant Magellan Telescope segments.

Starting with ultra-pure and clear cutlet glass, the lab melts, spins, and then polishes the glass blank, becoming one of the mirror segments for the GMT and other telescope projects.

What will the astrophotography reveal when this telescope is put into operation?

The project just announced this August that it is to receive a $205 Million investment that accelerates the construction of the Giant Magellan Telescope

In 2009, I had a look inside The Mirror Lab at University of Arizona. Here the mirrors are made by melting purified glass and then slowly cooling it and then polishing the surface to exact specifications.

The telescope will use seven of the world's largest mirrors as primary mirror segments, each 8.417 m (27.61 ft) in diameter. These segments will then be arranged with one mirror in the center and the other six arranged symmetrically around it. The challenge is that the outer six mirror segments will be off-axis, and although identical to each other, will not be individually radially symmetrical, necessitating a modification of the usual polishing and testing procedures.[18]

The mirrors are being constructed by the University of Arizona's Steward Observatory Richard F. Caris Mirror Lab.[19] The casting of the first mirror, in a rotating furnace, was completed on November 3, 2005, but the grinding and polishing were still going on 61⁄2 years later when the second mirror was cast, on 14 January 2012.[20][21] A third segment was cast in August 2013,[11][22] the fourth in September 2015,[23] the fifth in 2017,[24] and the sixth in 2021.[10] The casting of each mirror uses 20 tons of E6 borosilicate glass from the Ohara Corporation of Japan and takes about 12–13 weeks.[25] After being cast, they need to cool for about six months.[11]

Polishing of the first mirror was completed in November 2012.[26] As this was an off-axis segment, a wide array of new optical tests and laboratory infrastructure had to be developed to polish the mirror. ~Wikipedia