That Giant Magellan Telescope (GMT) just got a good chunk of change to help develop and test the advanced technologies that will give the future observatory such a sharp vision.
The US National Science Foundation (NSF) has awarded a $ 17.5 million grant to GMTO Corporation, which is developing GMT and will drive the large scale when it comes up and running in Chilean Andes in the late 2020s.
The money, first donated to the GMT project by the NSF, “means the observatory will be important to the entire American astronomical community,” GMTO President Robert Shelton told Space.com.
“This award really allows us to accelerate our progress with critical components,”
Related: Giant Magellan Telescope presented in Chile (photos)
GMT integrates seven 27.6-foot (8.4-meter) primary mirrors into a single 24.5-meter (three-foot) light-collecting surface – three times wider than any optical telescope operating today. The wide range of applications will also include seven “adaptive secondary mirrors” (ASMs), each of which will be 3.3 feet (1 m) wide and only 2 millimeters thick with hundreds of actuators attached to the back.
“With them [actuators], we are able to bend this thin glass surface approx. 1000 times every second, “said GMTO project manager James Fanson to Space.com.” This is what we use to compensate for the distortion introduced by Earth’s atmosphere. Millisecond by millisecond, we measure the distortion and correct it so that we can essentially remove the atmosphere above the telescope and get very sharp images. “
These extreme optics will provide GMT 10 times the resolution of NASA’s famous Hubble Space Telescope, GMT team members have said. Astronomers will use GMT for a range of high-impact projects, ranging from hunting for signs of life in the atmospheres of nearby exoplanets to explore the nature of dark matter and dark energy, which dominates the universe but which largely remains mysterious.
Making all this happen, however, is no walk in the park. For example, no other telescopic mirror in a piece is larger than a GMT primary segment. And the surface of all seven GMT primary pieces must be shaped almost to perfection: the margin of error is only 25 nanometers (1 millionths of an inch), about the width of a single glass molecule.
The seven segments also need to be “phased” so that they are precisely aligned and act as a single piece of hardware. The newly awarded NSF money will help the GMT team demonstrate and practice just that at two custom-built phase test beds, one at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts and the other at the University of Arizona in Tucson. The grant also allows the team to partially build and test an ASM.
The grant-funded work will take place over three years and keep GMT on track for “first light” in 2029, team members said. And the benefits will extend beyond GMT, Fanson said, emphasizing that the technologies demonstrated will continue to be used by other telescopes in the future as well.
GMT development is generally going well, Shelton said, adding that the team has not yet seen any major impacts due to coronavirus pandemic.
Primary mirror segments 1 and 2 are finished, and segment 3 is being polished at the University of Arizona’s Richard F. Caris Mirror Lab now. Segments 4 and 5 are waiting to be polished, and segments 6 will be cast in the coming months, Shelton said. (Mirror Lab does all this work, from casting to final polishing.)
In October 2019, GMTO announced that it had done so signed a $ 135 million contract with MT Mechatronics and Ingersoll Machine Tools to build and install the telescope holder, the 1800 ton precision steel construction that will be the GMT bones.
The bracket is undergoing its preliminary design review now, Shelton said.
“It’s the one we really need to focus on now and make sure the design meets our needs, because literally everything interacts with the holder – the instruments, the mirrors, everything,” he said. “So that’s really the key right now.”
Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.