Nation & World News

Tons Of Molten Glass Go Into Making Mirror For Giant Telescope

By Scott Neuman on August 24th, 2013

Technicians on Saturday are set to cast 20 tons of glass for the third of seven ultra-precise primary mirrors that will make up the 72-foot Giant Magellan Telescope, scheduled for completion in northern Chile’s arid Atacama Desert in 2020.

The parabolic mirror will be cast at the University of Arizona’s Steward Observatory Mirror Lab. The molten borosilicate, made by the Ohara Corporation, will be spun cast at 2140 degrees Fahrenheit.

Describing the production of the first such mirror in 2005, the Lab explained the process:

The glass was “… melted in a rotating furnace until it flowed into a honeycomb mold. Once the glass had cooled and the mold material was removed, scientists at the lab used a series of fine abrasives to polish the mirror, checking its figure regularly using a number of precision optical tests.”

How precise?

Once the mirror cools, and the polishing complete — a process that is expected to take a year — it will be accurate to within 1/20 the wavelength of light, or put another way, “one part in 10 billion in terms of precision manufacturing,” according to Patrick McCarthy, the project’s director.

When finished, the telescope — which includes another seven smaller mirrors to direct the collected light to a focal plane — will employ adaptive optics to compensate for atmospheric disturbances that might otherwise blur the image. The GMT is expected to offer 10 times the resolution as the Hubble Space Telescope.

“We have to make this optic precise enough so that when the light travels five, 10 billion light years and comes and hits our telescope that we don’t scramble and lose that information that’s traveled for so long,” McCarthy says in the video below describing the mirror-making process.

Scientists hope the new telescope will give them a better look at super-massive black holes that are believed to be at the heart of most large galaxies and to detect and characterize new planets outside our solar system.

“Astronomical discovery has always been paced by the power of available telescopes and imaging technology,” said Peter Strittmatter, head of the Steward Observatory’s astronomy department, in a press statement, according to SPACE.com. “The GMT allows another major step forward in both sensitivity and image sharpness.”

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

This entry was posted in News from NPR. Bookmark the permalink.

Comments are closed.

 

More Stories in News from NPR

Pope Francis as he celebrated communion last July in Brazil.

Pope OKs Communion For The Divorced? Not So Fast, Vatican Says

Word about what the pope reportedly said when he called a woman in Argentina set off speculation that he wants to reverse church teachings. His spokesman says that’s reading too much into the story.


U.S. journalist Simon Ostrovsky in Moscow in 2004. He was reportedly released on Thursday after being held briefly by pro-Russian separatists in eastern Ukraine.

American Journalist Freed By Kidnappers In Eastern Ukraine

Simon Ostrovsky, a reporter for Vice News, was seized at gunpoint by masked men in the city of Slovyansk earlier this week. Vice says he is now safe and in good health.


The steamship "City of Chester" in a photograph from the San Francisco Maritime National Historic Park.

Long-Lost Wreck Off San Francisco Recalls Anti-Chinese History

The City of Chester, which sank in 1888 after colliding with the liner Oceanic, has been found. At the time, false reports that the other ship’s Chinese crew failed to assist stoked racial hatred.


Israel Halts Peace Talks After Palestinian Unity Move

The Israeli Cabinet on Thursday endorsed Prime Minister Benjamin Netanyahu’s decision to suspend talks because the Palestine Liberation Organization and Hamas are moving to form a unity government.


Lawyers Use High Court Petition To Highlight Prosecutorial Misconduct

A computer support technician convicted of possessing ricin to use as a weapon wants the Supreme Court to hear his appeal. He says prosecutors denied him due process by failing to disclose evidence.


Thank you for your support

WUFT depends on the support of our community — people like you — to help us continue to provide quality programming to North Central Florida.
Become a Sustainer
I want to support FM 89.1/NPR
I want to support Florida's 5/PBS
Donate a Vehicle
Underwriting Payments