Mar 5, 2021 - Science

A giant telescope is coming together

A huge plate of dimly lit glass being placed into a furnace by a man in a white clean room suit

Preparing the glass for the mirror. Photo: Giant MagellanTelescope–GMTO Corporation

Scientists started on Friday casting one of the largest telescope mirrors ever made on Earth for the Giant Magellan Telescope being built in Chile.

Why it matters: The huge telescope is designed to one day peer into the atmospheres of potentially habitable planets around far-off stars, learn more about early galaxies and study other objects of interest.

What's happening: The mirror is being crafted in Arizona using the only spinning furnace in the world designed for this kind of casting.

  • On Saturday, the furnace will hit "high fire," spinning at five revolutions per minute and heating the glass to 2,129 degrees Fahrenheit for about five hours to liquify it.
  • After that peak in heating, the glass will gradually cool for about a month while the furnace spins more slowly, eventually reaching room temperature about 2.5 months after high fire.
  • "Once cooled, the mirror will be polished for two years before reaching an optical surface precision of less than one thousandth of the width of a human hair or five times smaller than a single coronavirus particle," the GMT organization wrote in a press release.

What's next: The GMT's first two mirrors are ready and in storage, with three others still in process. The seventhand last mirror is scheduled to be cast in 2023.

  • The team behind the telescope is also planning on crafting an eighth mirror as a spare.
  • The telescope is expected to see first light in 2029.
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