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 seventh — and 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.