Here’s How You Cast A $20 Million Mirror For The World’s Largest Telescope

world's largest telescope mirror


The world’s largest telescope is set to debut in 2023. In order to build that telescope a $20 million mirror is required.

If the price tag alone didn’t give it away you should know that this isn’t your average mirror. It has precise curves which require nanometer precision. The mirror(s) weigh 15-metric tons. And exhaustive tests are required before the mirror can be launched.

Here’s the description from below the YouTube video:

Building a mirror for any giant telescope is no simple feat. The sheer size of the glass, the nanometer precision of its curves, its carefully calculated optics, and the adaptive software required to run it make this a task of herculean proportions. But the recent castings of the 15-metric ton, off-axis mirrors for the Giant Magellan Telescope forced engineers to push the design and manufacturing process beyond all previous limits.

I’ve never seen a mirror getting cast let alone a mirror costing $20 million. So I can’t really say how this differs from your typical mirror casting process, but I’m still pretty blown away by everything that is going into this process.

The world’s largest telescope will debut in 5 short years and it will bring us into the future. This mirror is a massive component of making that happen. Given that the mirrors will need to be transported there I can’t help but imagine some truck accident on the drive there that involves micro-cracks in the mirror’s construction which sets everything back. This just seems like a logistical nightmare from all sides.