The largest optical telescope that will ever be built?

[Deane Clark]

Tom Scott has done a lot of interesting YouTube videos on a variety of topics, but he’s outdone himself this time. He visited the ELT (Extremely Large Telescope) under construction in Chile, and did a very comprehensive and fascinating 1/2 hour video on it. The scale of this thing is awe inspiring. Be sure to pause the video at the spot where you see a tower crane in the shot and you realize it is INSIDE the dome! The part about the ELT starts around the middle of the video, but the first half covers some basics about big telescopes and a tour of the VLT, including a visit to the basement where the beams are combined to do interferometry. So, don’t skip ahead

https://youtu.be/QqRREz0iBes?feature=shared

[kibatme]

Just finished watching the video. Your phrase "...covers some basics about big telescopes.." makes me smile. There are absolutely no
'basics' involved here. Simply stunning when you consider it's 430+ tons of metal and glass requiring nanometers worth of precision both mechanically and optically. Definitely worth your time, if you haven't yet viewed it!

[Dick Jacobson]

This is a really fascinating video for anyone who likes giant telescopes. His argument that the ELT is the largest optical telescope that will ever be built reminds me that the same was said about the 200-inch Palomar after it was built. He argues that advances in computers will soon make it possible to do optical interferometry by computer, the same as is now done with radio telescopes. This will make large single apertures irrelevant. The proposed 100-meter Overwhelmingly Large Telescope (OWL) might remain a pipe dream. Too bad!