They Just Began Casting the Giant Magellan Telescope’s 5th Mirror. What a Monster Job.

Universe Today ^ | 11/7/17 | Evan Gough

[LibWhacker]

For decades the largest optical telescope in the world was the Hale telescope on Mt. Palomar, which has a 200-inch primary mirror. Each of the seven segments on Magellan is 330 inches across, 65% larger than Hale's primary! They always told us you couldn't build an earth-bound mirror much larger than Palomar's because it would sag and crack under its own weight. But each of Magellan's seven segments is pushing that limit to the max! Amazing. Can't wait to see the images it's going to produce.

[Oldexpat]

If you visit Tucson the lab is under the stadium. Make reservations for a tour.

[bluejean]

Very cool!

[Telepathic Intruder]

All these bells and whistles just mean it's more expensive and harder to point. Galileo would say "ooo, isn't that fancy?"

[Bob434]

how many years bad luck would it be if they broke that mirror?

[radu]

Can't wait to see the images it's going to produce.

I hope I live long enough to see the images! They should be spectacular!

[montag813]

The Thirty Meter telescope planned for Mauna Kea in Hawaii is also an interesting design...larger, but relatively tiny mirror hexagon segments:

[LibWhacker]

Lol, I don’t know... It’s gotta be like eight thousand years!

[LibWhacker]

I hear ya. I’ll be pushing 80 in 2025. Odds aren’t good, but my fingers are crossed!

[LibWhacker]

Poor old Galileo. Fighting a lost cause. His dinky little telescope with poor optics didn’t help either.

[radu]

I’ll be in my mid 70s then so who knows?
We both need to keep ALL of our appendages crossed! LOL

[Vince Ferrer]

Poor old Galileo. Fighting a lost cause.

The science was settled.

[crz]

Man! How the hell do they polish that?

[Redcitizen]

That’s gonna take a lot of windex to keep clean.

[az_gila]

If you are visiting Tucson, a tour of the mirror lab is well worth a trip -

http://mirrorlab.tix.com/Schedule.aspx?OrgNum=4634&Disp=Cal&framed=true

[minnesota_bound]

#13 Since it is in Chile I am guessing with chili powder....

[zeestephen]

Question to anyone...

Is it possible to build a telescope that uses just light sensitive charge coupled devices instead of mirrors?

[zeestephen]

Re: How many years bad luck would it be if they broke that mirror?

Since its a telescope, bad luck would be measured in light years.

[lefty-lie-spy]

This GMT is pretty amazing. I often listen to the Universe Today podcast, though it can be a little dry and boring with that Dr. Pamella Gay droning on in that horrible deadpan voice, so I don’t listen as regular as I used to.

I found the “low expansion glass from Japan” company :

https://en.wikipedia.org/wiki/Ohara_Corporation

They have quite a technical website if you want to dig deeper.

[lefty-lie-spy]

And here’s more, straight from the source, https://www.gmto.org/2017/11/giant-magellan-telescope-organization-casts-fifth-mirror/.