[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:

[crz]

Man! How the hell do they polish that?

[Redcitizen]

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

[zeestephen]

Question to anyone...

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

[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/.

[lefty-lie-spy]

This sucker won’t even start to come online until 2023.

[4Liberty]

Bump!

[mabarker1]

Very Cool....
Thank You

[minnesota_bound]

960 inches or 24,384mm for the entire telescope.
24,384mm / 25mm = 975x magnification.
I guess we still won’t be seeing Martians.

Calculating Magnification
The magnification is the telescope focal length divided by the eyepiece focal length, in millimeters.

Magnification = Telescope focal length ÷ Eyepiece focal length

For example, if you use a telescope of 1000mm focal length with a 25mm eyepiece, the magnification would be 40x (1000mm ÷ 25 = 40). Doubling the power gives you one-fourth the image brightness and reduces the sharpness by one half.
https://www.telescope.com/Telescope-Power-Magnification/p/99813.uts

[PLMerite]

“The GMT will be largest telescope in existence, at least until the Thirty Meter Telescope and the European Extremely Large Telescope supersede it.”

...and the Trump Telescope comes online...