Giant Magellan Telescope

[Waspie_Dwarf]

Magellan super-scope gets green light for construction

Construction of the Giant Magellan Telescope has been given the go-ahead.

One of the largest optical observing systems ever conceived, the GMT will sit atop Cerro Las Campanas in Chile.

With its 24.5m-wide primary mirror system, astronomers should be able to see the first objects to emit light in the Universe, investigate dark energy and dark matter, and identify potentially habitable planets.

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[Merc14]

This telescope is going to be extraordinary and what a piece of engineering! Here is a 6+ minute movie made by the Magellan team

[+Noteverythingisaconspiracy]

Here is a little comparison chart of existing and planned telescopes:

I remember when the BTA-6 was considered to be the largest practical size a telescope could get.

Edited June 5, 2015 by Noteverythingisaconspiracy

[Merc14]

There must be some advantage to building an array with a few really large mirrors, like in the Magellan, rather than combining an array of a lot of little mirrors. Will the Magellan see as well as the proposed European Extremely Large Telescope? The E-ELT has 978 square meters of collecting area compared to 368 for the Magellan so no comparison there but is the picture quality better because of fewer but larger mirrors? Has to be enough advantage advantage to take the risk.

[Waspie_Dwarf]

There must be some advantage to building an array with a few really large mirrors, like in the Magellan, rather than combining an array of a lot of little mirrors. Will the Magellan see as well as the proposed European Extremely Large Telescope?

Yes, it's cheaper.

The E-ELT has 978 square meters of collecting area compared to 368 for the Magellan so no comparison there but is the picture quality better because of fewer but larger mirrors?

Define "picture quality".

The limiting magnitude (dimmest visible object which can be seen) is a result of the collecting area of the scope, so the E-ELT will be able to see object that the GMT won't.

The resolving ability (the finest detail that can be seen) is a result of the radius of mirror/lens used so again the E-ELT should be superior.

Has to be enough advantage advantage to take the risk.

You are putting the cart before the horse, the risk taking is being done by the E-ELT NOT the GMT.

The GMT will use just 7 mirrors of two designs... the six outer mirror will be identical to each other whilst the central mirror will be essentially a large but conventional mirror. With the E-ELT, if you consider the mirror arrangement as concentric rings of mirrors then each mirror within a ring will be ground to the same shape as another mirror within the same ring, however the shape needed for the next ring is different. Rather than just two mirror shapes there will be dozens.

E-ELT will be the superior instrument but has an estimated price of about $1.4 billion compared to the GMT which is around $700 million.

Edited June 5, 2015 by Waspie_Dwarf

[Merc14]

Thanks Waspie. Interesting video on creating one of these big mirrors and why they prefer to go with as few segments as possible. One problem you have with big mirrors is simply transporting them from point A to point B so maybe there will ultimately be a limit on how big any one segment can be simply because it gets exponentially harder to transport and service.

and

Interesting stuff and I can't wait to see and read about the results