Big boys' toys

They've started pouring the glass for the first of the seven 8.4m
mirrors which will make up the Giant Magellan Telescope. The scope
won't be finished till 2016, but I just love reading about big stuff,
especially big scientific instruments.

http://www.gmto.org/newsitems


Tim
--
Today's message was brought to you by Mary, Jane and a big number two.

Very exciting project. I wonder if there are any projections about the
GMT's limiting magnitude (faintest source) detection capabilities? I'd
imagine fainter than magnitude 30... which would be good for
Earth-sized exoplanet searching.

2016 is still a long way off though. :-(

AAI

wrote:

Very exciting project. I wonder if there are any projections about the
GMT's limiting magnitude (faintest source) detection capabilities? I'd
imagine fainter than magnitude 30...

Light pollution notwithstanding, molecules in the Earth's atmosphere
produce a natural skyglow. This means the record-holder for the
deepest optical image will remain HST.

which would be good for Earth-sized exoplanet searching.

Yes, if the GMT was in orbit.

2016 is still a long way off though. :-(

You won't have to wait until then. In the intervening 11 years,
Kepler will have bagged hundreds of transiting Earths (if they
indeed exist), SIM will study a select few and TPF/Darwin will
have directly imaged some of them.

"Tim Auton" wrote

They've started pouring the glass for the first of the seven 8.4m
mirrors which will make up the Giant Magellan Telescope. The scope
won't be finished till 2016, but I just love reading about big stuff,
especially big scientific instruments.

http://www.gmto.org/newsitems

Specifically it's a glass melting, not a pouring. The glass melts while the
furnace spins, and over time the spinning slows as the temperature is
reduced. So far, it appears this has been a successful casting.

Howard Lester

But will it have goto?

Tim Auton wrote:
They've started pouring the glass for the first of the seven 8.4m
mirrors which will make up the Giant Magellan Telescope. The scope
won't be finished till 2016, but I just love reading about big stuff,
especially big scientific instruments.

http://www.gmto.org/newsitems


Tim

On 2005-07-26, starburst wrote:

Tim Auton wrote:
They've started pouring the glass for the first of the seven 8.4m
mirrors which will make up the Giant Magellan Telescope. The scope
won't be finished till 2016, but I just love reading about big stuff,
especially big scientific instruments.

http://www.gmto.org/newsitems

But will it have goto?

When they are that big they all have goto.

--
The night is just the shadow of the Earth.

Ed wrote:

wrote:

Very exciting project. I wonder if there are any projections about the
GMT's limiting magnitude (faintest source) detection capabilities? I'd
imagine fainter than magnitude 30...

Light pollution notwithstanding, molecules in the Earth's atmosphere
produce a natural skyglow. This means the record-holder for the
deepest optical image will remain HST.

Interesting tidbit: the visible-light background from low Earth
orbit isn't all _that_ dark, due to starlight scattered by dust (both
zodiacal light and interstellar scattering). In the V band, HST's
nighttime background (free of scattered Earthlight) is about half
as bright as at the best ground-based sites. The comparison does
become more favorable at other wavelengths - the blue and eventually
UV orbital sky is extremely dark, and as one looks farther into the
near-IR the gain becomes factors of thousands, as the airglow
becomes brighter and brighter (and eventually not just airglow
but the thermal radiation of the atmosphere dominates).

For a particular wavelength, image quality, and aperture, one has to
run the numbers to compare straight limiting magnitude (although
the resolution advantage for faint objects will stay with HST for
some time yet). [Yes, AO gives image cores tighter than HST from
Keck or the VLT, especially in near-IR bands, but the wings on
the image can still be very messy if you care about details of
the structure of high-redshift galaxies.]

Bill Keel

Ed wrote:

2016 is still a long way off though. :-(

You won't have to wait until then. In the intervening 11 years,
Kepler will have bagged hundreds of transiting Earths (if they
indeed exist), SIM will study a select few and TPF/Darwin will
have directly imaged some of them.

Of course! I'd almost forgotten about all of those...

AAI