LBT Publishes "First Light" Image

FarmKing writes "The Large Binocular Telescope has achieved "first light" and published it's first image of NGC891. The image was taken with one of it's two 8.4 Meter (~655 ft^2) mirrors. When fully operational, LBT will be one of the largest optical telescopes in the world."

Comments

Re:hubble?

[beeplet]

From this page it looks like the two telescopes in combination have a resolution 10x that of Hubble. Hubble's primary mirror is 2.4 m in diameter compared to the LBT's 8.4 m (but atmospheric distortion lowers the resolution of ground-based telescopes). The main advantage to the dual-telescope set-up is not the increased resolution, but the ability to do optical interferometry: cancel out the signal that you don't want, or select for the signal that you do.

The Keck Telescope in Hawaii is also designed to do optical interferometry, though I'm not sure what kind of results they have gotten so far.

Defn:

[lurch84]

For those not in the know, "First Light" is when a telescope is first used to capture an image after construction.

Re:hubble?

[deglr6328]

The Kecks, though they are capable of nulling interferometry, are not capable of imaging interferometry. Or at least they will not be capable of it until they complete the construction of the 4(?) small "outrigger" telescopes around the two Kecks currently on the top of the mountain. The completion of these small outriggers has been delayed for several years however because of the (idiotic) cries of "oh noes it will disturb the sacred mountain spirits so you can't build anything there ever anymore!!" from native Hawaiian tribe organizations. The binocular telescope in Arizona, when finished, will be ready right away to perform full imaging aperture synthesis with a ~22 meter baseline and simultaneous adaptive optics correction (with future capability for advanced multi-conjugate adaptive optics correction). This should (theoretically) allow near .005 arcsecond resolution in the visible spectrum to be achieved. Very exciting.

Re:Only one mirror?

[dierdorf]

> Is what's clear to me and the pictures seem to indicate that only one mirror is currently installed?

Yes. The second mirror is still being polished and will be installed sometime next year.

By the way, EACH mirror of the LBT is the largest single mirror in the world at 8.4 meter diameter. The Subaru telescope on Moana Kea is 8.2. There are larger telescope mirrors (Keck I and II, HET, and SALT), but they are segmented. Now that Arizona knows how to cast 8.4m mirrors, they are making the first of SEVEN of them for the next-generation Giant Magellen Telescope.