Wednesday, October 5, 2011

ALMA, the World's Largest Radio Telescope, Grabs Its First Images

ALMA's First Image This is ALMA's first image, 
showing the Antennae Galaxies in two different 
wavelength ranges. The image was captured during 
the observatory's early testing phase, using only 12 
antennas working together — the array will 
eventually have 66. European Southern Observatory

The world’s largest astronomical facility has opened its eyes, turning nearly two dozen antennae toward the heavens to study the building blocks of the cosmos. The Atacama Large Millimeter/submillimeter Array consists of 20 radio antennae for now, but will contain 66 by 2013, giving it a higher resolution than the Hubble Space Telescope.

Appropriately enough, the first images captured the Antennae Galaxies, a pair of colliding galaxies replete with stars and stellar nurseries. ALMA’s 39- and 23-foot dish antennae can resolve areas of dense, cold gas that other telescopes could not detect.

ALMAsits in the high Chilean desert, about 16,000 feet above sea level and above much of the interfering atmosphere. These pictures were made with 12 telescopes situated relatively close together; science observations during the next few months will be even clearer.

Closer-situated antennae yield a wide field of view, so astronomers can search for items they want to study in more detail. Moving the antennae farther apart provides a narrower focus, like using a finer lens on a regular telescope. Instead of tunable knobs, ALMA has 192 separate antennae pads for the huge dishes to be moved around.      More