Roger Angel, University of Arizona Regents' professor of astronomy and optical sciences, left, talks with a visitor about the 8.4-meter honeycomb mirror.

Photos by James S. Wood / arizona daily star

More Photos (1):

Other articles by Tom Beal:

Astronomer to explain why he let Pluto down Enthusiasm for Obama high for Tucson's blacks UA genomics lab tackles Holocaust puzzle Architect chosen for Historical Society's Rio Nuevo museum '06 cascade of boulders was rare, but a red flag, too Asteroid searcher hopes his discoveries won't produce direct impact Towering turbines coming to AZ Danny's gone, but he helped his O'odham culture live on Student group off and running with UA plan for sustainabilityUniversity of Arizona students have major plans to make campus 'green'

Education
Assessment Technology, Inc
Social Studies Content Writer Construction
Komatsu Equipment Co
Mechanic General
CORT
Warehouse Supervisor Health Care
Rio Salado College
PA's/Online Instructors General
CORT
WAREHOUSE/DRIVER

The UA Steward Mirror Lab has lifted the lid on its latest 8.4-meter mirror blank and pronounced it near-perfect — ready for a custom grinding and polishing job that will make it the most unusual telescope mirror ever built.

This single glass blank will actually become two mirrors, part of the novel three-mirror system of the Large Synoptic Survey Telescope. It will give astronomers the widest, deepest, most data-filled look at the night sky ever attempted.

When it is installed on a Chilean mountaintop in 2015, it will be capable of mapping the entire night sky in digital images every three days, gathering 15,000 gigabytes of information each night and making it available to astronomers worldwide for research.

University of Arizona astronomer Roger Angel, who first proposed the project in a paper 10 years ago, said the telescope's usefulness is magnified by its wide field of view, the depth of its light-gathering reach and the widespread dissemination of the images it will gather.

Astronomers looking for changes from image to image over time will be able to more easily spot potentially threatening near-Earth objects, exploding supernovae, comets and other phenomena.

It will also aid them in locating dark matter and energy by noting their effect on light from distant galaxies.

"It will provide vast amounts of new things," Angel said. Researchers, he said, "will be in the nice position of being able to pick and choose."

The outer section of the concave blank will keep its current curvature, created by slowly spinning molten glass in a honeycomb structure Angel developed that has made Steward the world's premier creator of large telescope mirrors.

The inside 16 feet of the mirror blank will be ground to a steeper concavity.

When installed, the outer, or primary, mirror will receive light from the night sky and bounce it to a mirror above it, which in turn will bounce it to the interior mirror of the blank recently cast.

That mirror will bounce the light to a digital camera with an aperture nearly 2 feet square, providing it with a field of view larger than 30 moons.

There were no hitches in casting the mirror, said Jeffrey S. Kingsley, associate director of Steward Observatory.

Storms knocked out power to the mirror lab, which is beneath the UA football stadium, once while it was melting glass, but generators came on well before there was any measurable change in heat.

Grinding and polishing, during which about 16,000 pounds of glass will be removed from the mirror's surface, could take up to two years, said Kingsley.

The LSST Corp., which will build and operate the telescope, is a consortium of 25 universities and institutions, headquartered in Tucson.

Founding partners are the UA, the University of Washington, the National Optical Astronomy Observatory and Research Corp. It plans to begin operating the scope in 2015.

Money for the mirrors themselves came from private donations — $10 million from Microsoft owner Bill Gates and $20 million from the Charles Simonyi Fund for Arts and Sciences, according to a UA news release.