Corning Mirror Blank 'Sagging' Complete

CORNING, N.Y., June 24 -- Corning Inc. announced it has completed the "sagging" process of the 4.2-meter ULE mirror blank that will serve as the primary mirror for Lowell Observatory’s Discovery Channel Telescope (DCT). ULE is a glass material that exhibits no dimensional changes over extreme temperature variations; it is generally considered to be one of best in the world for astronomical optics.

The sagging process consisted of creating a form made of refractories that meet the concave-convex shape requirements of mirror designers. The ULE mirror blank was positioned over the form and heated to approximately 2700° Fahrenheit to attain the material’s softening point. At this point, the blank began to sag around the refractories and conformed to the specifications of the mirror designers.

Work was performed at the Corning Semiconductor Optics facility, in Canton, N.Y. The company said work is now proceeding on the next phase of the program, the net grinding of the mirror blank.

The Discovery Channel Telescope (DCT) will be located at a new site being developed by Lowell Observatory on the Coconino National Forest in northern Arizona. The telescope will support research of Lowell Observatory astronomers and provide programming opportunities for Discovery Communications, the parent company of cable television's Discovery Channel.

When completed, it will be the fifth largest telescope in the continental United States. The telescope will have a wide variety of uses including: the search for potentially threatening earth-approaching asteroids, exploration of the outer solar system, including the newly discovered Kuiper Belt, and investigations of distant stars and galaxies.

The DCT has a unique optical configuration that allows it the ability to focus on a wide field or to be switched to a longer focal length. This attribute greatly exceeds the capabilities of today’s existing telescopes of the same class. The DCT, in a single wide field exposure mode, will allow astronomers to survey an area of the sky equal to the size of 16 full moons. In the longer focal length mode, the DCT will allow astronomers to zoom in on selected objects for detailed observation and subsequent analysis.

For more information, visit: www.corning.com