Clear view of globular cluster's crowded core - Sharpening a Heavenly Image - telescope picture of M-13 - Brief Article

Science News, June 14, 2003 by R. Cowen

Using innovative optics to take the twinkle out of starlight, a telescope in Hawaii has recorded the sharpest-ever infrared images of the globular cluster M-13, a crowded grouping of Milky Way stars. The resolution is comparable to discerning the separation between car headlights on the Golden Gate Bridge while standing 3,850 kilometers away in Hawaii. Researchers presented the images last week at a meeting of the Canadian Astronomical Society in Waterloo, Ontario.

Like other so-called adaptive-optics systems, the device installed on the Gemini North Telescope atop Hawaii's Mauna Kea reduces blurriness by using a flexible mirror whose computer-controlled shape changes 1,000 times per second to compensate for Earth's turbulent atmosphere. Compared with other systems, the Gemini device corrects for turbulence higher in the atmosphere, where most of it occurs, and thus sharpens images over a slightly wider region of sky, notes project scientist Glen Herriot of the National Research Council of Canada in Victoria, British Columbia.

Gemini imaged the center of M-13 at several infrared wavelengths, which will enable astronomers to determine the type, mass, and age of individual stars, says Tim Davidge of the National Research Council.