Washington: Astronomers have developed a new type of camera which is helping them click sharper images of the night sky than ever before.
Astronomers at the University of Arizona, the Arcetri Observatory near Florence, Italy, and the Carnegie Observatory has been developing this technology for more than 20 years at observatories in Arizona, most recently at the Large Binocular Telescope, or LBT, and has now deployed the latest version of these cameras in the high desert of Chile at the Magellan 6.5-meter telescope.
Project`s principal scientist Laird Close said that it was very exciting to see this new camera make the night sky look sharper than has ever before been possible and for the first time, make long-exposure images that resolve objects just 0.02 arcseconds across-the equivalent of a dime viewed from more than a hundred miles away.
The twofold improvement over past efforts rests on the fact that for the first time, a telescope with a large diameter primary mirror is being used for digital photography at its theoretical resolution limit in visible wavelengths - light that the human eye can see.
These images are also at least twice as sharp as what the Hubble Space Telescope can make, because with its 21-foot diameter mirror, the Magellan telescope is much larger than Hubble with its 8-foot mirror.
To overcome atmospheric turbulence, which plagues Earth-based telescopes by causing the image to blur, Close`s team developed a very powerful adaptive optics system that floats a thin (1/16th of an inch) curved glass mirror (2.8 feet across) on a magnetic field 30 feet above the telescope`s primary mirror.
This so-called Adaptive Secondary Mirror (ASM) can change its shape at 585 points on its surface 1,000 times each second, counteracting the blurring effects of the atmosphere.