Washington: A new type of camera snaps the sharpest images of the night sky than ever before, achieving image resolution that could see a baseball diamond on the Moon, astronomers say.
The camera system uses a telescope mirror that vibrates a thousand times each second to counteract atmospheric flickering, researchers said.
Astronomers at the University of Arizona (UA), the Arcetri Observatory near Florence, Italy and the Carnegie Observatory have been developing this technology for more than 20 years now and they have deployed the latest version of these cameras in the high desert of Chile at the Magellan 6.5-meter telescope.
“It was very exciting to see this new camera make the night sky look sharper than has ever before been possible,” said UA astronomy professor Laird Close, the project’s principal scientist.
“We can, 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. At that resolution, you could see a baseball diamond on the Moon,” said Close.
The two-fold 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.
“As we move towards shorter wavelengths, image sharpness improves,” said Jared Males, a NASA Sagan Fellow at the UA’s department of astronomy.
“Until now, large telescopes could make the theoretically sharpest photos only in infrared – or long wavelength – light, but our new camera can take photos that are twice as sharp in the visible light spectrum,” Males said.
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.
Until now, Hubble always produced the best visible light images, since even large ground-based telescope with complex adaptive optics imaging cameras could only make blurry images in visible light, researchers said.
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.
The study was published in the Astrophysical Journal.
