October 2, 2008—Jupiter looks sharp in the crispest whole-planet picture of the planet ever shot from Earth.
Captured using a new computer-assisted process and a 27-foot (8.2-meter) telescope in Chile, the result is sharp enough to show features as small as 180 miles (300 kilometers) across.
The extraordinary focus was achieved via a new form of adaptive optics, said project leader Franck Marchis, an astronomer at the University of California, Berkeley, and the SETI Institute.
Adaptive optics, Marchis said, adjusts for distortions caused by the Earth's atmosphere, "providing images as if the telescope was in space."
Traditionally, the method analyzesthe atmospheric turbulence of the light coming from a nearby star and correcting its effect in real time using a deformable mirror.
But that only allows correction for distortions along one line of sight.
The amount of distortion in slightly different directions varies, restricting the sharpest field of view to the center of the image.
The new technique, called MAD (for Multi-Conjugate Adaptive Optics Demonstrator), uses two or more guide stars, allowing it to remove blur from a field of view 30 times larger.
—Richard A. Lovett