Astronomers have taken what appears to be the sharpest image of the moon ever recorded from Earth. The image, which shows a small area on the rim of a 56-kilometer-wide lunar crater called Taruntius, resolves features as small as 130 meters across.
Scientists accomplished the feat by employing a computerized system, called adaptive optics, that automatically compensates for the blurring of images by our planet’s turbulent atmosphere. Adaptive-optics systems normally work by keeping a bright guide star in sharp focus. If the computerized system can flex a telescope mirror rapidly enough and in just the right way to maintain the star’s image as a point rather than a blur, it will also keep in focus other objects in the same field of view.
But just before sunrise last April 30, scientists working with an adaptive-optics system mounted on one of the four telescopes collectively known as the Very Large Telescope in Paranal, Chile, decided to test the system in a different way. Instead of taking a pointlike star as their guide, they opted to use an extended object–a sunlit lunar mountain. Locking onto a mountain located between Mare Foecunditatis and Mare Tranquillitatis, the optics system produced a spectacularly detailed image. The European Southern Observatory released it Aug. 9.