Phobos: close-up, from Mars Express

This striking close-up image of Phobos was obtained by the Super Resolution Channel (or SRC, a part of the High Resolution Stereo Camera experiment) on board ESA’s Mars Express on 26 July 2008 (orbit 5861). The distance from the moon’s centre was 2295 Km, and the image resolution is 20 mt/pixel.
The Super Resolution Channel (SRC), is an additional camera sharing HRSC’s processing electronics. Unlike HRSC, SRC is a framing camera, taking a complete image during a single exposure like a conventional pocket camera. Its 975 mm Maksutov-Cassegrain telescope gives it a pixel-resolution about four times higher than that of HRSC.

Early in the mission, the thermal conditions of the instrument in space caused a distortion in its precision optics. This resulted in a performance lower than expected, with some blur and ghosting visible in the raw images.
However, a significant part of the degradation has now been compensated for by analysing the effect of the distortion on test images (with point-like stars as target) and applying a corrective processing.