Animation: Phobos transit of Mars
The animated sequence shows the shadow of Phobos transiting Mars' disk on 24 February 2007; the sequence was captured around 22:08 CET, a few hours prior to Rosetta's successful Mars swingby on 25 February 2007.
The movie was produced by combining a series of separate images taken by by the Optical, Spectroscopic and Infrared Remote Imaging System (OSIRIS) on board Rosetta.
The background of Mars changes slightly from image to image since the individual images were acquired using different colour filters. Phobos appears dark because it reflects less sunlight than Mars.