Method for measuring the stability of a line of sight and corresponding star sensor

The method involves capturing a first set of star images (14) using a capturing head (6) of a star sensor (4) at frequency in a successive manner, where the sensor comprises another capturing head (5) for capturing a second set of star images (10) at another frequency that is lower than the former frequency. Information relative to angular displacement of a line of sight is deducted from relative displacement of a star in the two sets of the images, where the former frequency is higher than 30 Hertz. Independent claims are also included for the following: (1) a method for measuring mechanical vibrations of a device (2) a method for processing images (3) a method for controlling an attitude of a satellite (4) a satellite.