Instrument shooting has autonomous pointing and observation satellite comprising such an instrument

System (220) of observation and image acquisition in space, for observation satellite, comprising at least one instrument taken (221) pointing to an observed target which receives a light signal from said target and outputs a frame of said target in the form of an analog signal, a converter (123) of said analog signal into a digital signal, an on-board computer (224) which performs compression of the images contained in said digital signal, means (125) for storing said compressed image, said system (220) being characterized in that it further comprises means for detecting parasitic movements of said system in space, including attitude drifts, means, set implemented by said on-board computer (224) for calculating a compensation of said parasitic movements for a pointing end of the instrument taken (221) toward the target and actuation means (225) converting said compensation in a direct mechanical action on at least one movable mirror (222) located in the path of the light signal inside of the instrument taken (221) and reflecting said signal to the focal plane (223) of said instrument (221).