How does FUSE point at stars and galaxies in space?
Pointing the telescope in the right direction and locking onto the astronomical (or celestial) objects of interest is something FUSE has been designed to do for itself! It takes coordination between the computer on the “spacecraft” and the computer in the telescope itself, as well as information provided by the Fine Error Sensor (FES) guide camera. The FES camera takes pictures, and by identifying the stars seen, the on-board computer can find EXACTLY where the instrument is pointed! Once its position is determined, FUSE can aim in a new direction and find another set of expected stars, including the object scientists want it to observe in ultraviolet light. Knowing where FUSE should point is only part of the challenge. To actually turn the telescope requires the ability to make precise rotations about three axes in space. But the FUSE spacecraft does not include any jets or rockets to turn its telescopes around this sky. Instead it uses basic physics: the law of conservation of angula
