STEREO Achieves Full Solar Coverage: All the Sun. All the Time

This movie illustrates the orbital motions of the two STEREO spacecraft relative to the Earth (and noting the positions of the planets Mercury & Venus for reference). The camera occupies a position fixed relative to the Earth and Sun, so the distant starfield appears to spin around the observer.

Because the frames are sampled at one per solar day, the Earth does not appear to rotate, but patient observation reveals that the tilt of the planet relative to the Sun, varies throughout the year, with the northern hemisphere tilted towards the Sun in northern hemisphere summer and away from the Sun in northern hemisphere winter.