NEOs are extremely close to Earth compared to the stars we see in the night sky. For this reason, an NEO’s movement can be detected against the backdrop of the stars. Taking images of the same region of sky at several minute intervals produces multiple ‘frames’, which can be run like a movie. Anything that is closer than the stars will appear to move across the screen. The animation below shows asteroid 2008 TC3 crossing from left to right as it moves against the background stars.