While asteroids residing in the inner solar system will pass quickly through such small fields, trans-Neptunian objects (TNOs) orbit the Sun much more slowly. For example, Pluto, at an approximate distance of 40 A.U. from the Sun, along with the object Eris, presently the largest of the TNOs, has an apparent motion of about 27 arc seconds per day – although for a half year, the Earth’s orbital motion slows and retrogrades Pluto’s apparent motion. The 27 arc seconds is approximately 1/60th the width of a full Moon. So, from one night to the next, TNOs can travel as much...