The antisolar point is the imaginary point on the celestial sphere exactly opposite the Sun. It is where anticrepuscular rays appear to converge, and on a moonless night away from city lights, it is often possible to see the gegenschein there. The apex of a rainbow will also form roughly 42 degrees above the location of the antisolar point. In astronomy, the sky position of the full moon and planets when they reach opposition are projected close to the antisolar point.