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.