Antisolar point

On a sunny day, the antisolar point can be easily found; it is located within the shadow of the observer's head.

Like the zenith and nadir, the antisolar point is not fixed in three-dimensional space, but is defined relative to the observer.

The antisolar point forms the geometric center of several optical phenomena, including subhorizon haloes, rainbows,[2] glories,[3] the Brocken spectre, and heiligenschein.

[5] Also around the antisolar point, the gegenschein is often visible in a moonless night sky away from city lights, arising from the backscatter of sunlight by interplanetary dust.

During a total lunar eclipse, the full Moon enters the umbra of Earth's shadow, which the planet casts onto its atmosphere, into space, and toward the antisolar point.

A rainbow has 42° centered around the antisolar point, which always coincides with the shadow of the observer's eye/camera, seen here at the bottom of the frame.
Drawing by René Descartes explaining the formation of a rainbow . The antisolar point is the center of the rainbow M . It lies at the end of the straight line running from the sun through the observer's eye E .
Centered on the antisolar point, this photo features various antisolar/subhorizon haloes , as viewed from a plane.