The sign for "moon" uses a "modified C" hand consisting of the index finger and the thumb in a "C" shape. Think of looking at a crescent way up in the sky.
MOON:
There is another version of "moon." This version means the same as the above version. This one taps the modified C handshape on the face twice. The index finger is above the eye and thumb is below the eye.
MOON (version)
See: SUN
Notes: