a pitch constellation is a graphical representation of pitches used to describe musical scales, modes, chords or other groupings of pitches within an octave range. it consists of a circle with markings along the circumference or lines from the center which indicate pitches. most pitch constellations use of a subset of pitches chosen from the twelve pitch chromatic scale. in this case the points on the circle are spaced like the twelve hour markings on an analog clock where each tick mark represents a semitone.