Diurnal parallax is a parallax that varies with rotation of the Earth or with difference of location on the Earth.
From the en.wikipedia.org
When the telescope became available, the diurnal parallax of Mars was again measured in an effort to determine the Sun-Earth distance.
From the en.wikipedia.org
Since this new star displayed no detectable diurnal parallax, Galileo concluded that it was a distant star, and therefore disproved the Aristotelian belief in the immutability of the heavens.