An Angle of the Horoscope

The Descendant is the point of the ecliptic setting on the western horizon at the moment and place of a chart, formed where the ecliptic crosses the local horizon on its westward, descending side, directly opposite the Ascendant on that same horizon line. It is the cusp of the seventh house and one of the four angles of the chart.

Because it sits exactly 180 degrees from the Ascendant, the Descendant was never treated in Hellenistic sources as a separate technical starting point the way the horoskopos was; rather it followed automatically once the Ascendant, and so the whole ecliptic-horizon relationship, was fixed. Vettius Valens and Ptolemy both discuss the horoscopic angles as a linked set of four kentra, or cardines in Latin, rather than describing the setting point on its own, and the seventh place that the Descendant heads already carried associations with marriage and open conflict in the surviving Hellenistic manuals, showing the angle was in active technical use even where the Greek and Latin sources rarely name it individually. The point marks where the sky's daily rotation carries the ecliptic below the western edge of the visible sky, the mirror event of the Ascendant's rising, and together the Ascendant-Descendant line forms one of the two great axes, horizon and meridian, that structure every quadrant based chart.