Equatorial ascendant

In astrology, the equatorial ascendant, or the East point, is the sign and degree rising over the Eastern Horizon at the Earth's equator at any given time.

In the celestial sphere it corresponds to the intersection of the ecliptic with a great circle containing the ecliptic poles and the East point of the horizon.

Equations derived from spherical trigonometry allow for the conversion from equatorial coordinates to ecliptic coordinates.

As points in the ecliptic have no latitude (β=0º) and the East point of the horizon has a right ascension 6h higher than that of the meridian (or 90º more in hour angle), the equation that determines East Point's longitude can be written as: where

is the local sidereal time and