of the horizon with the ecliptic can be calculated from:

where is the local sidereal time in degrees, is the inclination of Earth's equatorial plane to the ecliptic (axial tilt). For values referred to the standard equinox J2000.0 use = 23.4392911°; for J1950.0 use = 23.4457889°. is the observer's terrestrial latitude (southern latitudes are negative, northern positive). The ascendant is