The time from the rising of a planet to its setting, divided by 12, gives its horary time, which is 1/12th of the time between the rising and setting of a planet - or the reverse, according as the planet is placed in the diurnal or nocturnal circle. The factors employed in this calculation are the declination of the planet and the latitude of the place. (v. Ascensional Difference.)
ASTROLABE ENCYCLOPEDIA
