The Almanac represents Maskelyne’s enduring contribution to navigation—and the perfect task for him, too, as it embodied an abundance of excruciating detail: He included twelve full pages of data for each month, abbreviated and in fine print, with the moon’s position calculated every three hours vis-à-vis the sun or the ten guide stars. Everyone agreed, the Almanac and its companion volume, the Tables Requisite, provided the surest way for mariners to fix their positions at sea.
