The Istuban Calendar is the preferred method to measure dates in Southeast Yarth. It is made up of four seasons of a dozen seven-day weeks, each divided by a festival week. Years are counted from the founding of Kingtown.

There are a sixteen major constellations in the sky that make up the zodiac, as well as over a score of lesser constellations. Other celestial bodies include Yarth's two moons, and four planets that cross the sky each named for one of the elements.