Equipartite Times

Definition

Equipartite times are the times measured along the celestial equator — the right-sphere ascensions, isēmerinoi chronoi (Greek ἰσημερινοὶ χρόνοι, "equinoctial times"). Every sign takes the same count of these times to rise, to set, and to culminate, whatever quarter of the sky it is in. So they serve as a uniform measure for turning an arc of the zodiac into time. This sets them apart from the local rising-times, which vary with latitude.

In Tradition

In Hephaistio's transmission of Ptolemy's length-of-life direction-method, the equipartite times are the universal yardstick. They convert zodiacal distance into time and into years of life. Schmidt's annotator note fixes the definition plainly: they are the times along the equator. On the right sphere they meet the meridian and the horizon alike at an even rate. The signs traverse those circles in equal numbers of times from every quarter, which is exactly why the method adopts them rather than the latitude-dependent oblique times.

In Practice

Hold the distinction clearly. The rising-times you may already know are oblique, tied to a particular place on earth; the equipartite times are right-sphere, the same everywhere because they are reckoned on the equator. In the length-of-life direction you use them as the steady conversion rate. Once you know how far the destructive degree must travel to reach the place of releasing, the equipartite times turn that arc into a count of years. They are the equator's neutral clock, used where a local clock would distort the measure.

Historical Origin

The doctrine is transmitted in Hephaistio of Thebes, Apotelesmatics Book II (chapter on the length-of-life method, pp. 51-52, in Robert Schmidt's translation). There the equipartite times are defined as the times of the right sphere and adopted as the measure for the direction; Schmidt's annotator Note 99 fixes them as the times along the equator.

Etymology

Origin: Greek. Meaning: equinoctial times; the times along the equator.

Further Reading

• Hephaistio of Thebes, Apotelesmatics Book II
• Chris Brennan, Hellenistic Astrology