The Part of Fortune Among the Planetary Points

The Part of Fortune, kleros tyches in Greek and pars fortunae in Latin, is the most important of the Hellenistic lots: a point calculated from the positions of three others, most commonly the Ascendant plus the Moon minus the Sun in a day chart, with the Sun and Moon reversed at night. It appears in this list among the planets because most modern software plots it as a chart point alongside them, but it is a derived position and not a body. Ptolemy is the only one of the major Hellenistic authors to discuss the lots at any length, and he uses this one alone, taking it for the body, health and material circumstances of the life; other authors, Vettius Valens and Paulus Alexandrinus among them, use a much larger set. The atlas treats the lots as a group in their own section, where the formula and the wider family of parts are set out.

Robert Hand and Robert Schmidt's Project Hindsight translations, discussed more fully under the Arabic parts, were instrumental in reviving the wider Hellenistic doctrine of lots beyond the Part of Fortune alone for English-language readers in the 1990s; before that revival most twentieth-century Western astrology retained only Fortune, calculated with the day formula applied unreversed at all times, from what had once been a much larger and sect-sensitive Hellenistic technical apparatus.