Decreasing in Light

greek: μειούμενος τῷ φωτί (meioumenos tō phōti) — waning in light · latin: lumine decrescens

Definition

Decreasing in light describes the phase of the Moon — and by extension other bodies in their illumination cycle — between full and new, during which visible illumination diminishes. The classical Western tradition treats this waning phase as one of the canonical conditions modifying the Moon's interpretive weight, paired with its complement 'increasing in light' for the new-to-full half of the cycle.

In Tradition

Across the Hellenistic-Arabic-Latin lineage, the Moon decreasing in light is read as a condition of weakened or withdrawing luminary force. Dorotheus in *Carmen Astrologicum* Book 1 Ch 1.12 §§8-10 treats the Moon's increasing/decreasing light together with her latitude as joint modifiers of natal indicators for upbringing and way of life. The doctrine carries forward into Lilly's *Christian Astrology* (1647) under the same English label, where it bears particularly on horary judgment of loss, recovery, and matters that are diminishing.

In Practice

Traditional practitioners check whether the Moon is decreasing in light when reading any chart in which she serves as a primary significator. In horary work, the Moon decreasing in light supports judgments of decrease, loss, things passing from sight, or matters drawing to a close. In natal practice, Dorotheus reads a decreasing Moon in aspect with Mars or Saturn as 'no good in way of life,' while a Moon increasing in light and crossing into northern latitude is read as the peak indicator — Dykes's translation describes such a Moon as 'the most excellent she can be,' rising up toward the north. In electional astrology, applications begun under a decreasing Moon are traditionally read as more suited to matters of completion, dissolution, or release than to undertakings expected to grow.

Historical Origin

The doctrine is documented in Dorotheus's *Carmen Astrologicum* Book 1 Ch 1.12 (1st c. CE; surviving via ʿUmar al-Tabarī's Arabic translation), treating Moon-light-and-latitude as joint upbringing modifiers. The condition is preserved as a standard horary and natal qualifier in the medieval Arabic and Latin lineages and reaches Lilly's *Christian Astrology* Vol 1 (1647) in its English form.

Etymology

Origin: English. Meaning: Loss of illumination across a body's phase cycle.

Further Reading