Increasing in Light

Definition

A planet is increasing in light when its lit face, as seen from Earth, is growing larger and it is becoming brighter night by night. This is one of a planet's accidental dignities — a strength from its condition rather than its sign. For the Moon it is the waxing half of the cycle, from New Moon to Full Moon. For Mercury and Venus it tracks their phase relative to the Sun; for Mars, Jupiter, and Saturn brightness builds through the cycle that peaks around opposition. The opposite, decreasing in light (waning), is a weakness.

In Tradition

Astrologers in the Hellenistic, Arabic-Persian, and traditional Western lines read increasing in light as a strengthening condition: the planet is gathering visible energy rather than losing it, so what it stands for is read as growing, building, or coming into expression. It matters most for the Moon, whose waxing-versus-waning state is one of the main accidental factors in horary, electional, and traditional birth-chart work. Lilly's Christian Astrology (1647) scores increasing in light +2 on the standard accidental-dignity tally.

In Practice

To work out a planet's phase, you measure its angular distance from the Sun and how fast that distance is changing. For the Moon the rule is simple: between New and Full she is waxing — increasing in light — and between Full and the next New she is waning. In horary, a question read from a chart, a waxing Moon supports growth, building, increase, and the success of fresh starts, while a waning Moon suits matters of decrease, reduction, withdrawal, and conclusion. Electional work, choosing a good moment to begin something, weighs the lunar phase against what is being started. In a birth chart a Moon increasing in light leans toward growth and expansion of the lunar themes, and for the other planets it colors the sense in which what they stand for is currently building.

Historical Origin

The increasing-versus-decreasing-light distinction appears in the Hellenistic technical writers Valens and Ptolemy and is preserved through the Arabic line and the medieval Latin tradition in Bonatti. Lilly's Christian Astrology (1647) gives the canonical English-language form with +2 / -2 accidental-dignity scoring. Sahl ibn Bishr at section 5.16 treats the "condition of the Moon" (li-l-qamar) as one of the sixteen planetary "accidents", grouping phase of light alongside void-of-course, combust, and the rest. Modern coverage appears in Lee Lehman's Essential Dignities.

Further Reading