Moon
Phases of the Moon
A Moon phase tells us how much of its sunlit side is visible from Earth. The cycle repeats about once a month and does not prescribe what anyone should do.
Brief explanations help you read without specialist knowledge. Astrological terms describe a symbolic method, not scientifically established personality traits.
The Moon does not produce its own light — what we see is sunlight reflecting off it, and a phase is simply how much of the Moon's sunlit hemisphere is turned toward Earth at a given moment. That, in turn, depends on the angle between the Sun and Moon as seen from Earth (the elongation): at new Moon, the Moon sits close to the same direction as the Sun (elongation near 0 degrees) and its lit half faces away from us; at full Moon, it sits opposite the Sun (elongation near 180 degrees) and its lit half faces us fully. Between these, the familiar named phases — waxing crescent, first quarter, waxing gibbous, full, waning gibbous, last quarter, waning crescent — mark roughly equal steps around that angle. This is standard, agreed astronomy, published for example in the U.S. Naval Observatory's own phase tables, and computable from the same Sun and Moon positions this project's own ephemeris tracks.
The average time from one new Moon to the next — the synodic month — is about 29.53 days, slightly longer than the Moon's roughly 27.3-day orbit around the Earth, because the Earth itself is also moving around the Sun during that time. Because this is a geometric relationship, not a placement in the zodiac, it is unrelated to which sign the Moon or Sun happens to occupy — a full Moon can occur with the Sun and Moon in any pair of opposite signs.
Assigning meaning to a particular phase (a new Moon for beginnings, a full Moon for culmination, and so on) is a symbolic and cultural tradition layered on top of this geometry, not a further astronomical measurement — see "Calculation vs. interpretation" for how this project distinguishes the two.
The average time from one new Moon to the next — the synodic month — is about 29.53 days, slightly longer than the Moon's roughly 27.3-day orbit around the Earth, because the Earth itself is also moving around the Sun during that time. Because this is a geometric relationship, not a placement in the zodiac, it is unrelated to which sign the Moon or Sun happens to occupy — a full Moon can occur with the Sun and Moon in any pair of opposite signs.
Assigning meaning to a particular phase (a new Moon for beginnings, a full Moon for culmination, and so on) is a symbolic and cultural tradition layered on top of this geometry, not a further astronomical measurement — see "Calculation vs. interpretation" for how this project distinguishes the two.