◐ Moon Phase Calendar: Every Phase, With Dates

Every Moon phase with real dates and the sign each one falls in, free. New Moons, Full Moons and everything between. It works as a plain astronomy calendar whether or not you read the astrology.

• What you'll needNothing: the same sky for everyone
• What you getEvery New and Full Moon with dates and signs, plus the phase for any date you pick
• CostFree, no account required

The Moon's cycle runs about 29.5 days from one New Moon to the next. At the New Moon it sits between us and the Sun and is invisible; at the Full Moon we're between the two and see the whole lit face. The quarters sit halfway between, showing a half disc.

Astrologically the cycle is most often used as a rhythm, not a cause. The New Moon is traditionally treated as a beginning, a natural checkpoint for choosing where your attention goes over the coming month, and the Full Moon as a culmination, where something started earlier becomes visible. It's a monthly cadence for intentional living that happens to be printed on the sky.

The sign a lunation falls in colours it. A Cancer New Moon reads differently from a Capricorn one. Umbriel shows both the date and the sign, along with which phase any date you pick fell in, useful if you're looking back at when something happened.

This tool shows the Moon's phase now, or at any moment you set, and the next eight principal phases: New Moon, First Quarter, Full Moon and Last Quarter. The phase is not looked up from a table of dates. Umbriel computes the Moon's and the Sun's longitudes for the instant, and the phase is the angle between them: illumination is (1 minus the cosine of that elongation) divided by 2, the eight named phases are 45-degree bands centred on 0, 45, 90 and so on, and the Moon counts as waxing while the elongation is under 180 degrees. Each upcoming phase is found by stepping forward in steps of about 29 minutes until the elongation crosses the next multiple of 90 degrees, then halving the interval until the moment is pinned, and the sign the Moon is in at that instant is reported with it. Times are shown in your device's own time zone. The Moon runs on a truncated ELP-2000/82 series, checked against NASA/JPL Horizons to 0.27 arcminutes over 1600 to 2050, and the Sun is within 1 arcsecond over 1650 to 2050. A phase time depends on those two positions only, so it does not depend on your birth data or place, only on the time zone used to display it. The planting and rhythm notes on the page are traditional readings attached to the phases, not measurements.