🌕 Moon Phases

Today’s Moon is Waning Crescent — 13% of the disk lit, day 26 of its 29.5-day cycle. The phase is computed from the synodic period against a reference new moon of 6 January 2000, 18:14 UTC, the same maths that drives Sky Tonight; dates below are mean phases and can sit up to about half a day from the exact moment.

The coming phase events

Full Moons of 2026

Why the Moon has phases

The Moon gives off no light of its own — it is a grey rock lit by the Sun, and what we see is the lit fraction as the three bodies change position. One half of the sphere is always bright; whether we see that half, the dark half, or a slice between depends on the Moon’s place in its orbit, which it completes relative to the Sun every 29.53 days. A waxing crescent in the evening western sky and a waning crescent in the morning east are the same geometry read from opposite sides of the month.

What each phase is good for

New Moon nights are the deep-sky season: no moonlight washing out galaxies and the Milky Way — plan trips by the table above. First and last quarter put the terminator (the day/night line) down the middle of the near side, where crater walls throw their longest, most dramatic shadows — the best nights at the eyepiece. Full Moon floods the whole near side with light, ideal for lunar maps and for Earthshine: the faint glow on the dark portion, sunlight bounced off our own planet onto the Moon and back.

Names worth knowing

The Harvest Moon is the full moon nearest the autumn equinox; because of the tilt of the Moon’s orbit it rises only minutes later each night for days around that full moon — historically light to finish the harvest, now a genuinely observable quirk of orbital geometry. Cultures kept their calendars by this disk for millennia, and several languages still say "month" and "moon" with one word.

Phase engine: local lunar maths (mean synodic period). For tonight’s twilight windows and what’s visible, see Sky Tonight; for the constellations behind the Moon, see Constellations.