Instrument
Moon Phase Calculator
Pick any date between 1700 and 2400, add a location, and drag the scrubber to watch the moon wax and wane. Every figure is computed live in your browser.
Clock
Position
17 September 2026 at 00:05 UTC
Phase
Waxing Crescent
- Illumination
- 32.7%
- Age
- 5.9 days
- Elongation
- 69.6°
- Direction
- Waxing
- Distance
- 401,345 km
- Distance (mi)
- 249,384 mi
- Apparent size
- 29.8′
- Constellation
- Sagittarius
- Libration lat
- 6.8° N
- Libration lon
- 3.1° E
Moonrise & moonset
Choose a location above to see moonrise, moonset and the peak altitude — these depend on where you are, unlike the phase itself.
Next principal phases
| Phase | Date | Time (UTC) | From selected |
|---|---|---|---|
| First Quarter | 18 September 2026 | 20:44 | tomorrow |
| Full Moon | 26 September 2026 | 16:49 | in 9 days |
| Last Quarter | 3 October 2026 | 13:25 | in 16 days |
| New Moon | 10 October 2026 | 15:50 | in 23 days |
Questions
- How accurate is this moon phase calculator?
- Positions come from the VSOP87 and ELP2000-82B theories, which agree with JPL Horizons to roughly one arcminute. Phase times are accurate to within a minute or so for any date between 1700 and 2400.
- Why do moonrise and moonset need my location?
- The phase of the moon is the same everywhere on Earth at a given instant, because it depends only on the sun-earth-moon geometry. Rise and set times depend on where you are standing, so they need a latitude and longitude.
- What is lunar libration?
- The moon keeps one face toward Earth, but its elliptical, tilted orbit makes that face appear to rock slightly north-south and east-west over the month. This is libration, and it lets us see about 59% of the lunar surface over time rather than 50%.
- What does the lunar age mean?
- Lunar age is the number of days elapsed since the last new moon. A full cycle — the synodic month — averages 29.53 days, so an age of about 14.8 days corresponds to a full moon.