Data Sources
Data Sources
How we calculate lunar data and Void-of-Course periods.
Methodology
This page explains the astrology rules we use to label the Moon’s sign changes, Void-of-Course windows, and the four major lunar phases.
- Moon sign ingresses: computed from the Moon's ecliptic longitude crossing 30° boundaries.
- Void-of-Course: last exact major aspect (0°, 60°, 90°, 120°, 180°) the Moon makes to Sun/Mercury/Venus/Mars/Jupiter/Saturn/Uranus/Neptune/Pluto before the next sign ingress; VoC runs from just after that aspect until ingress.
- Major lunar phases: the New, First Quarter, Full, and Last Quarter Moon correspond to the Sun–Moon angle reaching 0°, 90°, 180°, and 270°.
Note: Different astrologers use slightly different VoC rules (for example, restricting to traditional planets). This site uses major aspects to the planets listed above to define the Moon’s “last aspect” in a sign.
Where the data comes from
The calendar times on this site are calculated from an astronomy ephemeris (a standard reference used by many astrology tools), then saved as fixed timestamps. In other words: the site isn’t “guessing” in real time — it’s displaying precomputed lunar timings.
- VoC intervals are derived from the Moon’s last major aspect in a sign (per the rules above) through the next sign ingress.
- Moon sign ingresses are derived from the Moon entering a new zodiac sign.
- Phase times are derived from the Sun–Moon angle reaching the quarter points (New/First Quarter/Full/Last Quarter).
These timings are published in UTC and shown in your selected timezone on the site.