Guides
Moon ephemeris — what the sky is about to do
The oldest page of any almanac is the one that looks forward. This one is computed the moment you open it, in your own time zone — the phases to come, the eclipses on their way, and the app's own rendezvous.
Facts checked 2026-08
What an ephemeris is
An ephemeris — from the Greek ephēmeros, “daily” — is the table at the heart of every printed almanac: for each date, what the sky will hold. Observatories publish theirs to the arc-second; a lunar almanac needs less and keeps the essentials — the instants of the principal phases, and the rare nights when the Earth's shadow crosses the Moon. That table is what you are reading above, computed rather than printed.
What this page carries
Three kinds of entries share the agenda. The full and new moons of the next four lunations, computed in your browser with the reference algorithms — each full moon linking to the story of its traditional name. The coming lunar eclipses, through 2029. And, when one is running, the current event in the Plenilune app — the same card the App Store shows, mirrored here word for word.
Questions
- What does “ephemeris” mean?
- From the Greek ephēmeros, “lasting a day”: a day-by-day table of where the celestial bodies stand. Plural: ephemerides. Every printed almanac is built around one; this page computes its lunar rows live instead of printing them.
- Are these times exact?
- The phase instants come from the standard algorithms (Jean Meeus, Astronomical Algorithms), accurate to the minute for decades around the present, and are shown in your time zone. Eclipse dates are given as the day of maximum in Universal Time — your local night can be the evening before.
- Where do the app events come from?
- They are the in-app events of Plenilune's App Store page, mirrored word for word from the same source file — nothing is written twice. When no event is running, the agenda simply shows the sky.