Our mission
Most moon-phase sites are slow, ad-heavy, and track you across the web. We built Open Moon Calendar to be the opposite: a lightweight, accurate moon calendar that respects your privacy and works everywhere — on any device, in 10 languages, even offline.
What we offer
- Moon phases & full moon calendar for 2025, 2026 and beyond, with exact primary-phase times.
- Moonrise & moonset, sunrise & sunset computed for your exact location.
- Sun & Moon Today dashboard — live altitude curves, twilight phases, and horizon bearings.
- Night Sky & Eclipses trackers — upcoming solar and lunar eclipses with local visibility.
- 10 languages, day/night theme, offline mode — no login, no account, no paywall.
How it works
All astronomical calculations run 100% locally in your browser using well-established lunar algorithms (synodic cycle, SunCalc-style solar/lunar position math). Your location never leaves your device unless you explicitly choose it — there are no servers processing your coordinates, no analytics fingerprinting, and no advertising trackers bundled with the core experience.
Who maintains this?
Open Moon Calendar is an independent open web project, maintained by a small team of astronomy and web-performance enthusiasts. The site is static-first (built with Astro), which keeps it fast, cheap to run, and resilient under high traffic.
Get in touch
Found an inaccuracy, want a feature, or need to report an issue? We'd love to hear from you on our Contact & Feedback page. For data-use rules, see our Terms & Conditions and Privacy Policy.