Per-minute precision · 100% offline

Read the moon.

Alarms for any moon phase, exact illumination, or astronomical moment. Lunar calendar, articles read out loud, and pattern detection from your daily logs. All offline, all on your device.

Free · No account · Offline
Lunar Cycles app — alarms screen
Scroll
8
Canonical phases
±1m
Precision
100%
Offline
10
Lunar events
Features

Everything you need.
Nothing you don't.

Phase alarms

Fire when the moon hits Full, New, First Quarter, Last Quarter, or any of the eight canonical phases. Optional advance days.

Illumination alarms

Want a reminder at exactly 73% waxing? The engine resolves the next crossing by bisection over a synodic cycle.

Astronomical moments

Blood Moon, Blue Moon, Harvest Moon, Supermoon, Micromoon, Eclipse Season. Each with its own countdown and astronomical detail. Computed locally with VSOP87 and ELP2000.

Listen to articles

Each article reads out loud through your device's voice. Pick voice and speed in settings. Offline, free, in any installed language.

Cards and home widget

Generate a moon card for today or any past date. Plus a home screen widget with today's moon, NASA texture, three sizes on Android.

Personal patterns

Log events across five categories and the app correlates them with phases over time. When a pattern emerges, it suggests an alarm.

Preview

See it in action

Ten screens of what the app actually does.

FAQ

Quick answers

Is Lunar Cycles really free?

Yes. The full app is free and ad-supported. An optional one-time premium purchase ($4.99) removes ads. There is no subscription.

What's the difference between a phase alarm and an illumination alarm?

Phase alarms fire on one of the eight canonical phases: New, Waxing Crescent, First Quarter, Waxing Gibbous, Full, Waning Gibbous, Last Quarter, Waning Crescent. Illumination alarms fire at any percentage you pick, like 73% waxing or 12% waning. The engine resolves the next time the moon will hit that target by bisecting the synodic cycle.

Which astronomical events does the app track?

Supermoon, Micromoon, Blue Moon, Black Moon, Harvest Moon, lunar eclipse (partial and total / Blood Moon), solar eclipse (partial and total), and eclipse seasons. Each one has its own countdown, peak time, and astronomical detail.

How does pattern detection work?

You log events from your day across five categories: physical, emotional, mental, sleep, behavioral. The app correlates each log with the moon phase it happened on. When three or more logs of the same type cluster on a single phase, the app suggests an alarm tied to that phase.

Can the app read articles out loud?

Yes. Each article has a play button that uses the text-to-speech voice installed on your device. You pick voice and speed in settings. It works offline, in any installed language, and costs nothing.

Does it work offline?

Yes. All ephemerides are computed locally. After install, the app does not need internet to work.

How precise are the alarms?

Within roughly one minute. The engine uses models derived from VSOP87 and ELP2000, the same families astronomers use for civilian-scale calculations.

Why do I need to whitelist the app for battery?

Aggressive battery savers on Android can kill background apps and prevent alarms from firing. Whitelisting Lunar Cycles ensures the alarm rings on time.

Ready to set your first alarm?

Free, offline, and precise. Install Lunar Cycles and create an alarm in under a minute.

Free · No account · Offline