Better Moon Phases

# Better Moon Phases Replaces Minecraft's default moon cycle (8 days, 8 single-day phases) with the **real synodic month of 29.530589 days**, adds **astronomically correct moonrise and moonset times**, and extends the **day duration to 1 real-world hour** (30 minutes of daylight and 30 minutes of night). If you are looking for deep astronomical immersion and a more realistic passage of time, this datapack is for you. It works flawlessly on multiplayer servers as well: the lunar phase is determined by the server and synced to all clients, requiring no client-side resource pack. !(https://cdn.modrinth.com/data/cached_images/0a24d2321869ad80a38ac6cd9c27011c1b913cdc_0.webp) *Note: Generative AI was used to assist with the creation of this datapack.* ## Installation 1. Drop `Realistic Moon Phase.zip` into `<your world>/datapacks/`. 2. Put `Realistic Moon Phase Resourcepack.zip` into `.minecraft/resourcepacks/` and enable it in Options > Resource Packs. On a server, either every player installs it or you set it as the server resource pack. 3. Join the world (or run `/reload`), then `/function realistic_moon:info`. On an **existing world**, the starting phase depends on how long the world clock has already been running. If you want to start from a specific phase, use `/function realistic_moon:phase/`. ## Commands | Command | Effect | | --- | --- | | `/function realistic_moon:info` | Shows current phase, cycle percentage, and time remaining until the next full moon | | `/function realistic_moon:phase/full_moon`* | Sets the Moon to the chosen phase without changing the time of day | | `/function realistic_moon:day_length/one_hour` | Sets 1 real-hour days (default) | | `/function realistic_moon:day_length/normal` | Restores the vanilla 20-minute day length | *Note: You can replace `full_moon` with any of the 8 available phases: `full_moon`, `waning_gibbous`, `third_quarter`, `waning_crescent`, `new_moon`, `waxing_crescent`, `first_quarter`, `waxing_gibbous`.* ## Statistics | Feature | Vanilla | Better Moon Phases | | --- | --- | --- | | **In-game Day** | 20 real min | **60 real min** | | **Lunar Cycle** | 8 days (2h 40m in-game) | **29.53 days (~29.5 in-game hours)** | | **Phase Duration** | 1 day (20 min) | **3.69 days (~3.7 hours)** | ⚠️ Combining high astronomical accuracy with 1-hour day lengths makes a full cycle take a significant amount of real-world time. To shorten it while preserving proportional accuracy, you only need to change **one number**: in `data/minecraft/timeline/moon.json`, update `period_ticks` (and scale the keyframe ticks by the same factor if you want phase windows to remain centered). | period_ticks | Cycle Length | With 1-Hour Days | | --- | --- | --- | | 708734 | 29.53 days | ~29.5 in-game hours (default setting) | | 354367 | 14.77 days | ~14.8 in-game hours | | 236245 | 9.84 days | ~9.8 in-game hours | Alternatively, you can leave the period realistic and restore normal day speed. Running `/function realistic_moon:day_length/normal` brings the total cycle to ~9h 50m of play time. ## Limitations - The lit limb points at the Sun along the Moon's path, which is what you see in the sky, but the Moon's disc does not counter-rotate the way it does in real life at high latitudes. There are no eclipses either: the game only knows eight phase images. - Night lighting changes are visual (`sky_light_factor`). Mob spawning light levels are untouched, so a dark new-moon night is not more dangerous than a full-moon one. - With 1-hour days each in-game day is three times more real time: crop growth, furnaces and mob build-up per day all triple, because they run on game ticks rather than on the world clock. - Overrides `data/minecraft/timeline/moon.json`, so it conflicts with anything else that edits that timeline or the `minecraft:visual/moon_angle`, `sky_light_factor` or `star_brightness` attributes. ## Compatibility * Requires **Minecraft Java 26.2** (data pack format 107). Incompatible with 1.21.x and earlier due to missing timeline features. * Overrides `data/minecraft/timeline/moon.json`: this will conflict with other datapacks modifying the same timeline or the `minecraft:visual/moon_angle` attribute. --- ## Roadmap (Future Updates) We are actively working on expanding the celestial mechanics of **Better Moon Phases**. Here is our vision for the future: * ✅ **Dark Moonless Nights:** Dynamic adjustments to nighttime brightness based on the lunar phase, making New Moons pitch-black and Full Moons bright. * **Expanded Version Support:** Expanding compatibility to support other popular Minecraft versions. * **Rare Celestial Events:** The introduction of Solar Eclipses blocking out the sun, and eerie Red Moons (Blood Moons) during the night. * **Complex Mechanics & Orbits:** Implementing inclined planetary rotations (axial tilt) to simulate true astronomical seasons. * **Visible Planets:** Adding accurately tracked, visible planet