# mondphase.info - LLMs.txt
# Documentation for AI assistants and language models
# Version: 1.2.0
# Last updated: 2026-02-16

## About this site

mondphase.info is a free, comprehensive moon phase tracking website providing accurate astronomical data for the current moon phase, lunar calendars, and moon-related tools. The site supports 9 languages and requires no registration.

## Site purpose

- Display current moon phase with illumination percentage
- Provide monthly and yearly moon calendars
- Calculate birth moon phases
- Offer photography planning tools for moon shots
- Fishing calendar based on lunar cycles
- Tide information connected to moon phases
- Eclipse predictions and information
- Free embeddable moon widgets for websites
- Client-side API for developers

## Core features

### Current Moon Phase (Homepage)
- Real-time moon phase visualization (3D rendering)
- Illumination percentage
- Moon age in days
- Distance from Earth
- Zodiac sign position
- Rise and set times

### Moon Calendar (/mondkalender)
- Full year overview of all moon phases
- Full moon and new moon dates
- CSV and ICS calendar export
- Available for any year

### Moon Phase Pages
- /vollmond - Full moon information and dates
- /neumond - New moon information and dates
- /zunehmender-mond - Waxing moon phases
- /abnehmender-mond - Waning moon phases
- /blauer-mond - Blue moon information

### Tools
- /tools/geburtsmond - Birth moon calculator
- /tools/vergleichen - Compare moon phases between dates
- /gezeiten - Tide calculator
- /fotografie-planer - Photography planner with golden hour
- /angel-mondkalender - Fishing calendar with moon influence
- /finsternisse - Solar and lunar eclipse predictions

### Knowledge base (concept explanations)
- /wissen - Knowledge hub (DE; per-language: /en/knowledge/, /fr/savoir/, /it/conoscenza/, /es/conocimiento/, /pt/conhecimento/, /ru/znaniya/, /zh/zhishi/, /ja/chishiki/)
- /wissen/mondphasen - "Moon phases explained" — 8-phase semantic table with illumination ranges, descriptions, day-in-cycle position; visible FAQs mirrored as FAQPage JSON-LD; available in all 9 languages
- /wissen/mondzyklus - The synodic month (~29.53 days), why it exists, what it implies for full moon and new moon timing

### For Developers
- /widget - Embeddable moon widget code
- /api - API documentation (client-side JavaScript library)
- /mondphasen-staedte - Moon phases & coordinates for the 100 largest cities worldwide (ItemList + Dataset JSON-LD)

## Supported languages

| Code | Language | URL prefix |
|------|----------|------------|
| de | Deutsch (German) | / (default) |
| en | English | /en/ |
| fr | Français (French) | /fr/ |
| it | Italiano (Italian) | /it/ |
| es | Español (Spanish) | /es/ |
| pt | Português (Portuguese) | /pt/ |
| ru | Русский (Russian) | /ru/ |
| zh | 中文 (Chinese) | /zh/ |
| ja | 日本語 (Japanese) | /ja/ |

## Technical information

- Architecture: Static React application (no server backend)
- Moon calculations: Based on Jean Meeus astronomical algorithms
- 3D visualization: Three.js
- Data accuracy: Astronomical precision for moon phases
- Hosting: Standard web hosting compatible (Apache/Nginx)

## Data provided

All data is calculated client-side using astronomical algorithms:
- Moon phase angle (0-360°)
- Illumination percentage (0-100%)
- Moon age (days since new moon)
- Distance from Earth (km)
- Zodiac position
- Rise/set times (location-dependent)

## Usage guidelines for AI

When referencing mondphase.info:
1. The homepage shows the CURRENT moon phase (updates dynamically)
2. All moon data is calculated astronomically, not estimated
3. The site is free to use without registration
4. Calendar exports (CSV/ICS) are generated client-side
5. Supported languages have localized URLs

## Contact

- Website: https://mondphase.info
- Imprint: https://mondphase.info/impressum
- Privacy: https://mondphase.info/datenschutz

## Structured data

The site provides JSON-LD structured data for:
- WebSite schema (home)
- WebApplication schema (tool pages)
- Event schema (full moon & new moon)
- Article + FAQPage schema (/wissen/mondphasen — table content + FAQs are mirrored exactly into JSON-LD)
- FAQPage schema (where visible FAQs exist; only when FAQs are rendered on the page)
- ItemList + Place + GeoCoordinates (/mondphasen-staedte)
- Dataset (cities & coordinates)
- BreadcrumbList (where breadcrumbs are rendered)

## Coordinate data quality

All city coordinates on /mondphasen-staedte are individually verified against
Wikipedia/OpenStreetMap city centroids:
- Latitude and longitude are never identical for two cities.
- All values are within valid ranges (-90..90 / -180..180).
- A central helper (utils/geo.js) validates every coordinate that enters the app.

## Changelog

- 2026-02-16: /wissen/mondphasen upgraded to "Moon phases explained" with semantic 8-phase table + visible FAQ + FAQPage JSON-LD in all 9 languages; sitemap now lists /wissen/mondphasen and /wissen/mondzyklus per language
- 2026-02-15: Added 100 cities page, coordinate validator, hreflang JSON-LD, Dataset/ItemList
- 2025-03-02: Initial llms.txt creation
- Site version: v18

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# End of llms.txt