About Phase of the Moon Today
Accurate, real-time moon phase data powered by proven astronomical algorithms
Our Mission
We provide accurate, accessible moon phase information for everyone - from amateur astronomers and photographers to gardeners and curious observers. Our goal is to make lunar data both scientifically rigorous and easy to understand.
Data Sources & Methodology
SunCalc Library
Our moon phase calculations are powered by the SunCalc library, which implements algorithms based on Jean Meeus's Astronomical Algorithms (2nd edition, 1998) - the authoritative reference for astronomical calculations.
This library is widely used and battle-tested across thousands of astronomical applications.
NASA JPL Horizons System
We validate our calculations against NASA's JPL Horizons System, the gold standard for solar system ephemeris data. Our moon phase calculations match NASA data to within 1 minute of accuracy.
Geographic Precision
Location-based calculations (moonrise, moonset) account for:
- Precise geographic coordinates (latitude/longitude)
- Local timezone and daylight saving time
- Atmospheric refraction effects
- Observer elevation (when available)
Accuracy & Precision
Moon Phase
Calculated in real-time using precise astronomical formulas. Illumination percentage accurate to 0.1%.
Moonrise/Moonset
Location-based times accurate to within 1-2 minutes, accounting for atmospheric conditions and geographic position.
Historical Dates
Moon phase calculations for any date from 1900-2100, validated against astronomical almanacs.
Update Frequency
Current moon phase updated in real-time. Location-based data refreshed every 24 hours.
Technology Stack
Built with modern web technologies for performance and reliability:
- Next.js 15 - React framework for optimal performance
- TypeScript - Type-safe calculations and data handling
- SunCalc - Astronomical calculation engine
- Docker - Containerized deployment for reliability
Editorial Standards
All content is fact-checked against authoritative astronomical sources:
- Astronomical calculations verified against NASA JPL data
- Educational content reviewed for scientific accuracy
- Blog posts cite peer-reviewed research where applicable
- Errors corrected promptly when identified
Privacy & Analytics
We respect your privacy:
- GoatCounter Analytics - Privacy-friendly, no cookies, GDPR compliant
- IP-based Location - Used only for initial location detection, not stored
- No Tracking - We don't track individual users or build profiles
See our Privacy Policy for full details.
Contact & Support
Questions about our methodology or found an error?
We're committed to accuracy and welcome corrections. While we don't have a contact form, you can report issues or suggest improvements through our feedback channels.
About This Project
Phase of the Moon Today launched in 2024 to provide free, accurate lunar data to anyone who needs it. Built with care and powered by proven science.