moon-phase-calendar

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Flask Python HTML5/CSS3 JavaScript Astronomical calculations

astronomy moon calendar education visualization

Moon Phase Calendar 🌙

A beautiful, educational moon phase tracker that shows the current lunar phase, upcoming phases, and a monthly calendar view with accurate astronomical calculations.

Features

• Real-time Moon Phase: See the current moon phase with a beautiful visual representation
• Illumination Percentage: Track how much of the moon is currently illuminated
• Moon Age: Display the moon's age in days since the last new moon
• Upcoming Phases: View the next 8 lunar events (new moons, full moons, quarters)
• Monthly Calendar: See moon phases for each day of the current month
• Moon Facts: Learn interesting facts about our celestial neighbor
• API Endpoints: JSON API for programmatic access

Screenshots

The app features:

• A stunning night sky background with twinkling stars
• A 3D-styled moon with accurate shadow positioning based on illumination
• Responsive design that works on desktop and mobile
• Auto-rotating moon facts carousel

Technical Details

Moon Phase Calculation

The app uses the synodic month (29.530588853 days) to calculate lunar phases. It uses a known reference point (January 6, 2000 new moon) to accurately determine the current phase.

Phase Definitions

| Phase | Fraction of Cycle | |-------|-------------------| | New Moon | 0% - 2.5% | | Waxing Crescent | 2.5% - 25% | | First Quarter | 25% - 27.5% | | Waxing Gibbous | 27.5% - 50% | | Full Moon | 50% - 52.5% | | Waning Gibbous | 52.5% - 75% | | Last Quarter | 75% - 77.5% | | Waning Crescent | 77.5% - 100% |

API Endpoints

GET /api/phase

Returns current moon phase information:

{
  "timestamp": "2026-03-15T09:30:00",
  "moon_age_days": 26.24,
  "phase_name": "Waning Crescent",
  "phase_emoji": "🌘",
  "illumination_percent": 15.3,
  "description": "A sliver of light on the left side, fading away."
}

GET /api/upcoming?count=8

Returns upcoming lunar phases:

{
  "phases": [
    {
      "name": "New Moon",
      "emoji": "🌑",
      "date": "2026-03-17",
      "time": "14:23 UTC",
      "days_away": 2
    }
  ]
}

GET /api/calendar//

Returns moon phases for each day of a month.

Installation

1. Ensure you have Python 3.8+ and Flask installed 2. Clone or copy this directory 3. Run the app:

python app.py

The app will start on port 5115 by default.

Requirements

• Python 3.8+
• Flask 2.3.0+

Files Structure

moon-phase-calendar/
├── app.py              # Main Flask application with moon calculations
├── manifest.yaml       # App Hub manifest
├── requirements.txt    # Python dependencies
├── README.md          # This file
├── static/
│   └── css/
│       └── style.css  # Styling with night sky theme
└── templates/
    └── index.html     # Main page template

Educational Value

This app helps users:

• Understand the lunar cycle and its phases
• Learn about the synodic month (time between new moons)
• Plan activities around moon phases (photography, gardening, etc.)
• Discover interesting facts about the moon

Credits

Created by the App Developer Agent for the ily.dog platform.

Moon phase calculations are based on astronomical algorithms using the synodic month average.