Moon Phases API

Get real-time moon phase calculations with illumination percentage, phase angle, moon age, distance, and crescent visibility detection. Pure Go implementation using Meeus-style astronomical algorithms.

Get Moon Phase Data

Retrieve moon phase information for a specific location and date.

GET/v1/moon

Query Parameters

Name	Type	Required	Description
lat	float	Required	Latitude (-90 to 90)
lng	float	Required	Longitude (-180 to 180)
date	string	Optional	Date in YYYY-MM-DD format (default: today)
tz	string	Optional	IANA zone or documented alias — see Timezones. Omit or empty → auto-detect from lat/lng; invalid values may fall back to auto-detect.

Example Request

curl "https://api.falakapi.com/v1/moon?lat=21.4225&lng=39.8262" \
  -H "X-API-Key: fak_your_api_key_here"

Example Response

{
  "date": {
    "gregorian": "2025-01-15",
    "timestamp": 1736899200
  },
  "moon": {
    "phase_name": "Waxing Crescent",
    "phase_angle": 45.5,
    "illumination": 0.23,
    "age_days": 3.8,
    "distance_km": 384400,
    "is_crescent_visible": true,
    "emoji": "🌒"
  }
}

Notes

•Phase angle ranges from 0° (New Moon) to 360°
•Illumination is a decimal from 0.0 (New Moon) to 1.0 (Full Moon)
•Crescent visibility considers atmospheric conditions and moon position
•Distance is calculated in kilometers from Earth's center
•Optional tz accepts IANA names or documented aliases (Supported timezones /timezones); omit to auto-detect from coordinates

Moon Phases

Phase	Emoji	Description
New Moon	🌑	Moon is not visible
Waxing Crescent	🌒	Crescent visible, growing
First Quarter	🌓	Half moon, right side lit
Waxing Gibbous	🌔	More than half, growing
Full Moon	🌕	Fully illuminated
Waning Gibbous	🌖	More than half, shrinking
Last Quarter	🌗	Half moon, left side lit
Waning Crescent	🌘	Crescent visible, shrinking