Moon Phase Calendar
Generate a precise visual calendar of lunar phases for any month. Includes illumination percentages and lunar age for photographers and astronomers.
Selected Day Details
About
Professional planning for night sky observation requires more than a rough guess of the moon's state. Photographers chasing the perfect Milky Way shot need total darkness, meaning a New Moon, while coastal engineers and fishermen track lunar cycles to predict tidal variance. This tool generates a detailed lunar calendar based on the Synodic Month, which averages 29.53059 days.
Accuracy is paramount when scheduling telescope sessions or deep-sky imaging. A discrepancy of just one day can mean the difference between a dark sky and one washed out by 90% illumination. This utility calculates the specific lunar age and illumination fraction for every day of the selected month, aiding in the precise timing of projects sensitive to natural light pollution.
Formulas
The calculation of the moon's phase relies on the Synodic month. The approximate age of the moon A in days since the last known New Moon is calculated using the date D and a reference epoch.
Where JD is the Julian Date. The illumination fraction k is derived from the phase angle i:
Reference Data
| Lunar Phase | Elongation (E) | Illumination | Visible Duration |
|---|---|---|---|
| New Moon | 0° | 0% | Rise/Set with Sun |
| Waxing Crescent | 0< E < 90° | 1-49% | Early Evening |
| First Quarter | 90° | 50% | Afternoon to Midnight |
| Waxing Gibbous | 90< E < 180° | 51-99% | Late Afternoon to Dawn |
| Full Moon | 180° | 100% | Sunset to Sunrise |
| Waning Gibbous | 180< E < 270° | 99-51% | Twilight to Morning |
| Last Quarter | 270° | 50% | Midnight to Noon |
| Waning Crescent | 270< E < 360° | 49-1% | Pre-dawn |