Astronomical Lunar Calculator
Calculate precise lunar phases and positional data
Scientific Note: Lunar phases result from the Moon's orbit around Earth, with a synodic period of 29.53 days from new moon to new moon.
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-% illuminated
Age: - days
Lunar Events
Position Data
Lunar Phase Science
Lunar Phase Cycle
- New Moon: 0% illuminated (not visible)
- Waxing Crescent: Right side illuminated (1-49%)
- First Quarter: Right 50% illuminated
- Waxing Gibbous: Right 51-99% illuminated
- Full Moon: 100% illuminated
- Waning Gibbous: Left 51-99% illuminated
- Last Quarter: Left 50% illuminated
- Waning Crescent: Left 1-49% illuminated
Orbit Characteristics
Sidereal Period: 27.32 days
Synodic Period: 29.53 days
Mean Distance: 384,402 km
Orbit Eccentricity: 0.0549
Inclination: 5.145°
Angular Diameter: 29-34 arcmin
Perigee: ~363,300 km
Apogee: ~405,500 km
Lunar Observation Tips
Best Viewing Times
- First Quarter: Excellent for viewing craters along terminator
- Waxing Gibbous: Ideal for observing lunar maria
- Full Moon: Best for viewing bright ray systems
- Evening hours: Less atmospheric turbulence
Photography Advice
- Use tripod and remote shutter release
- ISO 100-400 for minimal noise
- Exposure: 1/125s for full moon, longer for crescents
- Shoot in RAW format for post-processing
Frequently Asked Questions
How accurate are these calculations?
Our algorithms provide moon phase timing accurate to within 0.5 days for 1900-2100. For professional astronomical work, consult precise ephemeris data.
Why does the Moon's size appear to change?
The Moon's elliptical orbit varies its distance from Earth by about 42,000 km between perigee (closest) and apogee (farthest), changing its apparent size by ~14%.
What causes lunar eclipses?
Lunar eclipses occur when Earth passes directly between the Sun and Moon, casting Earth's shadow on the Moon. This only happens during full moon when the Moon is near the ecliptic plane.