Eclipse Geometry

Why eclipses don't happen every month

Station Card (PDF)
NO ECLIPSE
Moon is 3.2° above ecliptic plane
View from Above
To Sun Ecliptic Node Node Earth
Drag the Moon around its orbit
Side View (Looking Along Ecliptic)
Ecliptic Sun Earth
Orbital Tilt 5.1°
0° (eclipse every month!) 10°
Earth–Moon Distance 384,400 km
Total vs annular depends on whether the Moon looks larger or smaller than the Sun.
Current Phase Full Moon
Moon Position 0°
0° (Full) 180° (New) 360°
Long-Term Simulation
Normal
Simulate Years 10
1 10 100 1000
Key insight: The Moon's orbit is tilted ~5° from Earth's orbital plane. This small tilt means the Moon usually passes above or below the Sun/Earth's shadow. Eclipses only happen when the Moon is near a node (where orbits cross) during new or full moon.
Model note: Conceptual model; ignores some real orbital details; results are approximate.
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