A solar eclipse and a lunar eclipse are opposite alignments — but every month has both a new moon and a full moon, and we don't get an eclipse at every one. Turn on the Moon's real tilt below to see why.
Interactive controls require JavaScript and WebGL. The scientific explanation and NASA sources below remain readable if the model is unavailable.
Oblique view: the raised Moon orbit shows why matching a new or full phase is not enough. The separate labeled side-view diagram below gives the exact conceptual explanation; no shadow-size prediction is made.
An eclipse requires a new or full moon near the tilted orbit's nodes. Change node orientation to test an alignment versus an orbital-plane miss. Node direction changes are meaningful only with tilt enabled; turn tilt off to compare the imaginary zero-tilt orbit.
Observation-angle controls are based on NASA eclipse geometry. They move the model camera only, not the Moon, real inclination (~5.1°) or nodes; no predicted eclipse shadow or observer-sky photograph is represented.
An eclipse needs new/full moon AND the Moon crossing Earth's orbital plane at one of two points called nodes. This model illustrates tilt at 15° instead of the real ~5.1° for visibility, but does not calculate the exact node-crossing timing.
Compressed like every model on this site — real eclipse geometry also depends on the Moon's and Sun's exact apparent size, which is why some solar eclipses are total and others are annular (a "ring of fire").
Why we only ever see one side of the Moon.
The everyday version of this alignment — no tilt, just phase shape.
Back to the full interactive 3D solar system.
