penumbral lunar eclipse

Penumbral lunar eclipse of 17 August 2027

The Moon passes through Earth's shadow at 07:13 UTC. This is a penumbral eclipse: the Moon only crosses the outer, partial shadow, so the effect is a subtle dimming rather than a visible bite out of the disc. Many penumbral eclipses pass unnoticed.

Duration

Penumbral half-duration

109.8 min

Half-durations are measured from greatest eclipse, so the full phase lasts twice as long.

Why eclipses come in seasons

The Moon's orbit is tilted about 5° to the ecliptic, so at most new and full moons it passes above or below the alignment. An eclipse needs the syzygy to coincide with the Moon being near one of the two nodes where the orbits cross. At this eclipse the Moon's ecliptic latitude was 1.149° — close enough to zero for the shadow to connect.

Times computed from VSOP87 and an ELP-derived lunar theory, validated against NOVAS and JPL Horizons to within one arcminute. See the alignment for yourself in the live simulation.