17 August 2027 Lunar

Penumbral lunar eclipse, 17 August 2027

Visible from the Pacific, the Americas.

The Moon misses Earth's inner shadow entirely and passes through the faint outer one. It is a subtle shading on one limb rather than an event — the kind of eclipse you can look straight at and not notice. NASA gives the umbral magnitude as -0.525: the fraction of the Moon's diameter inside Earth's inner shadow at maximum.

Everywhere on this face of the Earth sees the faint outer shadow at the same moment — a lunar eclipse has no path across the ground, because the shadow is falling on the Moon rather than on us. All that changes from place to place is how high up it happens, and the rings are that: at the rim the Moon is rising or setting, at the centre it is straight overhead. This is also the night side of the planet, necessarily, since a full Moon is opposite the Sun. Drawn for 07:14:59 UT, the moment of greatest eclipse; the Earth turns about fifteen degrees an hour under it, so somewhere near the rim the Moon rises or sets partway through.

Safe to look at with anything or nothing: a lunar eclipse is just the Moon in shadow, and there is no Sun involved at your end of it. Binoculars help, and are the most equipment anybody needs.

Greatest eclipse: 07:14:59 UT
Type: Penumbral lunar eclipse
Umbral magnitude: -0.525
Moon that night: 100% lit, as it must be

Date, time and magnitude: NASA, Five Millennium Canon of Lunar Eclipses (opens in a new tab). Angular sizes and the Moon's distance computed here, for 07:14:59 UT.

The globe is computed here: the Moon's position for 07:14:59 UT gives the point it is overhead, and everywhere within ninety degrees of that has it above the horizon. Being a hemisphere rather than a narrow track, nothing here turns on the last kilometre. Coastlines: Natural Earth 1:110m, public domain.

Penumbral lunar eclipse, 17 August 2027

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