Right OutsideUpdated Aug 23 · Calgary
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Lunar eclipse
Peaking · Night sky

The moon slides into Earth's shadow

Thursday night21:13 to 23:14

For a couple of hours the moon will pass behind the Earth, and you can watch it happen in real time. A dark curve creeps across the face of the moon, and the part it swallows doesn't go black: it turns a dull copper orange, staying lit the whole way through. What you are seeing is the Earth's own shadow, with our planet sitting between the sun and the moon, and it only ever happens on a full moon. The orange is the best part: it's every sunrise and every sunset on Earth at once, bent through the edge of our atmosphere and landing on the moon. Nothing to buy, nothing to set up, and no reason to look away.

A dark curve crossing the moon, and the covered part glowing orange rather than going black
The shadowed phase runs a couple of hours, so arriving part way through is fine
anywhere with a clear view southeast, no dark sky needed
Greatest at 22:14, when 93% of the moon is covered. Cloud is the only spoiler
SourcesEclipse elements computed from standard published algorithms (Meeus, Astronomical Algorithms ch. 54), cross-checked against the published eclipse canon
Photo: NASA/Joel Kowsky · public domain · via NASA
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