If you’re on the West Coast, watching tonight’s total lunar eclipse will require a willingness to stay awake in the middle of the night — plus a lucky break on the weather.
But maybe it’s worth taking a chance: The next opportunity to take in the sight of a blood-red, eclipsed moon won’t come until 2025. And even if it’s cloudy, you can hedge your bets by tuning in NASA’s live stream of the event.
Lunar eclipses occur when Earth and the moon are positioned such that our planet blocks out the sunlight falling on the lunar surface. During a partial eclipse, only a portion of the moon goes dark. Totality occurs when the moon passes directly through the darkest part of Earth’s shadow, known as the umbra.
The partial phase of tonight’s eclipse begins at 1:44 a.m. Tuesday, with totality lasting from 2:17 to 3:42 a.m. During the total phase, the only light falling on the moon’s near side will come from the reddish light refracted by Earth’s atmosphere. Put more poetically, it’s the light from countless sunrises and sunsets.