Hot on the heels of the year’s first solar eclipse — a partial eclipse on April 30 — a total lunar eclipse is on the horizon.
Between the late evening of May 15 and the early morning of May 16, depending on your time zone, the full Flower Moon will enter Earth’s shadow, causing a total lunar eclipse that will be visible from the majority of the Americas and Antarctica, as well as the western reaches of Europe and Africa and the eastern side of the Pacific. Skywatchers in New Zealand, eastern Europe and the Middle East will experience a penumbral eclipse, during which only the edge of Earth’s shadow falls over the moon.
According to TimeandDate.com, the partial eclipse will begin on May 15 at 10:28 p.m. EDT (0228 GMT on May 16), reaching its maximum on May 16 at 12:11 a.m. EDT (0411 GMT). That total eclipse effect can give the moon a reddish hue known as a Blood Moon. It will conclude at 1:55 a.m. EDT (0555 GMT). The penumbral eclipse will begin about an hour earlier and end about an hour after the partial eclipse.
Related: Lunar eclipses: What are they & when is the next one?
Lunar eclipses always happen during full moons. Full moons occur when the moon is on the opposite side of the Earth from the sun — the sun then illuminates the entire face of the moon as seen from the perspective of Earth. Because the moon’s orbit is tilted about 5 degrees compared to the Earth’s orbit, the moon usually avoids the Earth’s shadow; a lunar eclipse occurs when it doesn’t.
There are three types of lunar eclipses: penumbral, partial and total. In a penumbral eclipse, the moon passes through the outer part of the Earth‘s shadow, which is quite diffuse, so there’s only a slight dimming of the surface of the moon. A partial eclipse is when part of the moon enters the Earth’s darkest shadow, or the umbra, causing some of the moon to darken significantly.
And a total eclipse, as one might have guessed, is when the entire moon enters the darkest part of Earth’s shadow. A total eclipse will also include both penumbral and partial phases as the moon makes its way into the umbra. The upcoming lunar eclipse on May 15–16 will be a total lunar eclipse, although some locations will miss stages while the sun is above the horizon.
During total lunar eclipses, the moon often appears blood red. This is because light from the sun refracts around the Earth as if the planet were a prism; the light waves are stretched out, so they appear on the redder side of the spectrum when they reach the moon. The color is also influenced by the condition of Earth’s atmosphere; the moon can appear more orange or gold, depending on the amount of dust, cloud coverage or volcanic ash there is in the air.
If you miss this total solar eclipse, don’t worry — there’s another happening later this year on Nov. 8. That one will be visible across the Americas, Oceania and Asia.