Three decades have passed since the last time Earth was witness to the triple crown of lunar events — a full moon, a lunar eclipse, and a lunar perigee all at the same time — and now people in north America will be able to see a “supermoon eclipse” this weekend.
A lunar eclipse is when the Earth comes between the full moon and the sun. Although completely in the Earth’s shadow, the moon still receives a bit of reddish sunlight. Unlike a solar eclipse, there’s no special equipment needed to view it. A supermoon is when the moon is in perigee, or the closest point to the Earth it will reach. Sunday’s moon will be about 14% larger than normal, according to NASA.
There have only been five times since 1900 where the supermoon has coincided with a total lunar eclipse— and the next won’t happen for another 18 years.
Begin looking to the moon around 8 p.m. EDT on Sunday Sept 27, with the total eclipse setting in around 10 p.m. But if there’s cloud cover or you’re unable to get to a clear patch of sky then a livestream will be on TIME.com, hosted by Slooh. The stream will be hosted by Paul Cox and Bob Berman.