If you’re up extra late tonight, you’ll notice something strange in the sky. The moon will turn red for about an hour during the lunar eclipse early Tuesday morning. The eclipse actually lasts for about three hours, starting at around 11:30 pm.

“Initially what you’ll see is; it looks like something is taking bites out of the moon as the shadow of the earth crosses it. Then when it gets completely dark, a second later as your eyes adjust, and all of the sunlight has been filtered through the atmosphere… Then it suddenly goes really red, and it should stay that way for about an hour,” said Angela Speck, the Director of Astronomy at the University of Missouri.

At about 1:30 am, the eclipse will reach totality and the moon will turn red for almost an hour. Speck says if you want to just wake up to get a quick glimpse of the eclipse, she recommends getting up around 2:00 am. But she also warns that cloudy conditions can block the moon completely from sight, so it might be a good idea to check the weather conditions in your area before setting your alarm clock.

This is the first time a lunar eclipse has happened on the same day as the winter solstice since the year 1638.  

Speck explains lunar eclipses actually happen every six months or so, but are only visible every year or year and a half because sometimes they happen during the day.  Speck says this is also an especially long eclipse because of the current position of the moon’s orbit around the earth.