January 31 will bring a celestial event known as a blue moon, an occurrence that happens every two to three years. While interesting on its own, the real kicker is this blue moon will be the first lunar eclipse of a blue moon in nearly 150 years. Did we mention it’s also a supermoon? Here’s where you can watch it (and why the moon isn’t actually blue).
An Actual Blue Moon is Unpredictable
A blue moon, in this case, has nothing to do with its color, and everything to do with timing. There are normally 12 full moons a year, with a 13th “blue moon” showing up on average every two to three years. The combination of a blue moon and an eclipse, however, is pretty rare. The last total eclipse involving a blue moon occurred March 31, 1866.
Want to see an actually blue moon? You’ll have to wait for a particular set of unpredictable circumstances, usually involving volcanic eruptions or massive forest fires that release dust and smoke particles in the atmosphere. Depending on the size of the particles, the moon can sometimes appear blue—although it’s more common for it to look reddish.
How to Watch Outside
Stepping outside on January 31 won’t guarantee you a look at that lunar eclipse. The easternmost part of North America and the majority of South America will catch the tail end of the eclipse, with the moon dipping below the horizon at 6:48am EST. Sorry, Americans, but the lunar eclipse will be most easily seen on the other side of the planet.
If you want a good look at the blue moon eclipse, you’ll have to travel to the planet’s eastern hemisphere, and pick a spot somewhere in Australia, New Zealand, or eastern Asia. If you’d rather see it in one of America’s 50 states, you can choose between Alaska or Hawaii (Canada’s northwest region is also an option, if that’s what you’re into). You can take a look at NASA’s lunar eclipse chart to see where you’ll be able to catch the best view of the lunar eclipse, and where you’re guaranteed to miss it entirely.
How to Watch at Home
I don’t blame you for wanting to stay inside during the cold winter months, but you should still try to get a look at this literal once-in-a-lifetime event, even if it’s through your computer screen. You can watch a livestream of the upcoming eclipse thanks to The Virtual Telescope Project, or the robotic telescope streaming service Slooh. No matter where you are, taking a moment to appreciate the rare sighting of a blue supermoon lunar eclipse should be on your to-do list for 2018.