Stargazers are in for another beautiful display following Monday night's Aurora Borealis.
Tuesday (Sept. 17) evening will see a partial lunar eclipse coinciding with a harvest supermoon.
Jeroen Stil, Associate Professor in the Department of Physics and Astronomy at the University of Calgary, explains the nature of the eclipse.
"If people have seen a total eclipse, where the moon glows blood red, that's not quite what we'll get. We'll get only part of the moon turning dark, just 8.4 per cent of the surface."
That's not to say it won't be a beautiful sight, as we're also in for a supermoon.
"There are some things that make it extra nice. It is close to the horizon, so you'll need some free horizon to see it, but it's nice because you can see the moon with some foreground. The moon will appear bigger because it's close to the Earth. There's also an optical illusion when the moon is low, it will appear bigger. It will be quite a nice sight, even if it's just a small part of the moon, like a cookie with a very small nibble taken out of it," says Stil.
Luckily, partial eclipses are completely safe to view with the naked eye.
Stil explains the optical illusion behind supermoons.
"It appears so big because you see that astronomical object next to an everyday object. Your brain knows the size of a house or a tree, your brain doesn't really know the size of the moon. So your brain gets put a little off track by this thing that it knows next to this other thing."
The illusion can be broken, says Stil, by viewing the moon upside down.
It's also a harvest moon, being the full moon that appears closest to the autumnal equinox (Sept. 22).
The partial eclipse is expected to begin at 8:13 p.m., peaking at 8:44, and ending at 9:15.