Look alive, people. This weekend will see the first and only “proper” supermoon of 2017, as the Moon reaches its full phase at the same time that it’s closest to Earth.
The Moon will be completely full at 10.47am EST (3.47pm GMT) on Sunday, December 3, and it will reach its closest point to Earth – known as perigee – the following day on Monday, December 4. That will put it 357,492 kilometers (222,135 miles) from Earth.
On the East Coast US, the full Moon will rise at about 4.59pm, so you should be able to spot it pretty early on when night falls as the Sun will set half an hour earlier. It won’t set again until 7.50am the following day, giving you plenty of time to observe it. It’ll still look essentially full the night before and after, too.
We’ve technically had three other supermoons this year, but the others involved a new Moon (when the Sun shines on the far side of the Moon) rather than a full Moon. The “new Moon supermoons” came in April, May, and June. This weekend, however, will be the first one that you can really see.
If you don't get a chance to see it, you can watch online at the Virtual Telescope Project.
Supermoons aren’t normally as amazing as they're made out to be. The Moon is only slightly closer than normal, about 50,000 kilometers (31,000 miles), so it will only appear about 14 percent bigger and 30 percent brighter – barely noticeable to the naked eye.
But it will still look pretty impressive, and if you spot it near the horizon it will look especially large, thanks to an optical illusion. Plus, the Moon’s proximity to Earth during this phase means that tides on Earth will be slightly larger than usual.
Like buses or something, we’re actually in for a bit of a supermoon extravaganza. After the full Moon on December 3, the full moons of January 2 and January 31 will technically be supermoons too. Nice!
I’ve definitely written the word “Moon” too many times now. Anyway, make sure you check out our lunar companion on Sunday evening. It might not look that different than normal, but a full Moon by itself is still pretty cool. This one will just look slightly more impressive.