It's hard for our eyes to distinguish these small changes in size when the Moon is high amidst the vastness of the night sky.
Do you know at what phase a supermoon occurs?
The moon rose on Sunday and became totally full at 15.47 GMT, and was still visible this morning. It will be extra special. That often causes the moon to shine with a reddish hue, in what's known as a 'blood moon'.
While it may be hard for casual skywatchers to notice anything unusual about the supermoon, astrophotographers can really make the supermoon shine: Longer telephoto lenses can make the moon appear especially huge against a backdrop. "But it's another great chance to watch the Moon".
The Moon will lose its brightness and take on an eerie, fainter-than-normal glow from the scant sunlight, giving it a reddish hue. At 3.47pm yesterday - the exact moment of full moon - it was 222,761 miles from Earth, closer than the average distance of 238,900 miles. Those supermoons tend to occur when the moon is at its closest, often two or three months in a row.
There are interesting skywatching events every year, but 2017 has been particularly generous, with the eclipse drawing millions to peer skyward and plenty of cool moon action as well, but it's still not done.
Sometimes the celestial rhythms sync up just right to wow us.