ARI SHAPIRO, HOST:
Well, it's a marvelous night for a moon glance. Van Morrison and other stargazers might notice that the moon looks a bit bigger tonight for a blue supermoon.
AILSA CHANG, HOST:
That's right. It's a combination of two celestial events - a supermoon, when it's closest to Earth, and a blue moon, which is the third of four full moons in a season.
SHAPIRO: While we get supermoons a few times a year, blue supermoons are much more rare. This only happens about once per decade usually.
CHANG: Yeah. And we were actually fortunate enough to have a blue supermoon last August, too, Ari. NASA says today's supermoon technically hit its peak this afternoon, but it will appear full for three days.
SHAPIRO: The difference is subtle, but if you are chasing the best view, break out those binoculars and try checking out the moon as it's rising or setting in your area. Here in Chicago, as it was coming up over Lake Michigan last night, it looked deep red.
CHANG: Oh, cool. Do not miss this. The next seasonal blue supermoon, that may look red, won't happen until 2032. After all, you know, this kind of thing only happens once in a...
SHAPIRO: No, Ailsa. Ailsa, don't say it. Don't say it.
CHANG: ...Oh, please let me - blue moon.
(SOUNDBITE OF VAN MORRISON SONG, "MOONDANCE") Transcript provided by NPR, Copyright NPR.
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