NASA is urging skywatchers to head outside early on Jan. 31 for a look at what the space agency is calling a "lunar trifecta."

It's the rare combination of a blue moon (the second full moon in a single calendar month), a supermoon (a moon that's full when it's at its closest point in its slightly elliptical orbit around Earth), and a total lunar eclipse or "blood moon," in which Earth's shadow upon the lunar surface gives it a reddish tint.

What's the best time to view the supermoon?

In the continental U.S., the best views of this "super blue blood moon" will be in the West, Gordon Johnston, a NASA program executive who blogs about the moon from the agency's Washington, D.C. headquarters, said in a written statement.

"Set your alarm early and go out and take a look."