It’s not often the scientists at NASA wax poetic, but the total lunar eclipse expected late Monday night is reason enough for an exception.

For 72 minutes of eerie totality, an amber light will play across the snows of North America, throwing landscapes into an unusual state of ruddy shadow.

That’s the description NASA gives when describing what’s arguably the biggest sky-watching event of 2010. It will start in the last hours of Monday night on the west coast, beginning its partial eclipse at 10:33 p.m. The total eclipse will start at 11:41 p.m.

The eclipse will be visible in most of the norther hemisphere, a fairly common winter-time event that’s repeated three times in the last 10 years. But this year, there’s something special going on.

For the first time since 1638 — 372 years ago — the eclipse is aligned with the winter solstice.

Unless cloud coverage obscures the event late Monday night, viewers can expect quite a show. The full moon will pass through Earth’s shadow, changing from gray to a rusty, red color.

Why red? NASA describes it this way:

A quick trip to the Moon provides the answer: Imagine yourself standing on a dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down, completely hiding the sun behind it. The eclipse is underway. You might expect Earth seen in this way to be utterly dark, but it’s not. The rim of the planet is on fire! As you scan your eye around Earth’s circumference, you’re seeing every sunrise and every sunset in the world, all of them, all at once. This incredible light beams into the heart of Earth’s shadow, filling it with a coppery glow and transforming the Moon into a great red orb.

If you’re not much for staring at the sky, at least glance up once: early Tuesday morning at 12:17 a.m. That’s when the eclipse will be most striking, according to astronomers.

Wondering if you’ll be able to see the event through the clouds? Check out weather info and alternative viewing options here.

There’s more about how eclipses happen at shadowandsubstance.com. For more about the stages of the eclipse, read this story.