COUNTDOWN BEGINS FOR APRIL'S TOTAL SOLAR ECLIPSE. WHAT TO KNOW ABOUT WATCH PARTIES AND SAFE VIEWING

The sun is about to pull another disappearing act across North America, turning day into night during a total solar eclipse.

The peak spectacle on April 8 will last up to 4 minutes, 28 seconds in the path of total darkness — twice as long as the total solar eclipse that dimmed U.S. skies in 2017.

This eclipse will take a different and more populated route, entering over Mexico’s Pacific coast, dashing up through Texas and Oklahoma, and crisscrossing the Midwest, Mid-Atlantic and New England, before exiting over eastern Canada into the Atlantic.

An estimated 44 million people live inside the 115-mile-wide (185-kilometer-wide) path of totality stretching from Mazatlán, Mexico to Newfoundland; about 32 million of them are in the U.S., guaranteeing jammed roads for the must-see celestial sensation.

The eclipse will allow many to share in the “wonder of the universe without going very far,” said NASA’s eclipse program manager Kelly Korreck.

Sunglasses won’t cut it during the April 8 eclipse. Special eclipse glasses are crucial for safely observing the sun as the moon marches across the late morning and afternoon sky on April 8, covering more and more and then less and less of our star. (AP Video/Shelby Lum)

Here’s what to know about April’s extravaganza and how to prepare:

WHAT HAPPENS DURING THE TOTAL SOLAR ECLIPSE?

The moon will line up perfectly between the Earth and the sun, blotting out the sunlight. It will take just a couple hours for the moon’s shadow to slice a diagonal line from the southwest to the northeast across North America, briefly plunging communities along the track into darkness.

Fifteen U.S. states will get a piece of the action, albeit two of them — Tennessee and Michigan — just barely.