The moon is seen during a total lunar eclipse from New York, Tuesday, Dec. 21, 2010. A total lunar eclipse occurs when the Earth casts its shadow on the full moon, blocking the sun's rays that otherwise reflect off the moon's surface. Some indirect sunlight still pierces through to give the moon its red hue. (AP Photo/Seth Wenig)
A dusty red moon known as a "blood moon" will be visible throughout the Western Hemisphere early Tuesday morning, the first of four such lunar eclipses over the next year and a half.
The blood moon will appear during what is the first total lunar eclipse in two years.
A lunar eclipse comes only when a full moon aligns perfectly with the sun and Earth. During the eclipse, the Earth's shadow is cast across the moon, blocking the rays from the sun.
The moon turns red during an eclipse because the sunlight is refracted, similar to the way it is bent during a sunset.
Scientists say the eclipse will first appear dark gray and then turn red-orange.
For those in the tri-state area, the eclipse will begin at 1:58 a.m. Tuesday, and last for more than three hours. The best viewing time will be when everything is perfectly aligned, starting at 3:07 a.m., lasting 78 minutes.
Three other blood moons will be visible Oct. 8, April 4, 2015 and Sept. 28, 2015.
Lunar eclipses are safe to watch without protective wear, unlike solar eclipses.