Total Eclipse of the Moon

January 20, 2000

	The Moon has entered the umbra, the dark shadow of the Earth. The circular outline of the shadow was in ancient times powerful evidence that the Earth is a sphere.
As the Moon enters deeper into the umbra, the circular outline of the shadow becomes even more pronounced.
	The Moon is almost immersed in the umbra, and only a sliver of the bright lunar disk is left. The eclipsed portion of the Moon is red from sunlight playing off the Earth's atmosphere and lighting the shadow.
The Moon has just entered totality. The variation in the brightness of the shadow is obvious, the Moon much brighter at the shadow's western edge (upper right) than toward its center.
	Central eclipse. The Moon passed south of the center of the shadow, so the northern portion of the Moon, closest to the center, is the darkest. As the Moon moves through the umbra, the brightest portion of the shadow swings to the left.
The Moon is now about to leave the umbra, so the eastern edge of the still-eclipsed Moon is now quite bright.
	The Moon has now left the umbra and the circular outline of the shadow is again very prominent.