Remember to watch for the total lunar eclipse the morning of Wednesday, January 31.

Here in Manor, penumbral eclipse (Moon enters Earth’s penumbra) begins at 4:51am, partial eclipse (Moon enters Earth’s shadow) starts at 5:48am, and totality (Moon completely in Earth’s shadow) begins at 6:51am. The Moon will set while fully eclipsed at 7:20am. The Sun will dawn at the same time. A clear view of the west is best.

The most striking effect of a lunar eclipse is the deep red color of the Moon during totality. Why does it look red, instead of black?

If Earth were just a huge ball throwing shade (literally) on the Moon, the Moon would appear black. But Earth has an atmosphere all about. When backlit by the Sun, some sunlight passes through the layers of air, and some of this gets refracted (bent) and shine on the eclipsed Moon. Sunlight contains many colors; the shorter-wavelength blue colors get scattered about the planet (thus our sky looks blue), while longer-wavelength oranges and reds continue on away from Earth to cast dim, reddish light.

In fact, if you were on the Moon looking at Earth during a lunar eclipse, you would see the atmosphere as a reddish ring about an otherwise black Earth that blocks the Sun. That’s the source of the red glow. Jupiter, Mars, and Saturn are easily visible in the southeast before dawn. All three will be with us at least through end of summer. Day by day, Mars appears to be moving out of Libra (the Scales) into Scorpius (the Scorpion), towards Saturn. Mercury has set into the glare of the Sun. It will reappear, along with brilliant Venus, in the west by mid-March. Venus will continue to rise higher in the western evening sky throughout the summer.

Joseph Macry studied astronomy at UT Austin, and is a member of Austin Astronomical Society.