Watch Live: Partial Lunar Eclipse Darkens Moon’s Surface

This afternoon, the moon will dip into the Earth’s outer — or penumbral — shadow, creating an unusual and uneven shading across its surface. A live stream of this partial lunar eclipse from the Slooh Space Camera will begin at 2:45 p.m. PT/5:45 p.m. ET and should last a bit more than four hours.

The Earth casts two shadows: the umbra, the darkest region where light from the sun is completely blocked, and the penumbra, where some of the sun is obscured but the light from a few parts still reaches in. A total lunar eclipse happens when the moon enters the umbra, turning a dramatic red as the Earth’s atmosphere refracts the sun’s light, projecting only the longest wavelength colors on the moon. A partial lunar eclipse creates less freaky colors, instead leaving one part of the moon in full sunlight while the other side gets none. This results in a subtle gradient across its surface that often goes unnoticed.

Slooh will have its live feed from telescopes around the world to watch the show. The broadcast team fill in the penumbral lunar eclipse with live commentary starting at 4:30 p.m. PT/7:30 p.m ET. They will be around during the time of greatest eclipse, which should occur around 4:50 p.m. PT/7:50 p.m ET. The unusual shading will be most apparent when seen as a time-lapse, which Slooh will provide.

For all you night owls in need of some more astronomy, the folks at Slooh have another awesome night sky show ready as Comet ISON passes within close proximity of Mars. Starting at 10:30 p.m. PT/1:30 a.m. ET, they will have live feeds of the comet, which is headed toward the sun and, if it survives, could become one of the most spectacular objects in the night sky later this year. Comet ISON made its closest approach to Mars at the beginning of the month but the two objects will still be visible near one another tonight.