A partial lunar eclipse occurred at the MoonâÂÂs descending node of orbit on Monday, December 10, 1973, with an umbral magnitude of 0.1007. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. Occurring only about 21 hours before perigee (on December 10, 1973, at 22:20 UTC), the Moon's apparent diameter was larger.
This eclipse was the last of four lunar eclipses in 1973, with the others occurring on January 18 (penumbral), June 15 (penumbral), and July 15 (penumbral).
The eclipse was completely visible over much of North and South America, Africa, Europe, and west and north Asia, seen rising over western North America and the eastern Pacific Ocean and setting over southeast Africa and much of Asia.
Shown below is a table displaying details about this particular lunar eclipse. It describes various parameters pertaining to this eclipse.
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros). This lunar eclipse is related to two partial solar eclipses of Solar Saros 122.