A penumbral lunar eclipse will occur at the Moon’s descending node of orbit on Wednesday, February 21, 1951,[1] with a penumbral magnitude of 0.007. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A penumbral lunar eclipse occurs when part or all of the Moon's near side passes into 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 about 6.5 days after apogee (on February 15, 1951, at 9:35 UTC), the Moon's apparent diameter was smaller.[2]
This eclipse was the first of four penumbral lunar eclipses in 1951, with the others occurring on March 23, August 17, and September 15.
Grazing penumbral eclipse
The magnitude of the eclipse was 0.007 or a miss depending on definitions of the penumbral shadow is defined. Bao-Lin Lui's Canon of lunar eclipses list it as the last eclipse of a saros cycle, with magnitude 0.007, while NASA lists February 10, 1933, as the final series event, with this one missing the shadow.[3]
As seen from the lunar south pole the sun missing the sphere of the earth, excluding the atmosphere.
Visibility
The eclipse was completely visible over Africa, Europe, and much of Asia.
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. The first and last eclipse in this sequence is separated by one synodic month.
The Metonic cycle repeats nearly exactly every 19 years and represents a Saros cycle plus one lunar year. Because it occurs on the same calendar date, the Earth's shadow will in nearly the same location relative to the background stars.