Penumbral lunar eclipse to pass quietly March 24-25, 2024

Guy Ottewell originally published this post at his blog. Re-printed here with permission.

The first of this year’s four eclipses will flit by like a ghost in the night between March 24 and 25.

The moon arrives at full phase – opposite to the sun – more than 21 hours before descending southward across through the ecliptic (the sun-Earth plane). So it passes well north of the middle of Earth’s shadow, through the outer region called the penumbra, from within which the sun is not completely hidden.

The Latin phrase paene umbra means “almost shadow” or “scarcely a shadow.” As described in the “Lunar eclipses” section of The Under-Standing of Eclipses:

The penumbra is so light a shadow that it is hardly a shadow at all. Think how brilliant the Sun is: only a speck of it has to show to turn night into day. So it is not surprising that places on the moon from which most of the sun is visible look to us undarkened. Only the inner third of the penumbra may be perceptibly gray. Thus penumbral eclipses are hardly even noticed unless and until one edge of the moon dredges the inner penumbra. Then that edge becomes delicately stained.

If this eclipse can be seen at all, America is in the grandstand position, facing outward toward the moon. This also means that the eclipse begins on March 24 Universal Time and ends on March 25 .

The central moment, when the moon is nearest to the middle of Earth’s shadow, will occur when the moon is overhead for the Pacific west of Ecuador.

More photos of penumbral lunar eclipses

Bottom line: The first of this year’s four eclipses will flit by like a ghost in the night between March 24 and 25. It’s a penumbral lunar eclipse, visible in North America. Charts and more from Guy Ottewell here.

Via Universal Workshop