View larger. | Left, an ordinary full moon with no eclipse. Right, full moon in penumbral eclipse on November 20, 2002. Master eclipse photographer Fred Espenak took this photo when the moon was 88.9% immersed in Earth’s penumbral shadow. There’s no dark bite taken out of the moon. A penumbral eclipse creates only a dark shading on the moon’s face. Image via Fred Espenak. Used 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.
A penumbral lunar eclipse is subtle. Even at mid-eclipse, some will swear no eclipse is taking place. Other more observant people will notice the Earth’s shadow on the moon, especially at mid-eclipse. America is in the grandstand position to view the March 24-25, 2024, penumbral eclipse. We are facing outward toward the moon as the eclipse is taking place. This also means that the eclipse begins in March 24 by Universal Time and ends in March 25 (begins Sunday evening for the Americas and ends Monday morning). The central moment, when the moon is nearest to the middle of Earth’s shadow, happens when the moon is overhead for the Pacific west of Ecuador. Image via Guy Ottewell.
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.
If you go out around midnight at the end of March 25, with a clear sky, you should be able to see that the brilliant full moon is a slightly darker gray at its southern edge. Here is the moon among the stars at that time. Image via Guy Ottewell.
More photos of penumbral lunar eclipses
A full moon during a penumbral lunar eclipse with a slightly shadowed southeast curve. Image via NASA.A penumbral lunar eclipse on November 20, 2002 in Dunkirk, Maryland. Image via Fred Espenak.
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.
Astronomer, artist and poet Guy Ottewell's beloved Astronomical Calendar is back! Find the 2024 calendar here: https://www.universalworkshop.com/astronomical-calendar-2024/ And visit Guy’s website UniversalWorkshop.com or his blog at UniversalWorkshop.com/Guysblog. Guy's stories and art are used here with permission, and we are honored to have them. Thank you, Guy! The image shows Guy walking from the Carolina coast to the Blue Ridge mountains one spring (as depicted in Sky & Telescope magazine).
Like what you read? Subscribe and receive daily news delivered to your inbox.
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.