An eclipse of the Moon is either total in which case our satellite is completely immersed in the Earth’s dark inner shadow (the umbra)—or it is partial meaning that only part of the Moon is covered. But this month, we have a very unusual situation involving a judgement-call between these two events!
On the morning of November 19th shortly after midnight, partial eclipse begins as the Moon enters the umbra at 2:19 a.m. EST. Maximum immersion occurs at 4:03. Partial eclipse finally ends at 5:47, as the Moon leaves the umbra. The entire spectacle will last just under 3 and a half hours. How close will it be for the eclipse actually being a total one—at maximum immersion 97% of the Moon with be covered. That 3% sliver of light remaining outside the umbra at the Moon’s southern (bottom) edge makes this officially a partial eclipse! It’s doubtful that this tiny bit of moonlight will be discernable to the unaided eye but should be visible in binoculars. These glasses are the ideal instrument for watching eclipses with their wide fields of view—much more so than the limited fields of typical telescopes.
As an aside, the Earth actually had two shadows extending out into space—the dark inner umbra discussed above and a very pale large outer one called the penumbra. The Moon slightly dims upon entering it and so for those who might like to try detecting it, our satellite enters it at 1:02 a.m. EST and finally leaves it at 7:04 (the Moon already having set for some readers).
Incidentally, a total solar eclipse will happen two weeks later on December 4th but will only be visible from Antarctica and the southern Atlantic Ocean. Also, the very weak Taurid meteor shower will occur on the night of November 4th to 5th under dark skies, the Moon being new, while the famed (but highly unpredictable) Leonid meteor shower happens on the night of Nov 17th to 18th. Unfortunately, the nearly full Moon will essentially wipe out the display this year.
— James Mullaney
Former assistant editor at Sky & Telescope magazine & author of 10 books on stargazing. His
latest, Celebrating the Universe!, is available from HayHouse.com.