(Crossposted to Jewschool.)
This year’s cosmic confluences march on! We’ve had the autumnal equinox on Rosh Hashanah, the winter solstice on Rosh Chodesh Tevet (during Chanukah), and Ice Cream for Breakfast Day on Tu Bishvat, and we’re still going to have the vernal equinox on Rosh Chodesh Nisan (in more westerly time zones), and Cheese Weasel Day on the first day of Pesach.
Tomorrow night, Purim will feature a total lunar eclipse!!!! (Both events always occur on the full moon, but obviously don’t happen every month.) Unlike a solar eclipse (where your view of the eclipse depends on your terrestrial vantage point, because the moon either casts a shadow on your part of Earth or it doesn’t), a lunar eclipse involves the Earth casting a shadow on the moon, so everyone on Earth sees the same thing at the same time (as long as they can see the moon).
The eclipse begins at 4:30 PM EST and ends at 8:11 PM EST. The maximum eclipse will be at 6:21 PM EST. (Add or subtract the appropriate number of hours for your own time zone.) Of course, you can only see the eclipse at the times when the moon is visible in the sky. Moonrise in NYC will be at 5:43 PM. You can look up moonrise for your location at this link. At this time of the month, moonrise should be close to sunset (since the full moon, by definition, is the time of the month when the sun and moon are on opposite sides of Earth). The moon (like everything else) rises in the east, so if you’re in the Americas (where the eclipse is happening in the early evening), you can look for it in the low eastern sky.
It is appropriate that this eclipse is happening on the night of Purim, while Jews in many parts of the world are reading the megillah. The Talmud (Sukkah 29a) says that a lunar eclipse is a bad omen for the Jews (who use a lunar calendar), and a solar eclipse is a bad omen for the nations of the world (who use solar calendars). (I’m not endorsing this scientifically!)
So what happens during a lunar eclipse? The moon gets covered up (bad for the Jews), and then becomes visible again (good for the Jews!). This exactly parallels the structure of the book of Esther: during the first half, it appears as though the Jews are going to be annihilated. In the end, this ominous darkness is chased away, and everything works out ok: LaYehudim hayetah orah vesimchah! The Jews had light and joy!