Don’t miss the prettiest total eclipse

Almanac Weekly’s Night Sky columnist Bob Berman in his observatory in Willow (photo by Andrea Barrist Stern)

Almanac Weekly’s Night Sky columnist Bob Berman in his observatory in Willow (photo by Andrea Barrist Stern)

It’s very unusual that our region sees two total eclipses in a year. Such a double whammy happens only a few times a century.

The first 2014 event unfolds this Monday night, April 14. It starts with the strange voodoo word “penumbra,” which all by itself makes television anchors mess up their eclipse announcements. Consulting a reference book beforehand, they think that the action starts with the beginning of the penumbral eclipse, just before 1 a.m. Tip: Pretend “penumbral” spells out the word “zero.” Nothing happens. Each year I create the astronomy section of the Old Farmers’ Almanac, and I’ve made sure, since taking it over 20 years ago, that the “start” time of the eclipse ignores the penumbral portion. Otherwise, people go out, look up and wait – and wait some more, gazing at an ordinary Full Moon.

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So just skip ahead to 1:58 a.m. for the debut of the partial stage. Now the action begins. Since it’s after midnight, the date is April 15. Don’t get confused; when we say Monday night, we mean the wee hours of Tuesday morning.

The Moon is the only known body whose speed matches its diameter: It alone moves through space its own width each hour. No surprise, then, that it takes that long fully to enter Earth’s shadow. During this time, from around 2 to 3:06 a.m., the Moon goes through a bizarre series of odd shapes. Some resemble lunar phases, but most are much stranger than that.

Earth’s shadow tapers like a chopstick to roughly half its original width at the Moon’s distance – still about twice the moon’s size. So a lunar eclipse is a geometric wonderland involving curves with two different radii. These interacting curves produce their weirdest dreamlike effects when the shadow falls near the outer edge of the Moon, roughly at 2:15 a.m. and then again around 2:45 a.m. If you want to impress impatient beginners, have ‘em look up during these Times of Maximum Strangeness.

Totality starts at 3:06 and lasts until 4:25 a.m. During this time, the Moon usually turns coppery red. That’s because our planet throws a red shadow into space, in which the Moon has now become fully immersed. All the countless fainter stars that were masked by the Full Moon during the night’s first half now fill the sky. Although a total lunar eclipse is probably only one percent as wondrous as a total solar eclipse, it’s still very worth setting the alarm to see.

Lunar eclipses appear best through binoculars or just the unaided eye. The Full Moon is never a good telescope target, and hosting the blurry-edged shadow of Earth doesn’t help much. It’s not terrible, like macaroni salad; but Earth’s shadow edge is fuzzy, and fuzzy is not a good thing through an eyepiece.

This eclipse is particularly gorgeous. The eclipsed Moon hovers just above Virgo’s main star, Spica. Its blue dazzle will provide a striking contrast to the reddish Moon. Farther to the Moon’s right floats brilliant Mars, a distinct orange.

The event’s climax is a bit unpredictable, which adds to the fun. Although the Moon will probably turn red, some previous totalities have turned the Moon invisibly black, or brown, gray, red, coppery, orange or yellow/white, depending on the light reaching the Moon after skimming past Earth’s edge. This light varies with the amount of atmospheric dust, clouds, moisture and pollution around Earth’s limb. The lunar eclipse is thus the only celestial event where we look at another world but get an environmental report card about ourselves.

And if we don’t like what we see, hey, we get another chance on October 8. If it’s cloudy here, you can follow the eclipse live on your computer, at https://slooh.com.

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