In the middle of the day, darkness falls. Birds stop singing. The sun’s corona pops out and shimmers across the sky. For two strangely-silent minutes, while the moon completely covers the sun, you’re spellbound inside the moon’s cool shadow. Then, suddenly, reluctantly, you’re free again–free for the rest of your life to jet around the world trying to catch another total eclipse.
Total eclipses are serious business. Partial eclipses, on the other hand, are just plain fun.
Get ready for fun. On Friday afternoon, April 8th, people in southern parts of the USA, all of Mexico and much of South America will experience a partial eclipse.
The sky won’t grow dark. Birds won’t stop singing. And the corona won’t make an appearance. During a partial eclipse of the sun, the moon covers only a fraction of the solar disk, taking a curved “bite” out of our star. The sun remains glaring-bright. If you don’t know it’s happening, you might not even notice.
But there is something to see: the shadows.
Look under a tree. Sunlight beaming through gaps in the leaves make crescent-shaped spots on the ground. Look around the walls of your home or office. You might see crescents projected by slits in the window shades. Windows with cut glass are even better. Their prism-sharp corners bend sunlight and cast rainbow-colored crescents in unexpected places. It’s like a treasure hunt.
You can make your own crescents. Lay your left hand on top of your right hand, criss-crossing your fingers waffle-style; hold your hands so that sunlight can beam through the gaps. You’ll see a pretty matrix of crescents on the ground. Have you ever made a turkey or a rabbit using hand-shadows? Try it during a partial eclipse; the animal’s eye will be crescent-shaped.
Partial eclipses last for more than an hour, so there’s plenty of time to play.
Meanwhile, in the middle of the South Pacific, a small number of people on cruise ships will be busy having their lives changed. The eclipse there will be total, with the moon briefly covering all of the sun. Unfortunately, the narrow path of totality does not touch land.
An almost-total eclipse can be seen not far from New Zealand (map), and in parts of Costa Rica, Panama, Columbia and Venezuela (map). In those places, the eclipse is annular. The moon is perfectly aligned with the sun, but does not completely cover it. A little bit of the sun pokes out all around, producing a “ring of fire.” Think of the shadows!
Astronomy trivia: Eclipses that are total in some places and annular in others are called hybrid eclipses. The April 8th eclipse is one of these.
The partial phase of this eclipse happens in North America between about 5:30 and 7:00 p.m. EDT (timetables). For many people, this corresponds to sunset. Crescent sunsets are pretty, but be careful. Even when the sun is hanging low and dimmed by clouds, it is still dangerous to look at. A brief glimpse through a telescope or binoculars can blind you. Try projecting an image of the sun instead (instructions).
A partial eclipse. Totally fun.
From NASA