For some fortunate sky-watchers looking up on February 15, the black silhouette of the moon will glide across the face of the sun in a majestic partial solar eclipse.
The sky show starts in the late afternoon for viewers in the southern parts of South America, the South Pacific, and Antarctica. Depending on location, viewers (with proper eye protection) may see up to 60 percent of the sun blocked by the moon’s dark disk.
Here’s everything you need to know to safely enjoy this stunning celestial event.
What is a partial solar eclipse?
The moon crosses between Earth and the sun every month, but the three celestial bodies don’t always line up in the right way to produce eclipses. That’s because the moon’s orbit is slightly tilted with respect to Earth’s, so sometimes it moves above or below the planet’s face. (Quiz: How much do you know about solar eclipses?)
A total solar eclipse—like the one that awed sky-watchers across North America last August—occurs only when all three celestial bodies are aligned in just the right way. During a total eclipse, the moon casts its dark central shadow, called the umbra, onto a very narrow strip of Earth’s surface. This kind of eclipse happens somewhere on Earth every 18 months, on average. However, any one location may experience a repeat performance only every three centuries or so.
During a more common partial eclipse, such as the one this week, Earth only passes through the moon's outer shadow, a wider but lighter section known as the penumbra. This kind of event, which occurs two to four times a year, creates a less dramatic but still impressive sky show for a much larger audience.
Where can I see the February 15 partial eclipse?
The amount of the solar disk hidden by the moon will depend on how far an observer is inside the moon’s penumbral shadow.
For this event, the best views will be from the southernmost tip of South America, where nearly 40 percent of the sun will be covered up during the peak of the eclipse. Anyone lucky enough to be at research stations along the eastern coast of Antarctica will see nearly 60 percent coverage at peak. (Find out about solar eclipse myths from around the world.)
Less of the solar disk will go dark for viewers as you head farther north. In Rio Gallegos, Argentina, residents will see about 34 percent of the sun eaten away by the moon, while people in Buenos Aires, Argentina, will see about 17 percent of the sun covered up.
When will the partial eclipse happen?
The first bite out of the sun will become visible at 18:55 UT on February 15, when the silhouette of the moon starts moving across the sun. The eclipse will reach its deepest point at 20:51 UT, and will end by 22:47 UT. For observers across South America and Antarctica, the sun should be very low to the horizon by that time and close to setting in the local sky.
You can find out when to look and how much of this eclipse you are likely to see using online tools such as those at EclipseWise.com.
Do I need any special gear to see this eclipse?
Yes. You must never look directly at the sun with your naked eyes. Even during a partial eclipse, the sun is bright enough to cause eye damage. People who want to watch should get special eclipse glasses or telescope filters that sufficiently reduce the sun's brightness and block its damaging ultraviolet and infrared rays.
If glasses and filters are not available, a simple pinhole camera provides a safe and easy alternative to enjoy the show. Use a pencil to punch a small hole in a piece of cardboard and hold it up to the sun so that light passes through the hole.
This setup casts a crisp image of the partially eclipsed sun on the ground or on any flat surface. (See the most mesmerizing photos from the August 2017 total solar eclipse.)
Sometimes, nature creates its own pinhole cameras thanks to tiny holes in tree leaves. If you are in a wooded area, scan the ground during the eclipse to see if you can catch this dazzling display.
What if I miss this solar eclipse?
This year, we’ll get two more partial solar eclipses. An eclipse on July 13 will be visible from southern Australia, while an eclipse on August 11 will darken the sun over northern Europe and northeast Asia.
The next total solar eclipse will happen on July 2, 2019, for viewers in the South Pacific, Chile, and Argentina.
Sky-watchers will have to wait until April 8, 2024, for the next major solar eclipse visible from North America. On this day, the moon’s deep shadow will cross the continent on a diagonal path traveling from Texas to Maine.