Hybrid Solar Eclipse: What To Know About This Week's Rare Celestial Event

A hybrid solar eclipse will grace the skies this week. Here are some of the things you might want to know about the celestial event.

Solar eclipses are events wherein the Sun, Moon and Earth are all lined up, and the Moon ends up blocking the Sun's light, casting a shadow on the Earth. Depending on the circumstances, it may be a total, partial or annular eclipse.

On Thursday, skywatchers in certain parts of the world will witness what's called a hybrid solar eclipse.

Solar eclipse basics

Basically, a total solar eclipse is when the Moon completely blocks out the Sun and, for a brief moment, the sky darkens so much so that it would appear like it's dawn or dusk.

During a partial solar eclipse, the three celestial bodies aren't perfectly aligned and hence, the Moon only partially blocks out the light of the Sun, giving it a crescent-like appearance instead.

In an annular solar eclipse, the Sun, Moon and Earth are aligned but the Moon is far away, so it's smaller and can't completely cover the light of the Sun. This leaves a "ring of light" around the silhouette of the Moon.

Another way of putting it is that the type of eclipse depends on the part of the shadow that a location is in — the dark central portion of the shadow (umbra) causes total solar eclipses, the "lighter, outer" part of the shadow (penumbra) causes partial eclipses, while the "half-shadow" (antumbra) that starts at the end of the umbra causes an annular solar eclipse.

Rare event made even rarer

But what about a hybrid solar eclipse? This is essentially a combination of the three types of eclipses that happens when the Moon is at a precise distance away that the Earth's curvatures affect the shadow cast on the Earth. This then affects what we see here on Earth.

For some people, the Moon will be farther, so they will see an annular solar eclipse. But for some, the Moon is close enough that it creates a total solar eclipse.

With the Moon's umbra and antumbra being surrounded by the penumbra, those who are just outside of the path may also see a partial solar eclipse if weather permits. And since both the Earth and Moon are moving, the type of eclipse can shift between a total and annular as the shadow moves across the planet.

"Because Earth's surface is curved, sometimes an eclipse can shift between annular and total as the Moon's shadow moves across the globe," NASA noted.

"This means the eclipse begins as an annular eclipse in areas west of the spot that faces the Moon," explained TimeandDate. "It then turns into a total solar eclipse as the shadow approaches that spot, only to switch back again to an annular appearance as it moves away towards the east."

Even if there are several eclipses each year, hybrid eclipses are actually pretty rare. So skywatchers may not want to miss it. The last hybrid eclipse happened some 10 years ago on Nov. 3, 2013, and the next one would be years later in November 2031.

This week's celestial event

The event is expected to begin at 9:36 p.m. ET on April 19 and end by 2:59 a.m. on April 20.

It will be visible only in a few parts of the world. Exmouth in Western Australia, parts of East Timor and Papua, for instance, are among the few places that will witness a total solar eclipse, Tanya Hill, of Museums Victoria, wrote in an article on The Conversation. Other places will witness a partial solar eclipse.

In Exmouth, the partial eclipse will begin at 10:04 a.m. local time on April 20 (10:04 p.m. ET, April 19) and the full eclipse will begin at around 11:29 a.m., according to the eclipse map from TimeandDate. It will reach maximum just a minute later at 11:30 a.m.

In Darwin, Australia, 85% of the Sun will be hidden by the Moon, with the eclipse beginning at around 12:18 p.m. local time on April 20 (10:48 p.m. April 19).

A partial eclipse may also be visible in other parts. Farther from the totality, in Manila, Philippines, a partial eclipse (23% coverage) is expected to begin at 11:44 a.m. local time (2:44 p.m. ET) on April 20 and reach the maximum about an hour later at 12:54 p.m.

The transition of the eclipse from annular to total and then again to annular will occur in two areas located in the middle of the ocean, according to Space.com. So, it's will be difficult to witness the phenomenon.

Enjoy the eclipse, but safely

Skygazers should remember to protect their eyes by using special eclipse glasses as one should not look into the Sun with naked eyes.

"Never look directly at the Sun because it can cause serious and permanent eye damage," stressed Hill.

They can also use other means to view it such as a solar filter/viewer or a pinhole projection.

Those who are far away from these locations need not worry because there will be live streams of the event. TimeandDate will provide a live feed of the total solar eclipse.

This marks the beginning of the eclipse parade in Australia, said Hill, as the country will also witness eclipses in 2028, 2030, 2037 and 2038.

Skywatchers in the U.S. can also start getting excited because of some upcoming eclipses that will be visible in various states. One of them will be later in the year on Oct. 14, while another one will happen on April 8, 2024.

NASA has shared a map of the events. The path of October's annular solar eclipse runs from Oregon to Texas, while places like California, Colorado and Arizona may also witness it.