Here's what to know about the partial solar eclipse visible in the Philadelphia region on April 8

A solar eclipse will darken skies across North America on Monday, April 8. 

This astronomical phenomenon occurs when the moon's orbit lines up just right, so that it blocks the sun's light, as it passes between the sun and Earth. When the moon completely blocks the face of the sun, causing the sky to look like it does at dusk or dawn, that is a total eclipse.

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The eclipse's path of totality — which refers to the area where the total eclipse can be seen — will cross the northwestern portion of Pennsylvania, touching Erie, Crawford, Warren and Mercer counties. In the Philadelphia region, a partial solar eclipse will be observable, reaching over 90% totality around 3:23 p.m.

The last significant partial solar eclipse visible in the area occurred Aug. 21, 2017, when about 80% of the sun was covered. But the region hasn't seen more than 90% coverage since Memorial Day weekend 1984, when 95% totality was reached. 

"Eclipses tie us to the past and the future," Deborah Skapik, adjunct professor of physics at Saint Joseph's University, said during an interview earlier this month. 

"They're a uniquely earthling experience, because where we are (positioned) here on Earth, the moon is 400 times closer than the sun is and it's 400 times smaller. So there's a perfect setup of triangles for us to have the moon totally overlap the sun and allow the sun's beautiful outer atmosphere to be seen. So even if you got a total eclipse, as seen from another planet, it would not look like the spectacle that it looks like from here on Earth."

Skapik, a NASA partner eclipse ambassador and a SEAL solar eclipse expert, has been studying eclipses for decades. She earned her master's of science degree in Astronomy at the University of Hawaii in 1994 and worked under astronomer Jay Pasachoff at Williams College in Massachusetts, who "chased (eclipses) around the world" with student expeditions.

Along with teaching at St. Joe's, Skapik also teaches physics and astronomy at Friends' Central School in Wynnewood. She wrote a book called "Look UP, Below! An educator's guide to the April 8, 2024 total eclipse of the Sun."

According to Skapik, the next eclipse of this magnitude won't occur in the contiguous U.S. for two decades.

"It's really important to see this eclipse because the next time anything of this duration comes through is not until 2045, and that's not for this area really," Skapik said. "Philadelphia will see a total eclipse, yay, but in 2079. I don't think I'll be around. This is the time to see this thing. It's gonna be amazing."

Here's what to know about the 2024 solar eclipse, including what to expect and how to safely view it: 

What will happen during the April 8 eclipse

In Philadelphia, the partial coverage of the sun begins at 2:08 p.m. and ends at 4:35 p.m. The best time to see the peak of the event, when the eclipse achieves 90.1% totality, will be at 3:23 p.m.

To get an idea of how it will appear for the sun to be 90% hidden by the moon — or 10% of the sun uncovered, if you favor that perspective. Skapik recommended the Totality app, which allows users to type in a city and find out exactly what the sky will look like there during the eclipse. 

"Think about right before sunset tonight, when 90% of the sun is below the horizon, so you just have a little sliver (of the sun) there," Skapik said. "Whatever the temperature is, what the animals are doing, what the sky darkness level looks like — but it's happening at 3 in the afternoon. That kind of gives you a preview (of the eclipse)."

Along with the visual aspects of eclipses, Skapik noted there are other sensory aspects that people may experience, too.

"You can feel the eclipse," she said. "Sometimes the temperature will drop suddenly. Sometimes the wind will pick up."

Skapik said that the eclipse also can be heard, because some animals — like birds, crickets and frogs — are roused by the darkness to behave as they would around sunset, whether that means coming out from hiding, heading back to their sleeping places or making noise.

"And then after the eclipse is over, they're up and moving around again, just like they didn't get any sleep and they're confused," Skapik said. "So (the animals) get really messed up.

Since the eclipse will happen around school dismissal time, Skapik predicted that children may see deer out as they are bused home.

NASA has launched an Eclipse Soundscapes project to collect audio recordings of from "citizen scientists" during eclipses to analyze how the disruptions in light and sleep patterns may affect wildlife. Skapik said she and a team of Friends Central students will be participating in the project on April 8 while they're on a field trip to Vermont to partake in eclipse outreach.

For anyone thinking of making the trip to northwestern Pennsylvania — or other locations in the path of totality — Skapik said that experience is one of a kind. The moon fully covers the sun and the stars and planets become visible in the darkness.

"The total experience; it's indescribable," Skapik said. "I asked people for a word, and they can never give me one. They're like, 'magical, inspirational, weird, fantastic, scary.' There's all these adjectives, because it's like a hole is punched in the sky and then this glowing halo comes out. It looks like the heavens are opening and the rapture is going to happen. It's super weird." 

How to safely view the eclipse

To watch the eclipse, Skapik said people simply need to be looking in the direction of the sun sits at 3 p.m. People in Philadelphia may want to step into an area where the sun is visible and not blocked by tall buildings. But viewers need to take the proper safety measures to avoid eye damage. 

"This is really important: people should not look directly at the sun ever," Skapik said.

To protect the eyes, people can wear glasses specifically designed for solar eclipses. Eclipse glasses are not regular sunglasses; they are thousands of times darker and in compliance with the ISO 12312-2 international standard, according to NASA. Some people may still have their glasses from the 2017 eclipse. They can be safely used as long as the lenses aren't scratched. If not, new glasses can be purchased online. Skapik said many libraries are giving them away through the Solar Eclipse Activities for Libraries (SEAL) network.

There are also ways to safely make one's own eclipse viewing device. For instance, Skapik said people can take a kitchen colander, or something that has tiny holes in it. Viewers can let the light from the sun fall on it, and watch the reflection of the eclipse as it's projected onto the ground through the holes.

During the eclipse, Skapik urged people to be aware and careful. People who need to drive may want to plan to be off the roads that afternoon if possible, especially around 3:20 p.m. when the animals may be acting up.

Where to watch the eclipse in Philly

Several places in Philadelphia will be hosting viewing parties, including:

• The Franklin Institute
• Glen Foerd
• Independence Visitor Center 
• Marconi Plaza
• Temple University
• The Woodlands

The Kimpton Palomar Philadelphia hotel is offering special one-day-only packages featuring a 1 p.m. check-in time, approved viewing glasses and a smartphone filter for cell phones to capture the event.

Of course, what exactly viewers see may depend on the weather and cloud coverage that day. The Accuweather forecast for April 8 predicts a high of 64 degrees with a cloud cover of 46% in the afternoon. If it ends up being too cloudy to fully enjoy the spectacle, NASA will offer telescope live feeds of the total solar eclipse. 

Whether you wear solar eclipse glasses, use a colander, click onto a live stream or celebrate at a watch party, the 2024 partial solar eclipse in Philadelphia promises to be a historic event. 

"It connects us to what our ancestors saw," Skapik said. "It connects us to what our future generations will see, the same unifying experience and the same feelings."