Franklin Institute's chief astronomer on the total eclipse that has his heart

Franklin Institute chief astronomer Derrick Pitts leads an eclipse workshop on the roof of the institute.

Aside from Ben himself, no Franklin Institute scientist is more beloved or better known than chief astronomer and planetarium director Derrick Pitts. The North Philly native has been at the museum on the Parkway since 1978, long enough to watch visitors go from taking class trips there to chaperoning them. Among Pitts’ titles: NASA solar system ambassador, outreach adviser to the world’s largest telescope, and go-to guy for all manner of commentary and appearances, from Comedy Central to the Philadelphia Orchestra. He recently narrated the A Space Odyssey concert at the Mann Center for the Performing Arts to honor astronaut and fellow local Col. Guion Bluford Jr.

COMING MONDAY: Derrick Pitts, the Franklin Institute’s chief astronomer, will take your solar eclipse questions live on Philly.com’s Facebook page at 3 p.m., just after the eclipse’s peak in Philadelphia.

These days, Pitts’ big, beautiful brain is particularly obsessed with the coming total solar eclipse. On Aug. 21, for the first time since 1979, the moon will block the sun over the United States, swiping a blackout shadow from Oregon to South Carolina. Pitts tells us what’s so cool about the event, where to go to view it (including where he’ll be), and which total eclipse has his heart.

Q: Why is this eclipse a big deal?

A: Three reasons. It’s a unique astronomical event simply because of the circumstances that allow eclipses to occur on this planet. The moon is of a particular size. The sun is of a particular size. There’s a particular distance between the earth and the moon, and a particular distance between the earth and the sun that allows us to have solar eclipse.

The second piece is location. While solar eclipses can number as many as five in a year, it’s really, really rare that they happen in any particular place very often.

The last piece is if you can dim out the bright light of the sun, it gives you a chance to study the corona. The corona is a fairly large mystery. We don’t know why it’s so hot, really, or how, with all the activity that generates all that heat, the corona’s structure can be so stable.

Q: And it’s an epic experience to be part of.

A: If you’re in the 70-mile-wide path of totality, you are standing in the shadow of the moon. The sky will be dark enough to see bright planets and bright stars. The wind will change. The temperature will drop. Animals will be [preparing] to go to sleep — although that may not be the case because there will be so many people standing around screaming.

Q: Can you look right at the sun?

A: During totality — which is about two minutes — is the only time you can do that. Thirty seconds before the end of totality, you’re going to have to wear eye protection again. You must use eye protection for all the partial phases.

In this region, you can’t do that [look at the sun]. That’s because we will experience a partial solar eclipse. Eighty percent of the sun’s disc will be covered by the moon. From about 1:20 to 4 p.m., it will appear as if it’s a partly cloudy day.

People in Philadelphia really need to know: No portion of this eclipse is observable without eye protection. There’s a very particular type of viewer that’s built specifically to allow you to view the sun safely, and a number of vendors you can easily find on the web. You can’t use sunglasses at all. Sunglasses are useless.

Q: Sounds like it’s going to be a much cooler experience out of town.

A: There’s one factor about this that is very new and different. The last time there was a total solar eclipse in the U.S. was 1979. Even during the partial eclipse in December 2000, the internet and social media were not as developed as they are now. Now, no matter where you are, you can enjoy innumerable live-stream events. Many, many, many more people will be able to experience the eclipse, wherever they are. You can be in an outhouse, a beauty shop, a bar, anywhere.

Q: What can we do in person in Philly?

A: The Franklin Institute is hosting an afternoon of free activities. Between 1 and 4 p.m., on the Winter Street side of the building, we’ll have indirect viewing methods: Sun spotters, pinhole projection devices.

I’ve also been doing a lot of work with neighborhood community centers through City Skies, an effort to bring astronomy content, knowledge, and experience to inner-city neighborhoods. I’ve given workshops to train centers on how to host solar eclipse viewing. I’ve distributed 5,000 solar viewers and still have another 3,000 I’ll be distributing.

Q: Where will you be for the big event?

A: Saint Joseph, Mo., near maximum duration (two minutes and 40 seconds) and the greatest eclipse. Two other colleagues and I will be at Rosecrans [Memorial] Airport. My intent is to live-stream onto the web, to do Facebook Live. At the very least, we’ll do audio voice-over of much better video from NASA.

Q: What’s been your favorite eclipse so far?

A: My wife and I got married in 1997 and planned a cruise to observe the total solar eclipse that was taking place in Europe. There was a group of astronomers on the ship. The captain needed somebody to take the lead [on the eclipse]. I had access to the captain, the bridge, the chief navigator, and plotted out exactly where I wanted the ship to be. I had the long axis of the ship pointed at the long line of the path of eclipse so people on board could see the moon’s shadow coming across the Black Sea.

The shadow comes. We’re right inside totality. Six minutes. It was phenomenal.

Q: Any last bits of advice?

If you can get yourself to the center line, you should do it. Jump in a car. Drive 12 hours. Get yourself to South Carolina.