The Boy Scout motto is “Be Prepared.” You’ll be best served if you take heed on August 21st.
On Monday, August 21, millions in the U.S. will have their eyes to the sky as they witness a total solar eclipse. It will be hard to eclipse this eclipse.
The moon’s shadow will race across the United States, from Oregon to South Carolina. The path of the shadow, also known as the path of totality, is where those watching this spectacular occurrence will see the moon completely cover the sun. For those outside the path of totality in many parts of the U.S., including the Roanoke area, it’s still an event of a lifetime.
With that being said, here’s a number of interesting facts regarding the eclipse to get you ready, plus some tips to hopefully have you best prepared to enjoy the moment. If you’re one of the fortunate ones that plan to experience totality, you’ll remember it for the rest of your life as one of the greatest and amazing things you ever saw.
Eclipse Fests, Solar Fests, Moonshadow Fests and Star Parties are planned along the path of totality. Vineyards, museums, parks universities, breweries and just about everyone is getting into the act.
“It’s going to be hard to beat, frankly,” says Thomas Zurbuchen, head of NASA’s science mission office.
“It is the most weird, creepy, awe-inspiring astronomical event you will experience,” NASA’s meteor guru, Bill Cooke, adds.
This will be the first total solar eclipse in the continental U.S. in 38 years. The last one occurred February 26, 1979, and unfortunately, not many people saw it because it passed over just five states in the Northwest and the weather did not cooperate. Although there will be another in 2024 that crosses the U.S. from Texas up to Canada, the next time Roanoke comes close to a bull’s eye shot won’t occur until September 14, 2099.
A solar eclipse is a lineup of the Sun, Moon and Earth. The Moon, directly between the Sun and Earth, casts a shadow on our planet, also known as occultation. If you’re in the dark part of that shadow, called the umbra, you’ll see a total eclipse. If you’re in the light part (the penumbra), you’ll see a partial eclipse where the Moon seems to take a huge bite out of the Sun. A solar eclipse only happens at New Moon phase, making the Moon appear as a black, totally circular obstruction. New Moon phase is when the Moon is barely visible in the night sky, often confused in terminology with a full Moon, where the Moon is a bright globe.
Astronomers categorize each solar eclipse in terms of magnitude and obscuration. Magnitude is the percent of the Sun’s diameter that the Moon covers during maximum eclipse. In totality areas, that will be 100%. In Roanoke, it will be about 92%. If you want to head to Myrtle Beach, you’ll get a magnificent 99% performance. Everyone in the continental U.S. will see at least a partial eclipse, the least being 48% magnitude at the northern tip of Maine.
One reason for all the hoopla in this eclipse is because of totality. The totality path is the big deal with its massive path this time. A partial eclipse is still spectacular at Roanoke’s 92% magnitude, but comparing a partial eclipse to a total eclipse is like comparing almost dying to dying. Only totality reveals the true celestial spectacle; the Moon’s total blocking appearance, the Sun’s corona and strange colors in our sky.
Don’t get distracted. In the August totality path, totality lasts a maximum of 2 minutes and 40.2 seconds. That’s near Carbondale, Illinois. But, you can still get around 2 minutes of totality south of Myrtle Beach between Pawleys Island and Charleston. The center line of totality crosses 12 states, so if you have relatives in Idaho or Kentucky, this may be the time to pay them a visit. This eclipse will be the most-viewed ever because of media attention, the highway system to get to totality, the typical weather in August and the proximity to large cities near the path. For the record, the longest possible duration of totality is 7 minutes 32 seconds. The next total eclipse coming close to that will be 6 minutes 55 seconds on June 13, 2132. Most of us will probably miss that one.
So, how does the small New Moon cover the Sun? Our daytime Sun’s diameter is roughly 400 times larger than that of the Moon. But, it also lies roughly 400 times farther away. What this means is that the Sun and the Moon both have a very similar size when viewed from Earth during certain orbits. In contrast, when the Moon and the Sun are both exactly in line, but either the Moon is further from Earth or Earth is closer to the Sun, then the apparent size of the Moon is slightly smaller than the Sun, leaving the Sun appearing as a very bright ring, or annulus, surrounding the dark disk of the Moon. That situation is called an annular solar eclipse. A total eclipse, like the one on tap this time, happens when the dark silhouette of the Moon completely covers the intense bright light of the Sun, leaving only the fainter solar corona.
Although you’ll see a quick-passing, 92% magnitude in Roanoke, it’s amazing in that the Moon will be traveling at 1,498 miles per hour.
One of the great things about the totality phase is it will look best to the naked eye. You won’t need a telescope, although binoculars will give a close-up view. During totality, it’s safe to look at the eclipse. In Roanoke, with only a 92% partial eclipse, it’s important to protect your eyes with eclipse safety glasses which are cheap and will show up for sale everywhere (in early August Wal-Mart had them for $1/pair).
Once the eclipse begins, things get eerie. Animals and plants react in strange ways, the temperature will fall 10-15 degrees and the sun may provide spectacular surprises as its fiery glow shows through the valleys and rough edges of the Moon.
One thing we can promise-this event WILL happen. Comets may or may not appear bright. Meteor showers can go pfffft and the best views are after midnight. You need telescopes to see distant planets. But, in this case this solar eclipse will occur when they say, where they say, for how long they say, and in the daytime. And, this time, unlike eclipses that are only seen at the top or bottom of the world in sparsely populated areas, we get a front row seat.
Finally, a few tips for viewing the eclipse. Find an unobstructed vantage point and get there early. In Roanoke, the Moon first begins to cross the Sun at 1:12 pm. Maximum coverage of 92% occurs at 2:40 pm and the eclipse ends at 4:01 pm, for a total duration of 2 hours, 49 minutes. Forget using point and shoot cameras or cellphones: you’re wasting your time. Even if you have an expensive camera and lens, don’t get caught up in adjusting your camera a hundred times. You’ll be best served just concentrating on watching without distractions. Visit the potty well before the event because you don’t want to be in the woods when the eclipse reaches maximum. And, keep your fingers crossed that storms and clouds take the day off. If they crash the party, we’ll be shortchanged on the excitement.
Bill Turner
