Mark Your Calendars: North American Solar Eclipse 2017

Mark your calendars for August 21, 2017, when there will be a total eclipse of the sun traversing the middle of the United States.

Eclipses occur due to an amazing celestial coincidence—the Sun, Moon, and Earth line up to reveal the Sun’s atmosphere, it’s corona.

On August 21, 2017, millions of people across the United States will see an amazing spectacle—a total eclipse of the Sun. The Moon completely blocks the Sun, daytime becomes a deep twilight, and the Sun’s corona shimmers in the darkened sky. Image Source: Macon-Bibb County Convention & Visitors Bureau

On August 21, 2017, millions of people across the United States will see an amazing spectacle—a total eclipse of the Sun. The Moon completely blocks the Sun, daytime becomes a deep twilight, and the Sun’s corona shimmers in the darkened sky. Image Source: Macon-Bibb County Convention & Visitors Bureau

A strip of darkness about 70 miles—known as the path of totality—will cross mainland America from Oregon to South Carolina marking the first coast-to-coast crossing of the U.S. since 1918.

As totality approaches, you will see day turning to night and the Sun’s corona blazing in the sky.

The eclipse shadow makes landfall in Oregon and begins its supersonic transit across the country. This path, where the moon will completely cover the sun and the sun’s atmosphere—the corona—will stretch from Lincoln Beach, Oregon to Charleston, South Carolina. The entire transit of the shadow across the United States will take 1 hour 33 minutes 16.8 seconds.

Diagram showing the Earth-sun-moon geometry of a total solar eclipse. Not to scale: If drawn to scale, the Moon would be 30 Earth diameters away. The sun would be 400 times that distance. Image Credit: NASA

Diagram showing the Earth-sun-moon geometry of a total solar eclipse. Not to scale: If drawn to scale, the Moon would be 30 Earth diameters away. The sun would be 400 times that distance.
Image Credit: NASA

The 2017 North American Total Eclipse will transit from the Pacific Coast to the Atlantic, passing over Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, North Carolina, Georgia, and South Carolina. Anyone within this path can see a total solar eclipse—daytime becomes a deep twilight and the Sun’s corona shimmers in the darkened sky.

The point of greatest total eclipse duration is southeast of St. Louis, Missouri, and the point of greatest totality is northwest of Nashville, Tennessee.

Such is the excitement among astronomers and the American press, the event has been dubbed The Great American Eclipse.

Shaded band shows the path of totality, that is, inside the path of the Moon's shadow. Image Sourcet: Wikimedia Commons

Shaded band shows the path of totality, that is, inside the path of the Moon’s shadow. Image Source: Wikimedia Commons

Since totality will move from the Pacific to the Atlantic, nearly everyone in the U.S. can reach this total solar eclipse within a day’s drive.

The foremost criterion for selecting a site is the weather. Any location along the path of totality from Oregon to South Carolina can enjoy good weather on eclipse day, but the western half of the United States, especially from the Willamette Valley of Oregon to the Nebraska Sandhills, will enjoy the very best weather odds. The total solar eclipse will be such a spectacle that you won’t regret making the effort to find a clear viewing location.

August is a perfect time of year for camping, so consider traveling in an RV. But stay flexible if the short-term weather forecast is not favorable in your chosen location.

In this series of still from 2013, the eclipse sequence runs from right to left. The center image shows totality; on either side are the 2nd contact (right) and 3rd contact (left diamond rings that mark the beginning and end of totality respectively). Image Credit: Rick Fienberg, TravelQuest International and Wilderness Travel

In this series of still from 2013, the eclipse sequence runs from right to left. The center image shows totality; on either side are the 2nd contact (right) and 3rd contact (left diamond rings that mark the beginning and end of totality respectively). Image Credit: Rick Fienberg, TravelQuest International and Wilderness Travel

In a follow-up article we’ll detail ten locations for perfect viewing spots to view the total solar eclipse, weather permitting.

In the surrounding areas outside this path of totality, which include the remaining part of mainland United States and Canada, observers will see a partial solar eclipse where the moon covers part of the sun’s disk.

NASA's Solar Dynamics Observatory (SDO) captured a solar eclipse. Image Credit: NASA

NASA’s Solar Dynamics Observatory (SDO) captured a solar eclipse. Image Credit: NASA

As great it would be to be in the eclipse sweet spot, it’s less exciting for those in Canada. In Edmonton, Alberta, for instance, the maximum coverage of the sun by the moon when it passes over the city will be 70 per cent, about the same as Houston, Texas. Observers in Vancouver, British Columbia will see approximately 85 percent of the sun’s disk covered, about the same as Tulsa, Oklahoma. Detectable dimming in daylight hours starts to happen at around 90 per cent coverage.

The chances are, if you don’t know it’s happening, you probably won’t notice anything,

The good news is that if you can hang around for 27 years however, Edmonton will get the chance to witness a total solar eclipse on Aug. 22, 2044.

Check with local science museums, schools, and astronomy clubs for eclipse glasses—or purchase an ISO 12312-2 compliant and CE certified pair of these special shades. Image Credit: NASA

Check with local science museums, schools, and astronomy clubs for eclipse glasses—or purchase an ISO 12312-2 compliant and CE certified pair of these special shades. Image Credit: NASA

Do NOT view a solar eclipse with unprotected eyes. Permanent damage to your vision may occur. Special certified eclipse viewing glasses are needed to protect your vision. The protection afforded by regular sunglasses is insufficient.

Only during the few moments of totality is it OK to view the eclipse with the naked eye—when the sun is completely blocked by the moon. Even when 99 percent of the sun is blocked, you can still suffer burns to your retinas. DO NOT view the eclipse with the naked eye, or through an unfiltered lens.

Worth Pondering…

The moon shuts off the beams of the sun as it passes across it, and darkens so much of the earth as the breadth of the blue-eyed moon amounts to.

—Empedocles (Greek, 493-433 BC) Fragment (ca. 450 BC)

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