2017 Total Solar Eclipse - FAQs
What is a Total Solar Eclipse? A solar eclipse occurs when the moon passes between the sun and the Earth. The moon appears to completely cover the disk of the sun. By blocking the sun's light, the moon casts a shadow that turns day into an eerie twilight here on Earth. Eclipses occur because of the special coincidence of the moon and the sun being the same size to our eyes. The sun is 400 times wider than the moon, but it is also 400 times farther away, so they appear to be the same size in the sky.
How common are Total Solar Eclipses? There is one somewhere on Earth roughly every 18 months.
When is the Great American Total Solar Eclipse? August 21, 2017. It begins on the Oregon coast and will travel across the United States exiting the South Carolina coast. The eclipse begins around 1:15pm and ends around 4:15pm. Peak eclipse is roughly at 2:45pm.
Why is this eclipse called the Great American Eclipse? This is the first total solar eclipse that's only visible in the U.S. and no other country. It will be the first total eclipse visible only in the USA since the country was founded in 1776.
When was the last Total Solar Eclipse? The last Total Solar Eclipse in the US was February 26, 1979. The last Total Solar Eclipse in the Carolinas was March 7, 1970.
What was happening during the last Total Solar Eclipse in the Carolinas (March 7,1970)? Most popular song: Bridge over Troubled Water by Simon and Garfunkel. Popular movie – Patton. Price of gasoline: $0.36. President in office: Richard Nixon. Major current event: First Boeing 747 flies. US lowers voting age from 21 to 18.
How fast does the eclipse travel? The shadow of the moon crosses the earth at 5000mph at the Poles and 1100mph at the equator. In Myrtle Beach and Florence, the moon’s shadow will be moving at 1500mph.
Where is the best place to view the Eclipse? A partial eclipse will be visible across North America, but the path of totality (100% of the sun covered by the moon) is only about 70 miles wide that stretched from central Oregon through South Carolina.
How many people have seen a Total Solar Eclipse? Because this type of eclipse is infrequent and the path of totality very small, fewer than 1 in 1,000 people has ever seen a total eclipse of the sun.
What will I see and when during the eclipse? Information on that can be found here.
Will the traffic be bad? According to NASA, eclipse day has the potential to be one of the worst traffic days in U.S. history. 12 million people live in the path of totality and an additional 200 million can drive to it in one day. Projections suggest 500,000 to 2 million people will visit South Carolina that day.
Why is it not safe to look at the sun even when only a small part of it is visible? Looking at the sun during an eclipse is more dangerous than looking at full sun. The darkness that accompanies an eclipse can override the natural tendency to squint and avert the eyes, increasing the amount of ultraviolet radiation landing on the retina and making it more likely that you'll sustain eye damage. Your eyes can sustain damage even if only a small sliver of the sun is visible. The cornea focuses sunlight on the retina and scorches it, and because the retina has no pain receptors, you don't know the damage has been done until it's too late.
Is there anytime I can look at the eclipse without protective eyewear? Yes, only during the period of totality, when the moon is completely blocking out the sun's rays and only the corona is visible.
What’s the best way to protect my eyes? Your eyes need the protection of an effective UV-blocking filter if you want to look at an eclipse. That protection isn't provided by conventional sunglasses, nor is it provided by smoky or colored glass. You need the industrial-strength protection of No. 14 welder's goggles or, even better, eclipse glasses that are specially made for viewing eclipses. Make sure any eclipse glasses meet the ISO 12312-2 international standard.
Where can I get eclipse glasses? Lowes and Walmart carry eclipse glasses locally. To date five manufacturers have certified that their eclipse glasses and handheld solar viewers meet the ISO 12312-2 international standard for such products: Rainbow Symphony, American Paper Optics, Thousand Oaks Optical, TSE 17, and Baader Planetarium. Before you purchase, make sure they are guaranteed to arrive before August 21st!
Isn’t the safety issue about eclipse viewing a bit overblown? Absolutely not! Everyone needs to be reminded that eyes never evolved on Earth to look at the sun without suffering severe damage. We have many built-in reflexes to prevent this. Viewing an eclipse is an inherently dangerous activity that you have to do very carefully in order not to suffer eye damage.
Why do eclipses move from west to east? The Moon moves to the east in its orbit at about 2110 mph. Earth rotates to the east at 1040 mph at the equator, so the lunar shadow moves to the east at 2110mph – 1040mph = 1070 mph near the equator. Basically, the Moon's shadow moves eastward at a velocity greater than the Earth's rotational velocity at any location or time, causing it to travel west to east across the Earth's surface. If you want to verify this, watch Moonrise on successive nights and you'll see that it rises later each day as the Earth's rotation needs more time to 'catch up' with the Moon in its orbit.
What is the "path of totality?" The path, in which the moon's shadow sweeps across the Earth's surface. It will cross parts of 12 states: Oregon, Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and South Carolina.
How long is totality in a given spot? Depending on where you are in the shadow of the moon, it can last a few seconds along the edge or up to 2 minutes at 40 seconds along the centerline.
How long will it take totality to cross the United States? Totality begins at 1:15pm (EDT) on the Oregon coast and will end along the South Carolina Coast at 2:49pm (EDT) so approximately 90 minutes.
Is getting to totality really that important? YES! Even if the sun is covered by 99.9% of the moon, the slightest sliver of sunlight that remains will spoil the spectacular effects that you can only get from a total eclipse. On a scale of 1 to 10, a partial eclipse, even when up 99% of the sun is covered, is a 5. Totality – 100! When totality arrives, you will be in awe of the unspeakable beauty of the corona and the array of colors and light as you've never seen before.
What will the sky look like in totality? The sky will be as dark as it is on a clear night with a full moon. Take a moment to look at the horizon. Just outside the small band of totality, roughly 70 miles wide, the Sun is still dimly shining. Shades of oranges and red normally seen at sunset or sunrise will create a beautiful 360° glow around the horizon in the middle of the day.
What are Baily’s Beads? The moon is not perfectly smooth because of the mountain ranges and canyons that pepper it’s surface. Moments before totality, all that remains of the Sun are a few shafts of light shining through these deep. The result is a few brilliant beads of shimmering light that disappear one after another within seconds.
What is the “Diamond Ring” effect? Moments before totality, only a single bead remains and it shines like a brilliant diamond set into a pale ring created by the corona surrounding the Moon’s black silhouette.
What is the Corona? The sun’s atmosphere. Ordinarily, the sun is so bright that it is not visible from earth without special cameras or telescopes. During an eclipse, the moon hides the sun’s disk revealing the Corona. It looks like a pearly white glow of gases dancing and shimmering around the edge of the moon.
What will the weather be like? It’s too early to know that for sure, but historically, we have a chance of storms in the afternoon. Typically the sky is partly sunny inland and mostly sunny along the coast thanks to the sea breeze. Rarely do we have a completely cloudy day. Despite being just a few weeks away from the peak of hurricane season, the chance of hurricane near the coast is very small.
What if it is cloudy or raining? Obviously, this will be a big disappointment, but even if clouds cover the sun during totality, it will still get darker, the temperature will go down, and any wildlife in the area will exhibit changes in behavior.
How much will the temperature drop? In our viewing area outside totality, the temperature may drop around 5° at max eclipse around 2:45pm. For areas in totality, the temperature may drop 10°.
Does the eclipse have any effect on the tides? No. Every 28 days, the moon is in its new phase and produces spring tides (tide in which the difference between high and low tide is the greatest). Total solar eclipses only occur at the time of new moon, but do not have any impact on the tides.
Could this be the most-viewed eclipse ever? Astronomy magazine says yes, basing this proclamation on four factors: 1) The attention it is getting from the media; 2) The superb coverage of the highway system in our country; 3) The typical weather on that date; and 4) The vast number of people who will have access to it from nearby large cities.
How can I photograph the eclipse? You will need to purchase a solar filter that will reduce the brightness of the sun so that the light intensity does not destroy your camera. If you ONLY take a photo at the moment of totality, you will not need this filter, and will be rewarded by being able to photograph the faint corona, which will not be visible if you have the filter in place. Most digital cameras with telephoto lenses of 100 mm or larger will show a disk for the eclipse that will show some detail. More information on this can be found here.
Can you take a photo of the eclipse with your smartphone? Yes, but the quality may be rather poor since smartphones were never designed for sun and moon photography. The best thing to do is to cover the camera lens with a solar filter during the moments before (and after) the total eclipse when the sunlight is still blinding. Though it may be OK for a few moments, it's not wise to point your smartphone camera at the brilliant, un-eclipsed sun for an extended period of time without putting a filter over the lens. A telephoto lens system is absolutely a must-have for quality eclipse photography with a smartphone. Most of the best shots you'll see related of the eclipse will be taken with professional digital cameras on tripods, or shot through a telescope.
What are some misconceptions about eclipses? Here is a partial list of what total solar eclipses DON'T do: Emit harmful rays, affect pregnant women, poison food, predict bad events or foretell major life changes.
When is the next Total Solar Eclipse? The next Total Solar Eclipse in the US is April 8, 2024. The next two Total Solar Eclipses in South Carolina will be March 30, 2052 & May 11, 2078.
What is the difference between an Annular Solar Eclipse and a Total Solar Eclipse? The moon’s path around the earth and the earth’s path around the sun are elliptical so there are times when the sun is farther away from the earth or the moon closer to the earth. In an Annular Eclipse, the Moon appears smaller than the Sun as it passes centrally across the solar disk and a bright ring, or annulus, of sunlight remains visible during the eclipse. In a Total Solar Eclipse, the Moon appears bigger and completely covers the Sun.