What You Need To Know About The Astronomical Event Of The Century
On Monday, August 21, 2017, American’s will witness a full solar eclipse as the New Moon comes between the Sun and the Earth. The so-called Great American Eclipse will only reach what’s known as “totality” in certain states, starting in Oregon and moving slightly diagonally east, ending in South Carolina. In the surrounding areas, which includes all of the U.S. and Canada, the eclipse will be partial. Yaquina Head Lighthouse in Newport, Oregon, will be the first location in the continental U.S. to see totality. The partial phase of the eclipse will begin there at 9:04 a.m. local time and totality will occur at 10:15 a.m. From here, the Moon’s central shadow will move inland. The maximum point of the eclipse will take place near Hopkinsville, Kentucky, at 1:20 p.m. local time. Totality will last for 2 minutes and 40 seconds. It’s been a long time since Americans have been able to experience such an event. This is the first total eclipse of the Sun visible from the contiguous United States (excluding Alaska and Hawaii) since February 26, 1979. The last time a total eclipse was visible from coast to coast was on June 8, 1918. The next total solar eclipse visible from North America won’t occur until April 8, 2024. The big time gap between the occurrences makes it seem like total solar eclipses are rare, but they actually happen about every 18 months. They just aren’t visible to any given spot on Earth very often. The most detailed map I’ve found for the path of theMonday’s event comes from GreatAmericanEclipse.com and can be viewed HERE. Time Magazine has put together an interactive guide that will show exactly how the eclipse will look from anywhere in the U.S., available HERE. Approximately 12.25 million people live inside the path of totality. It’s estimated that as many as 7.4 million people will travel into those areas on eclipse day. Below are more tips on how to watch the eclipse and some other interesting facts about the astronomical event:
What Happens: During a total solar eclipse, the skies darken suddenly and the air gets noticeably colder, dropping by about -10oF at totality, says Fred Espenak, a famed eclipse expert and retired NASA astrophysicist. He notes that it doesn’t become pitch-black outside – the sky looks more like it would in the evening, about 30 minutes before sunset. Birds and animals will often go silent.
?Shadow bands: About 1 minute before totality, moving wavy lines of alternating light and dark can be seen on the ground and along walls. These shadow bands are the result of Earth’s turbulent atmosphere refracting the last rays of sunlight.
Diamond ring: Seen about 10 to 15 seconds before and after totality, the solar corona (the outer atmosphere of the sun) becomes visible; seen together with a single jewel of light from the sun, this creates a diamond ring effect.
Baily’s beads: About 5 seconds before totality, Baily’s beads appear. They are little bead-like blobs of light at the edge of the Moon. They are created because gaps in the mountains and valleys on the Moon’s surface allow sunlight to pass through in some places but not others.
Totality and Maximum Eclipse: Once the Moon completely covers the disk of the Sun, only the Sun’s corona is visible. The corona is the outermost part of the sun’s atmosphere which is made up of a jacket of gases. The corona is usually hidden by the bright light of the sun’s surface. During a total solar eclipse, the moon blocks out the bright light of the sun and the glowing white corona can then be seen surrounding the eclipsed sun.
The Sun’s chromosphere: A lower layer of the Sun’s atmosphere, the chromosphere, gives out a reddish glow which can only be seen for a few seconds after totality sets in. The phenomena experienced before totality then begin to repeat in reverse order and the corona fades.
How To View: The safest way to view the eclipse is while wearing a pair of protective safety glasses. During totality it is safe to view it with your naked eye, but you run the risk of accidentally exposing your eyes to damaging light if you miss-time this. Looking directly at the sun without proper protection can cause serious injury and even blindness. Proper eyewear has special-purpose solar filters that are not found on even the darkest of standard sunglasses. The American Astronomical Society has a list of reputable vendors and manufacturers HERE.
Cameras And Telescopes Are Not Safe Alternatives: Similarly, do not look at the sun through a camera, a telescope, binoculars, or any other optical device while using your eclipse glasses or hand-held solar viewer — the concentrated solar rays are thought to damage the filter and enter your eye(s), causing serious injury. Seek expert advice from an astronomer before using a solar filter with a camera, a telescope, binoculars, or any other optical device. Note that solar filters must be attached to the front of any telescope, binoculars, camera lens, or other optics.
Pinhole Projectors: An alternative method for safe viewing of the partially eclipsed sun is pinhole projection. You simply pass sunlight through a small opening (for example, a hole punched in an index card) and project an image of the Sun onto a nearby surface (for example, another card, a wall, or the ground). You don’t need any special equipment either! Just cross the outstretched, slightly open fingers of one hand over the outstretched, slightly open fingers of the other. Then, with your back to the Sun, look at your hands’ shadow on the ground. The little spaces between your fingers will project a grid of small images on the ground.
Thousands Of Scientists Will Be Observing: Scientists plan to use the eclipse to help solve one of the sun’s most perplexing mysteries — namely, why the corona is millions of degrees hotter than its 10,000-degree Fahrenheit surface. Because totality only lasts about two minutes in any one location, scientists will be in position across the country to capture images and data. A citizen science effort backed by the National Science Foundation, NASA, and other organizations will photograph the corona using 60 identical telescopes stationed at regular intervals along the path of totality in an effort to produce a 90-minute movie of the Sun’s corona. Other measurements and observances will be made from various probes and satellites in space. (Sources: Space, NASA, Time, Great American Eclipse)