A Guide to Viewing the Total Solar Eclipse of 2017 Discuss this article in the forums
Overview
On August 21, 2017, a total solar eclipse will pass from west to east across the lower continental United States for the first time since 1918. More than 300 million people live within a day's drive of the narrow path of this eclipse, so it may be the most watched astronomical event in history. This guide shows you when and where to see the total solar eclipse of August 2017 and gives you some tips about how to safely see the eclipse with or without a telescope.
1. Solar Eclipse Basics
It's a remarkable coincidence, but the Sun, which has a diameter of 400 times greater than our Moon, is almost exactly 400 times farther away. That means, when the alignment is right and the Moon passes directly between the Earth and Sun, the Moon almost exactly covers the visible part of the Sun's surface for a few minutes and leaves the eerie glow of the Sun's outer corona visible to Earthly observers over a long but very narrow path across the Earth's surface. This is a total solar eclipse.
Figure 1 - A total solar eclipse occurs as the Moon completely covers the bright face of the Sun, and reveals the reddish chromosphere and white streamers from the solar corona. Credit: Luc Viatour/Wikipedia Commons).Total solar eclipses are a common event somewhere on Earth, and they occur twice a year, on average. However, a total solar eclipse is rare at any particular place on Earth. It takes many hundreds of years - on average - for such an event to revisit a particular location. Nor does the Moon's shadow necessarily cast itself in convenient locations during a total solar eclipse. These events can occur in populated areas, but are more likely to occur in oceans, arctic regions, or in the middle of a desert simply because these regions cover more of the Earth than densely populated urban regions.
During a total solar eclipse, as the Moon passes between the Sun and Earth, it casts two types of shadows. The umbra is the narrow dark shadow cast by the Moon, while the penumbra is a fainter outer shadow. During an eclipse, both shadows travel along the surface of the Earth at more than 1,000 miles per hour as the Moon moves along in its orbit, and these shadows move west-to-east across thousands of miles of the Earth's surface during the eclipse. The path of the umbra is only about 70 miles wide, roughly, and within its path an observer sees the full total solar eclipse during which the Moon blocks the bright face of the Sun. This is the path of totality. You MUST be in this path to see the total eclipse. Along the centerline of this path, you will see between two and seven minutes of totality, depending on the Earth-Moon-Sun alignment during the eclipse. Off the centerline, but still within the narrow path of the umbra, the duration of totality decreases.
Figure 2 - The geometry of a solar eclipse showing the umbra and penumbra shadows cast onto the surface of the Earth. Image credit: Wikipedia CommonsThe penumbra is much wider than the umbra and spans many thousands of miles on either side of the path of totality. Within this shadow, an observer sees a partial solar eclipse in which the Sun's face is only partially covered by the Moon. More of the Sun's face appears covered for observers closer to the path of the umbra.
Not all solar eclipses are total. If the Earth, Moon, and Sun are not perfectly aligned, but they are still aligned to within their angular diameters, the Moon does not completely cover the face of the Sun and does not cast an umbra onto the Earth but only a penumbra. Observers along the path of the penumbra will see a partial solar eclipse, but no one will see a total eclipse. And if the Moon passes directly between the Earth and Sun when it's at near its most distant point in its monthly orbit around Earth, where its apparent diameter is slightly too small to completely cover the Sun, a thin ring of the Sun's light is still visible around the Moon's dark disk. This is an annular solar eclipse.
Figure 3 - A partial solar eclipse (left) and an annular solar eclipse (right). Credit: Wikipedia CommonsA total solar eclipse is by far the most spectacular of the three types, and the eclipse of August 21, 2017 will be of this type. Figure 2 shows the outline of the narrow path of the umbra and much wider path of the penumbra of this event.
2. The Total Solar Eclipse of August 21, 2017
Scientifically, the total solar eclipse of August 21, 2017 is not expected to be more important than any other total solar eclipse. But it will be the first coast-to-coast total solar eclipse across the continental United States in more than 99 years. There has been no total solar eclipse visible at all over the continental United States since February 26, 1979, when the path of the Moon's shadow traveled across Washington state, Idaho, Montana, and part of North Dakota before moving northeastward into Manitoba, Ontario, and Quebec in Canada. The last 'coast-to-coast' eclipse in the U.S. happened on June 8, 1918 when the Moon's shadow moved from Oregon to Florida. Because of its location in a populous country, where more than 300 million people live within a day's drive of the path of totality, this will be perhaps the most watched astronomical event in history. The 'Great American Eclipse', as some call it, will give many skywatchers their best chance at seeing one of the most awesome spectacles in nature without the need to travel to a remote international location.
Figure 4 - A map showing the narrow path of the umbra (in dark blue), where the total solar eclipse is visible, and the very wide path of the penumbra (in the grid of green and cyan), where a partial solar eclipse is visible to some degree during the eclipse of August 21, 2017. Image credit: NASA.3. When and Where to see the August 2017 Total Solar Eclipse
The 'Great American Eclipse' begins as the Moon's shadow falls on the north Pacific Ocean at 16:48:39 UT (Universal Time) or 09:48:39 Pacific Daylight Time (PDT) on the morning of August 21, 2017. The shadow makes landfall at 17:10:58 UT or 10:15:58 PDT on the Oregon coast, then speeds southeast over the continental United States for the next 93 minutes before moving over the coast of South Carolina into the Atlantic Ocean at 18:49:01 UT or 14:49:01 Eastern Daylight Time. The total eclipse continues into the Atlantic Ocean towards, but not reaching, Africa and ends at 20:01:35 UT, a little over three hours after it began.
The path of totality of the eclipse will pass through Oregon, Idaho, a tiny edge of southwestern Montana, Wyoming, Nebraska, extreme northeastern Kansas, a tiny piece of southwestern Iowa, Missouri, southern Illinois, Kentucky, Tennessee, northeastern Georgia, North Carolina, and South Carolina. The penumbra, where a partial solar eclipse will occur, passes across the rest of the United States, all of Canada, Mexico, and Central America, and northern South America.
The total eclipse will also pass over cities and large towns including Salem, OR, Idaho Falls, ID, Casper, WY, North Platte and Lincoln, NE, Kansas City, MO (barely), southern St. Louis, MO, Nashville, TN, and Greenville and Charleston, SC. Along the center of the path of totality, the total solar eclipse will appear to last about two and a half minutes. The eclipse will last longest, about two minutes and forty seconds, near Carbondale, IL.
This link from Eclipse2017.org gives a table of the duration of the total eclipse in hundreds of towns across the country.
And this video from GreatAmericanEclipse.com shows a short video of the path of totality across the United States.
If you plan on traveling by car to see the 2017 total solar eclipse, you may find it useful to pack eclipse expert Fred Espenak's Road Atlas of the eclipse. This detailed map shows the highways and back roads along the path of the eclipse from coast to coast.
Figure 5 - The Road Atlas for the Total Eclipse of 2017Fred also has a detailed guide to the facts and viewing locations for the August 2017 eclipse in his Eclipse Bulletin.
4. The Weather Prospects for the Eclipse
Astronomers can calculate the timing and position of a solar eclipse down to the second and the yard, but calculating the weather at any particular position is a much more challenging proposition. It's frustrating to travel for hundreds of miles (or more) to see a solar eclipse only to get clouded out. Even on a mostly sunny day, a patch of cumulus clouds can float across the Sun at just the wrong time. But predictions based on historical weather patterns during the day in late August in each state suggest some locations offer a better chance of clear weather than others. Figure 6 below shows the statistical chances of morning and afternoon clouds along the path of totality from coast to coast.
While the place of first landfall of the eclipse, on the coast of Oregon, is a geographically beautiful location, the chances of mid-morning fog are quite high. At the other end of the country, in North and South Carolina and Kentucky and Tennessee, the chances of afternoon clouds are also greater than 70%. It's also hurricane season on the east coast and it tends to be quite humid. It may be a beautiful day when the eclipse happens in these locations, but the odds are against it.
Figure 6 - Morning and afternoon weather prospects for the total solar eclipse of 2017 along the path of totality. Credit: Jay Anderson at Eclipsophile.comMost experienced eclipse watchers are planning on setting up in eastern Oregon in or near the little town of Madras. It sits at the intersection of four highways, so you can move around to find the best sky if necessary. The cities of Salem and Portland have extensive lodging options and are just a few hours away. Salem itself sits in the path of totality, so it will be a busy place. Viewers in Portland will only see a partial eclipse. Madras is just east of the lovely stratovolcano Mt. Jefferson, so observers will see the peak of the mountain darken 17 seconds before the Moon's shadow descends on the town at a speed of more than 2,000 mph. The eclipse begins in the U.S. on the west coast of Oregon at 10:16 PDT, then moves into Idaho at 10:27 PDT.
Some eclipse watchers and photographers looking for beautiful foregrounds in which to capture the eclipse will try Idaho where weather prospects are good. In the eastern part of the state, Rexburg is a promising location. It's just north of Idaho Falls and offers good roads for mobility in case of last minute clouds. In the western part of the state, Highway 95 between Weiser (on the Snake River) and the Marin Creek Reservoir offers good odds for clear skies and totality durations of just over 2 minutes. Nearly smack on the centerline of the eclipse, Casper will likely be a popular place for eclipse watchers. Hardier souls and photographers may head to Grand Teton National Park in the western end of the state.
For observers near the center of the country, Nebraska is a good prospect to consider. The path of the eclipse runs from the northwestern to southeastern tips of the state from 1:46 p.m. MDT to 2:09 p.m. MDT. Highway I-80 from North Platte to Lincoln will serve as a main artery for eclipse chasers who can use the good road network here to move towards better weather. On the I-80 just south of Grand Island, the eclipse lasts 2 minutes and 30 seconds.
Moving east from Nebraska into Missouri, Illinois, Kentucky, and so forth the chances for cloud cover increase, but many towns in these states-including Nashville-will organize events around the eclipse. Expect crowds in the larger cities and towns, and hotel rooms will be sold out months in advance. The Great Smoky Mountains National Park in North Carolina and Tennessee is a spectacular location to observe an eclipse, especially at high points such as Clingmans Dome where it may be possible to see the Moon's shadow moving across the surrounding landscape at nearly a thousand miles an hour. Again, large crowds and the weather are the weak points here, and it may be difficult to maneuver out of the park at the last minute if the weather turns cloudy.
Wherever you go, if you can, stay mobile so you can evade cloud cover and get to someplace better on the day of the eclipse. Locations with access to highways offer that option. Trying to observe the eclipse from rural areas or parks may make it harder to get on the move at the last minute. Since the eclipse occurs in summer, you may want to travel in an RV or pack a tent and sleeping bag in case you need to travel hundreds of miles from your home or hotel room and can't make it back after the eclipse.
5. Finding a Place or Event to See the 2017 Eclipse
Once you're in the path of totality and the weather looks promising, you need to find a place to sit or stand and enjoy the spectacle. There are tens of thousands of miles of open road from Oregon to South Carolina within the path of totality where you can pull over and see the event. Anyone can pull over off the road onto land that is governed by the U.S. Bureau of Land Management. There are also hundreds of towns each with areas or parking lots that can allow for great views. There will also be events organized in observing fields such as farms, parks, airports, and even stadiums. The website Eclipse2017.org is a great resource to find a location with an organized event.
6. How to Safely Observe a Total Solar Eclipse
The dangers of watching a total solar eclipse are real, but they are often overstated in the media. This section will sort out the facts and show you how to safely watch the eclipse of 2017 before, during, and after totality.
A total solar eclipse has five stages. In only one stage - the brief stage of totality when the Moon completely covers the brightest part of the Sun for a few minutes - is it safe to observe the Sun without a safe solar filter over your eyes or over the objective lenses of a camera, telescope, or binoculars. Aside from the brief few minutes of totality, you MUST use a safe solar filter to observe the eclipse.
In the first phase of the eclipse, called first contact, the leading limb of the Moon becomes visible across the Sun's disk. It looks like the Sun has a bite or a notch taken out of it. The Moon continues to cover more of the Sun, and once 70% or more of the Sun is covered, you may notice a slight change in the lighting of the surrounding landscape. But the Sun is still far too bright to look towards without a safe solar filter.
Finally the Moon will almost completely cover the Sun. Just a few rays of light will shine through valleys or gaps between mountains on the limb of the Moon. This will appear a string of bright points along the Moon's edge that are called 'Baily's Beads'. At last, a single point of light will remain giving rise to the 'Diamond Ring' effect. Even at this point, the few sunrays peeking through are still too bright to take in without a filter. At the second phase of the eclipse, called second contact as the trailing limb of the Moon covers the Sun, the last bead of light will slowly grow fainter as the Moon completely covers the Sun like a lens cap. The sky and surrounding landscape will grow dark, birds and animals will grow quiet, and the air will cool noticeably. This is the beginning of totality, and as this point you can remove the solar filters from your eyes or telescope to see the awesome spectacle of the red chromosphere and icy white corona surrounding the black Moon.
The video below shows you an extraordinary close-up of a solar eclipse in 2017. Note the Diamond Ring effect at the beginning of the total eclipse at third contact, and the reemergence of the Diamond Ring along with Baily's Beads at the end.
When the Moon maximally covers the solar disk, we reach the instant of maximum eclipse. Then the Moon moves further so that the trailing limb exposes the Sun and the Diamond Ring and Baily's Beads reappear. This is third contact and the point at which the total eclipse ends. You must look away from the spectacle at this point, however beautiful you may find it. Put on your solar eclipse glasses or solar filter and continue watching the partial phase of the eclipse over the next 90 minutes or so. Finally, the Moon's trailing edge will pass across the Sun-this is fourth contact-and the Sun's disk will appear whole again.
The span of time from second contact to third contact- the total eclipse- lasts at most two minutes and forty seconds, or more typically two minutes and twenty or thirty seconds depending on the location near the centerline of the path of totality. If you are off the centerline of the path of totality, it will last for a shorter time. If you are outside the path of totality, you will only see a partial eclipse of the Sun and you will need eye protection for the entire event.
7. Solar Filters for Safely Observing a Solar Eclipse Without a Telescope
While a safe solar filter is essential for observing the 2017 solar eclipse, such filters for naked-eye observation are quite inexpensive. A simple pair of eclipse glasses or a solar viewing card costs a few dollars and can provide excellent views of the Moon passing across the Sun's disk without a telescope. These simple filters use a special plastic solar film to reduce the Sun's intensity by a factor of 100,000 or more to a safe level. They pass so little light that you can't see anything else through them other than the bright disk of the Sun. So to see the brief phase of totality, when the Moon completely covers the Sun as described in the previous section, you will need to remove these glasses to see the action. When you see the Sun poke out in the form of Baily's Beads or the Diamond Ring, look away from the Sun and put them back on before you look at the eclipse again.
Figure 7 - A pair of solar eclipse viewing glasses (left) and a solar viewing card (right).If you want a slightly larger image of the Sun before or after totality, Celestron offers a 2x Power Viewer solar eclipse viewer that offers a 2x magnified but still completely safe look at the partially-eclipsed Sun
Celestron also offers 2-piece, 3-piece and 8-piece eclipse observing kits that include solar glasses, eclipse books and guides, and solar observing cards.
Before using a pair of eclipse glasses or a solar viewer, make sure they are in good condition. Hold them up to a lightbulb or to the sky away from the Sun and look for tiny pinholes or tears in the plastic filter. If you can see any light, discard them and grab a new pair.
A good sheet of #14 welder's glass offers an alternative to eclipse glasses or cards. If you have access to a welding supply store, see if you can get a small piece of glass, at least a few inches on a side. Don't use #12 glass... it will pass too much sunlight to be safe.
NOTE: Solar eclipse glasses and viewers and welder's glass are for use in viewing the Sun with your otherwise unaided eyes only. Do NOT use these devices to view the Sun through an otherwise unfiltered telescope or binoculars. The concentrated image of the Sun can quickly damage and burn through solar film and glass and result in permanent eye damage.Solar film and welding glass reduce the brilliant visible light from the Sun's disk. They also reduce dangerous ultraviolet (UV) and infrared (IR) light and heat from the Sun. However, you may hear of other options that will filter the Sun's light, options such as plastic CDs or DVDs, photographic film, dark sunglasses, metallic candy wrappers or thermal blankets, or the bottom of dark beer bottles. None of these are safe. Even if they reduce the visible light sufficiently, they will not block UV and IR light to a safe level. Do not use them!
Figure 8 - A simple pinhole 'camera' to observe the partial phase of a solar eclipse. Credit: Wikipedia Commons.Any even simpler method to view the progress of a solar eclipse involves the construction of a pinhole camera. Get a piece of cardboard or thick paper, poke a small hole through it, hold it up to the Sun and look for the small projected image of the Sun on the ground, a wall, or a piece of paper. The farther the image is cast, the larger it will look. Don't look at the Sun through the pinhole.
8. Solar Filters for Safely Observing a Solar Eclipse With Binoculars or a Telescope
With their greater resolution and magnification, a telescope or a pair of binoculars reveals much more detail during the partial and total phases of a solar eclipse. But it's even more essential to equip these instruments with proper solar filters during the partial phases of the eclipse. You MUST NOT use solar eclipse glasses or welder's glass to observe the Sun through an otherwise unfiltered telescope. The concentrated light from the objective lens will quickly damage these filters and pass intense and highly dangerous sunlight into your eye.
You get the best and safest views of the Sun using a solar filter mounted over the objective lens or mirror of a telescope or both objective lenses of binoculars. A solar filter reduces the brilliant light and heat from the Sun before it enters the telescope and allows you to get safe, high-magnification views of the Sun's disk using the same eyepieces and accessories you use for observing objects in the night sky.
There are two main types of solar filter: broadband or white-light filters and narrowband filters such as H-alpha. Broadband or white-light filters are the simplest and least expensive type of solar filter. They are made from reflective glass or sheets of Mylar or a more specialized optical film and mounted in a cell that fits over the objective of a telescope. These filters reduce the intensity of the Sun's heat and light by a factor of 100,000 or more. Once the solar filter is mounted on the telescope, just select a standard astronomical eyepiece to get the best magnification to frame the Sun in your telescope's field of view.
For casual observation of a solar eclipse with a telescope, filters made from Baader AstroSolar film are a good choice. They come mounted in a cell and are made to fit over the objectives of telescopes of a wide range of apertures. They sometimes also come in pairs to fit over the two objective lenses of a pair of binoculars. The costs range from $40-$200, approximately, depending on their size and configuration. There are other alternatives for white-light filters, and you can learn more about these optical tools at this link.
Figure 9 - A white light solar filter reduces the Sun's visible light, infrared light, and heat to a safe intensity before it enters the telescope.During the brief phase of totality, you can remove the solar filter from the objective of the telescope and examine in more detail the delicate streamers of the Sun's corona and the ruby-red rim of the chromosphere. But when the Diamond Ring shows itself towards the end of totality, look away fast. Replace the solar filter over the telescope's objective before you look again.
While you can get a pair of white light filters for many standard binoculars, an even more convenient alternative for solar observing during or after an eclipse is a pair of dedicated solar binoculars. These tools offer a great deal of convenience because the white-light solar filters are built in to the optics so you don't have to worry about remembering to mount the filters over the objectives. Lunt makes an 8x32 SUNocular in a variety of colors, and Celestron offers their 10x25 and 10x42 EclipSMART solar binocular, both of which are good options for general solar observation and for observing the partial phase of a solar eclipse.
The most striking views and images of the Sun are obtained with H-alpha and other narrowband solar filters. An H-alpha filter, the most commonly used narrowband filter by amateur astronomers, gives a view of glowing hydrogen atoms in the chromosphere, a region of the Sun's atmosphere above the much brighter photosphere. These filters enable views of solar features that are not visible with broadband solar filters including solar prominences and filaments, which are large arcs of hydrogen gas suspended in magnetic fields above the limb of the Sun, bright plages above sunspots, and Ellerman bombs, fleeting events associated with solar magnetic fields breaking through into the photosphere and chromosphere.
H-alpha filters or dedicated telescopes that incorporate them, are much more expensive than white-light filters. If you have the budget, they are also excellent choices for observing the progress of a solar eclipse towards totality and they give some striking visual views and images. However, H-alpha filters come with extra components that are difficult to remove from a telescope quickly during the brief span of totality during an eclipse. And dedicated H-alpha telescopes cannot be used without a filter to observe totality because they won't pass enough light. So H-alpha scopes are an excellent complement to naked-eye observation or a second telescope or binoculars with a white-light filter.
9. How Can I Take a Photograph of the Total Solar Eclipse?
When it comes to trying to take an image during the brief few minutes of totality, many expert photographers and amateur astronomers have one suggestion: don't. You only have, at most, 150-160 seconds during the August 2017 eclipse to enjoy one of the most spectacular events you will ever see. You don't want to spend time fiddling with your camera during this fleeting opportunity. This will surely be the most photographed eclipse of all time, so if it's your first total eclipse, just enjoy the show and you can see plenty of images taken by expert photographers afterwards.
If you wish to try your hand at imaging, here are a few tips and ideas to get you started. You can also learn more about imaging the Sun before, during, and after and eclipse with a camera and telescope at this link [Coming soon].
Figure 10 - A cropped image of the a total solar eclipse taken with a DSLR with a 55mm focal-length lens, ISO1600, f/4, and 1/15s shutter speed. Image credit: Romeo Durscher/NASA GoddardHere are ten tips to help you try to snap an image during a total solar eclipse:
- Taking an image of a solar eclipse during the partial phase involves the same consideration as imaging the Sun in general. You MUST use a solar filter over your camera lens or the objective lens of your telescope or binoculars. If the Sun is too bright to look at with your eyes without a solar filter, it's too bright to image without a solar filter.
- As with visual observation, once the eclipse reaches totality and become safe enough to see with your eyes, you must remove the solar filter from your camera. Otherwise, your camera will not see anything. Once totality ends, if you wish to image the subsequent partial eclipse, you must replace the filter.
- During totality, the Sun's corona appears about as bright at the full Moon. So you can set your camera accordingly for shutter speed, aperture, and ISO. Try ISO 200-400, aperture of f/4 to f/5.6, and a shutter speed from 1/10s to 1/1000s over multiple images.
- To get a close-up of the Sun with a camera, you will need a lens with a focal length of at least 300mm (35mm equivalent). Otherwise, the image of the eclipsed Sun will be quite small. The Sun and Moon only appear as large as half the width of your little finger held at arm's length.
- If you don't have a long-focal length lens or telescope, and if you just have a point-and-shoot camera or a smartphone, then consider snapping an image of the surrounding landscape during the total eclipse, or of people silhouetted against the darkened sky.
- Do not use a flash. It will not help with an image of the eclipse and it's distracting to those around you.
- Don't trust autofocus to work correctly during totality. Focus on the Sun manually through a solar filter, then turn off autofocus before totality begins.
- Practice focusing and taking images during the partial phase of the eclipse before totality begins, or practice weeks in advance on the full Moon.
- Make a checklist of all the equipment you need for the eclipse, especially if you are traveling. Also make a checklist of the steps required to take an image of the eclipse, including these tips.
- Use a tripod if you can to get a steadier image. And use a timed or remote shutter release to avoid camera shake.
Figure 11 - The image of a partially eclipsed Sun through a solar viewing card held at arm's length. Image credit: Tom Ruen/Wikipedia Commons10. Additional Resources - Books and Websites
For more detailed information related to understanding and viewing the August 21, 2017 total solar eclipse, you can refer to the following books, maps, and guides:
Eclipse Bulletin Total Solar Eclipse of 2017 August 21 by Fred Espenak
Road Atlas of the Total Solar Eclipse of 2017 by Fred Espenak
Your Guide to the 2017 Total Solar Eclipse by Michael Bakich
Over 1,000 Places to see the Total Solar Eclipse August 21, 2017 by Craig Shields
The following websites also have excellent information related to the eclipse:
Great American Eclipse Website
Eclipse 2017.org
NASA's Main 2017 Eclipse Website
Additional Resources - Basic Eclipse Viewing Tools
Safe and approved solar eclipse glasses by Thousand Oaks
Solar viewing card by Thousand Oaks
SUNocular Solar Binoculars by Lunt
Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.
A Guide to Viewing the Total Solar Eclipse of 2017
Please login or register to watch, comment, or like this article.
Please login or register to watch, comment, or like this article.
Orion25 likes this.
Rate This Article:
