2017: The Year of the Great American Eclipse!

2017 is here; the year of the Great American Eclipse! On August 21, 2017, a total solar eclipse will be visible in a narrow band that crosses the contiguous United States. The Moon will block out the light of the Sun for almost 3 minutes. Dusk will fall in the middle of the day. Stars will be visible. It will be a wondrous sight.
Most people in the nation will be only a day's drive away from the path of totality. Make your plans now to see it - you won't want to miss it!
 

The Moon blocks out the light of the Sun in a total solar eclipse, leaving just prominences and the Sun's atmosphere visible. Image source: Phil Hart

What is a total solar eclipse? 

A solar eclipse occurs when the Moon covers up the Sun from our perspective here on Earth. The Sun is 400 times larger than the Moon, but by coincidence is also 400 times farther away, so the two objects appear to be the same size in our sky. This is the reason solar eclipses can occur. Every once in a while, the Moon passes directly between the Sun and the Earth, and blocks out the sunlight for a short amount of time. 

When the Moon passes directly between the Sun and Earth, people in the dark part of the shadow will see a total solar eclipse. Objects are not to scale. Image Credit: Wikipedia Commons.

If the Moon orbited the Earth in exactly the same plane that the Earth orbits the Sun, we would have a lunar eclipse and a solar eclipse every month (sort of like on Mars). The reason this does not happen is because the Moon's orbit is slightly tilted in relation to Earth's orbit. Usually the Moon passes just over, or just under, the Sun's path in our sky. 

Image Credit: SMU Physics

Total solar eclipses are more rare than lunar eclipses because the Moon's shadow on the Earth is much smaller than the Earth's shadow cast out into space (the cause of lunar eclipses). There is only a thin path on the Earth where a total solar eclipse is visible.

How can you watch the August 21, 2017 eclipse? 

The total solar eclipse is only visible in a narrow path along the United States. In Peoria, the Sun will only by 90% eclipsed. If you want to see the total eclipse, you will need to travel to the path of totality. The closest cities along the path of totality to Peoria are in Southern Illinois (about a 5 hour drive) or near St. Louis (about a 3 hour drive). 

The Shawnee National Forest and Carbondale will be good places to watch the eclipse. Image Source: GreatAmericanEclipse.com

Carbondale gets 2 minutes and 35 seconds of totality. Southern Illinois University is having a big event for the eclipse. Check out their website for information. Marion has 2 minutes and 28 seconds.

From the Peoria area, it will be a little bit of a shorter drive to totality in Missouri. 

You will have to go a bit south or east of St. Louis to get the longest duration of the eclipse. Image Source

In Missouri, good cities to observe are Festus (2 minutes and 37 seconds) and St. Genevieve (2 minutes and 40 seconds) near the centerline of the eclipse.

The large yellow band across the country is the path of totality. Everywhere else in the United States a partial solar eclipse will be visible. Image Source

You might want to plan a vacation around the eclipse, and travel to a beautiful destination to watch. If that is the case, check out this excellent interactive Google Map showing the eclipse path across the United States. You can also buy a booklet with maps of the eclipse from the museum store for about $15. 

How to safely watch a solar eclipse 

For most of the eclipse when the Moon is not fully covering the Sun, you need to wear proper eye protection to be able to see anything, and to stay safe. Eclipse glasses are a popular choice, and are very inexpensive. The Peoria Riverfront Museum's store has them for sale for $1.95. 

Rules For excitedly watching the Sun with eclipse glasses.

In Southern Illinois, the partial phase will start at 11:52:26 AM (CDT). You will see a small shadow appear on the upper right side of the Sun as the Moon begins to cover it. The Sun will be totally eclipsed from about 1:20 PM to 1:23 PM. The eclipse will end at 2:47 PM.  

You will need eclipse glasses or other solar filters to view all of the eclipse phases except totality. 

Total Solar Eclipse phases in Turkey, 2006. Photo by Stefan Seip

There are fancier solar filters and glasses available at online stores like this one. This website has a ton of great information about the eclipse, and how to observe safely. Please read it, and remember that normal sunglasses are not nearly powerful enough to safely observe the Sun.

You do not need a telescope or binoculars to observe the eclipse, but if you want to use one, make sure you have a safe filter on it, or you will ruin your scope or your eyes. 

What will you see?   

If you do not have the option to travel to totality, you will see a partial eclipse through a solar filter. In the Peoria area, it will look something like this when it is maximally eclipsed: 

  
It is worth watching the partial eclipse if you cannot travel to totality - it will still be an unusual and noteworthy sight. However, if you do have a chance to go to totality, you should. A partial eclipse is exciting, but a total solar eclipse is a rare phenomenon, one of the most awe-inspiring in nature.  

If you travel to totality, this is what you will see: 

Total Solar Eclipse in Norway, 2015. Image: Stan Honda

You can safely observe totality with a telescope without a solar filter, but only totality. If you try to watch a partially phased eclipse with a telescope without a filter, you can ruin your eyes and the 'scope. Here is what the eclipse might look like through a telescope. 

A total solar eclipse as photographed through a telescope. 2009. Image: Koen van Gorp

And this is what the shadow of the Moon looks like on the Earth during an eclipse. Incredible!

The Earth during a total solar eclipse, captured by the DSCOVR satellite. Image Source

 
How can you learn more? 

The Peoria Riverfront Museum's Dome Planetarium is your resource for all information about the 2017 total solar eclipse!

We have a brand new planetarium show about eclipses on our daily public schedule called Eclipse: The Sun Revealed. It plays at 12:30 Tuesday-Saturday, 1:15 on Sunday, and 4:15 Friday-Sunday. 


Join our total solar eclipse event on the Dome Planetarium's Facebook page! We will post updates about the eclipse as the day gets closer.

Check out the EclipseWise website for a plethora of information.    
Also visit Mr. Eclipse for information about safely and successfully photographing the event.  

Other helpful sites:
eclipse2017.org   
GreatAmericanEclipse.com

Check out Tyler Nordgren's awesome space posters.

I am super excited about this total solar eclipse. It will be the first one I have ever seen, since there hasn't been one visible across the United States since 1979. There will be another total solar eclipse within driving distance in 2024. Let us know if you have any questions, and start preparing for the 2017 Great American Eclipse soon!