School Programs

Viewing the Solar Eclipse - August 21, 2017

On Monday August 21, 2017 the Moon will slide in front of the Sun creating a solar eclipse. Around Cincinnati the eclipse will occur from about 1-4pm and block about 90% of the Sun. We haven't had a significant solar eclipse in the Tri-state since 2000.  If you are around Cincinnati that day and it's sunny, we'd love to have you share safe views of the eclipse with your students and co-workers. The following guide can help.

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What is a Solar Eclipse?

A solar eclipse is a phenomenon which occurs when the moon passes between the Earth and the Sun.  Even though the moon is much smaller than the sun it is still able to cover the entire sun due to its proximity to earth.

Although solar eclipses are not uncommon, happening on average 2.4 times per year, not all of them are total solar eclipses - and of those, not all are visible in the U.S. To see a total solar eclipse you must have a new moon when the moon is in the ecliptic and be in a location where the shadow it casts passes directly over your location.

The next solar eclipse will occur on August 21, 2017. The total eclipse time - from first to last contact – will last approximately 3 hours and totality will last a little over 2 minutes. Unfortunately there will not be a total solar eclipse in Cincinnati that day – but about 90% of the Sun will be blocked.  And viewing a significant partial eclipse is still an amazing event.

For the Cincinnati area, the partial eclipse will begin around 1pm, maximum eclipse is about 2:30pm, and the partial eclipse will be over around 3:52pm.

Activities for Students

Students will no doubt be curious about a solar eclipse and there are many activities that can be done to prepare them for the event. You could build your own solar system, model solar eclipses, or make your own solar viewers.  Plan ahead!

Plan a Solar Eclipse Viewing Party

The most important part of your solar eclipse party is the safety of the attendees. Make sure to plan ahead and talk to your school’s administrators in preparation for the solar eclipse. A solar eclipse can be completely safe to view as long as there is adequate preparation. Given the rarity of solar eclipses we encourage you to invite the entire school to view the eclipse together.  

View the Eclipse Safely

In order to stay safe, it is necessary for you to have the proper equipment and to follow some basic rules. The most important rule is to:

Never look directly at the Sun without proper equipment!

Do NOT use eyepiece filters. These filters have been known to crack from the heat of the Sun and could cause eye damage if used.  Never use sunglasses (even with UV coatings), film negatives, foil, CDs,   X-rays plates, smoked glass, or mylar balloons.  If it is not made for eclipses, do not use it!

Pinhole Projector

There are several different ways of safely viewing the Sun which vary in cost and complexity the simplest being a pinhole projector. Below is a simple tutorial which you can use to make a more robust model if you like.

http://www.jpl.nasa.gov/edu/learn/project/how-to-make-a-pinhole-camera/

Eclipse Glasses and #14 Welder’s Glasses

Perhaps the cheapest method of safely observing the Sun is by looking through specially-approved eclipse glasses.  You can get them online at:

https://www.rainbowsymphonystore.com/collections/eclipse-glasses-safe-solar-viewers

Looking at the Sun through welder’s glasses that are rated to a #14 shade are also dark enough to protect your eyes from the blinding glare.

Are your Eclipse Viewers and Filters safe? Important information from the American Astronomical Society.

Sun Funnel

If you own a telescope already you could use an apparatus called a Sun Funnel. This is where you project an image from the telescope, through the eyepiece, through a funnel and on to a screen.  This allows many people to safely see the Sun at the same time, and it is inexpensive to make. http://www.astrosociety.org/tov/Build_a_Sun_Funnel2.pdf

Inexpensive Solar Filters

If you have a smaller telescope there are several inexpensive filters made from black polymer which you can place over the end of the telescope in order to cut out most of the light of the Sun before it gets to your telescope. These differ from the eyepiece filters in that the filter itself does not heat up to the point of failure.  http://www.rainbowsymphonystore.com/solar-filters.html

Black Polymer for making your own filter

If you have a larger telescope you could consider making your own filter from black polymer. There are sheets which can be purchased online and there is a link to a tutorial on how to make a lens cover using these and some cardboard  http://www.amazon.com/Solar-Filter-Telescopes-Binoculars-Cameras/dp/B00DS7S52W

Instructions on how to make own filter (for larger telescope diameters)  http://www.sfsidewalkastronomers.org/index.php?page=build-a-solar-filter-for-your-telescope

Binocular tutorial

Another method of projection uses a pair of binoculars. This is a front projection method to create an image of the Sun that is still nice, easy, and safe.  http://www.space.com/15995-safe-sun-projector-binoculars.html

MORE INFO

NASA's Eclipse 2017 page

https://eclipse2017.nasa.gov/

NASA's Eclipse Videos

https://informal.jpl.nasa.gov/museum/eclipse2017

NASA's Eclipse Across America Flyer

https://eclipse2017.nasa.gov/sites/default/files/publications/2017EclipseAcrossAmericaFlyer_508.pdf

Interactive Eclipse Map

https://eclipse2017.nasa.gov/sites/default/files/interactive_map/index.html

Sky & Telescope Magazine Eclipse info

http://www.skyandtelescope.com/observing/solar-and-lunar-eclipses-in-2017/

Astronomy Magazine Eclipse info

http://www.astronomy.com/2017eclipse

Anything else you want to know about the  2017 Eclipse

http://www.eclipse2017.org/

QUESTIONS? CONTACT US

The Cincinnati Observatory may be able to provide you with safe viewing methods for your eclipse watching party on August 21, 2017.  Contact us today: 

Dean Regas, Astronomer  dean@cincinnatiobservatory.org

Phone Number (513) 321-5186

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