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Eclipse of the Sun

A solar eclipse will happen on Monday, August 21st and our area can view a partial eclipse!

David Raker,


On Monday, August 21, 2017, all of North America will be treated to an eclipse of the sun. Anyone within the path of totality, where the moon will completely cover the sun's disk will see its tenuous outer atmosphere, the corona. Totality will stretch from Salem, Oregon to Charleston, South Carolina. Observers outside this path (like in the Lehigh Valley) will still see a partial solar eclipse where the moon covers part of the sun's disk.  A total solar eclipse occurs during the moon's new moon stage when it is aligned between the sun and the Earth.  This cosmic phenomenon occurs because the sun is 400 times larger than the moon and 400 times farther away.  When totality occurs, two shadows from the moon are cast on a narrow strip of the Earth.  The ideal place to observe the total eclipse is in the moon's darkest shadow called the umbra.  Directly outside of the umbra is the lighter shadow of the moon called the penumbra.  Observers here will see most of the sun's disk covered, but not all of it.

     For those of us in the Lehigh Valley, we will be treated to a partial solar eclipse with approximately 75% of the sun covered by the moon.  The eclipse starts in our area around 1:20 p.m., will peak at 2:43 p.m. and ends around 4 p.m. 

What NOT to do versus what to do:    

1.)     NEVER look directly at the sun without using proper government approved solar eclipse glasses.  DO NOT use multiple layers of sunglasses as a substitute for proper eye protection.  Without proper eye protection damage will occur to your eyes even though you will not feel any pain.  You can purchase eclipse glasses by searching the web.  Hopefully, stores in our area will have some available for purchase. 

2.)     NEVER look through a telescope or a pair of binoculars that do not have proper filters located on the FRONT of the device.  Filters placed in or behind the eyepiece where you are directly looking may crack due to the concentrated heat from the sun.

3.)     If you want to take pictures of the eclipse, NEVER point a camera or cellphone directly at the sun without a proper filter covering the FRONT where the lens is located (NOT behind where you are viewing the image).  For cellphones or cameras with small lenses, a pair of eclipse glasses placed in front of the lens will work.  Practice a bit before the eclipse occurs.

4.)    Another option for viewing the eclipse is to use the pinhole camera idea.  All you need are two pieces of white cardboard or large index cards.  Punch a small hole in one of the pieces.  With the sun in the back of you, project the image of it through the piece with the hole onto the other piece.  You will see an image of the sun as it is being eclipsed.  You can also use a spaghetti strainer and project the image on the ground at a white piece of poster board.  As another note of caution, put on sunscreen if you plan on being out under the sun during the entire event.   

The last eclipse visible in the continental United States was in 1979 while the next one will not occur until April 8, 2024.  So get thee outside and view one of the greatest cosmic wonders in a SAFE and enjoyable way.  Clear skies!  

David Raker is an adjucnt professor of astronomy at Northampton Community College