The Great 2017 Solar Eclipse

Aug 09, 2017

On Monday, 21 Aug 2017, a total solar eclipse will cross the USA northwest to southeast from Oregon to South Carolina.  A public presentation in preparation for the eclipse will be held at UW Space Place on Friday, 08/18 at 8:00pm.

It has been nearly a century since a total solar eclipse crossed the country so extensively.  The path within which the eclipse will appear total is only about 70 miles wide.  See this interactive map of the eclipse path.  Outside of that relatively narrow path, the rest of North America will see a partial solar eclipse.  In a total eclipse, the disk of the moon completely blocks the disk of the sun for few minutes, dramatically turning day into night and back.  The entire eclipse, including partial and total phases, takes nearly three hours.  (Specific times vary with location.  Again see the interactive map.)  Before and after totality, viewers see the sun only partially obscured, and during that time one must use special methods, such as eclipse viewers or pinhole projection. In fact, it is easy to make a pinhole projector.

Outside the path of totality, viewers in North America, including Wisconsin, will see only the partial eclipse.  In the table below are beginning, middle, and end times for selected locations in Wisconsin. Again, from Madison, it will not be safe to look directly at the Sun during the ecplise without special protective equipment.

Solar Eclipse, 21 August 2017. Wisconsin locations. Times are CDT.
Location Start Mid-Eclipse End Maximum
obscuration %
Platteville 11:48:44 13:13:40 14:37:02 87.4 2:48:18
Kenosha 11:53:53 13:18:44 14:41:09 84.6 2:47:16
Madison 11:50:47 13:15:19 14:38:00 85 2:47:13
LaCrosse 11:47:23 13:11:16 14:33:59 84.6 2:46:36
Milwaukee 11:53:42 13:18:07 14:40:12 83.3 2:46:30
Oshkosh 11:52:26 13:15:55 14:37:26 80.8 2:45:00
Eau Claire 11:47:03 13:09:58 14:31:56 81.8 2:44:53
Stevens Point 11:50:33 13:13:40 14:35:13 80.6 2:44:40
Green Bay 11:53:28 13:16:23 14:37:18 78.8 2:43:50
Eagle River 11:51:23 13:12:58 14:33:04 75.8 2:41:41
Superior 11:46:35 13:07:30 14:27:51 76.3 2:41:16
Ashland 11:48:39 13:09:38 14:29:41 75.4 2:41:02

A solar eclipse requires very little preparation or special equipment. Even nature creates pinhole images in the sunlight shining through leaves of trees onto the ground.  No telescope or other optical equipment is needed for the casual eclipse viewer. In all of Wisconsin, the middle and deepest part of the eclipse occurs around 1:15pm CDT on the 21st.  That would probably be the most interesting time to plan a look at the eclipse.

Eclipse viewers are in high demand, and many astronomical facilities, including UW Space Place, are sold out.  However, solar viewers might still be available at some major discount retailers.

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