The Penumbra Isn't Good Enough: Preparing For The Great American Solar Eclipse

May 26, 2017

Credit University of Wyoming Department of Physics and Astronomy

With the Great American Solar Eclipse coming up in less than three months, Wyomingites should find a good viewing site now. The population of the state is expected to double in size, but according to University of Wyoming astronomy professor Mike Pierce, they'll all be crowding into what's called the umbra, the 50-mile shadow of the moon that will make a stripe from Jackson to Torrington.

Pierce said to get the full effect of the eclipse, it's not good enough to watch the moon from the areas next to the path of totality known as the penumbra. For example, viewers in Laramie would only see a partial eclipse.

“You must be on the path of totality,” said Pierce. “You'll read that the sun is 99 percent eclipsed or something like that. But that's just nothing because it will get maybe slightly darker. But other than that, you won't notice anything. To really experience the eclipse you need to be within the umbra where the path of totality is.”

Pierce said, if you don't see the eclipse from there, you won't experience the third stage of a total eclipse known as totality.

“Birds will begin to roost and chirp. Temperatures will begin to drop. Animals start acting strangely. People start acting strangely!” he said. “That will last about two and a half minute, and it's really quite spectacular. It's one of these ooh and ahh moments that young people that see it will tell their grandkids about.”

Pierce recommends obtaining solar glasses or a solar filter for your binoculars or telescope since its dangerous to look at the sun with the naked eye. The total eclipse will occur Monday, August 21st.