Do you have it yet? The fever? There can be a total eclipse of the sun somewhere in the world about once every 18 months, but this is the first time we have had a total eclipse cross the US from Pacific to Atlantic since 1918. Colorado Springs was just outside the path of totality for that one, but was a major player in the 1878 eclipse with scientists travelling here from back east to observe from the Pikes Peak observatory. Scientists relied on eclipses to be able to observe the sun’s atmosphere; and Colorado Springs was anxious to make its mark in the scientific community, which was dominated by easterners. The next total eclipse over the Springs will be in 2045, but if you’re willing to head east you can catch one in the Midwest in 2024.
In Colorado Springs the August 21 eclipse will be at 11:47 am, and will be about 90% complete. We have to go to Wyoming or Nebraska to catch a total eclipse (Click for an interactive map). So what’s all the fuss? 90% sounds pretty darn good and you can see that from your own back yard. But if you catch the fever, that may not be good enough. Those two minutes of being in the moon shadow are supposedly quite special. So much so that the experts say don’t even think of trying to photograph it. Just be there and watch.
As the moon begins to pass in front of the sun, taking a bite out of it, as many ancient myths recount, the sky will get progressively dusky, but this may not even be noticeable if you’re not paying attention. It is important to only look at the sun through special eclipse glasses. Or project its image onto the ground or a piece of paper with a pinhole. The small spots of light shining through tree leaves will show miniature eclipses on the ground. You can make a wonderful projection through a kitchen colander.
About a minute before totality there may be shadow bands, moving wavy lines of light and dark on the ground. These are the result of the last rays of light refracting through earth’s atmosphere. The totality of this eclipse will last about two minutes. As the moon shadow sweeps over and the moon covers the sun, the sky will get dark, the stars and planets will be visible, with just a rim of “sunset” all around our horizon. And it may get cold. I’m told, don’t run for a sweater, just wait it out and experience the power of the sun returning, bringing its light and heat back to the earth.
While the moon covers the sun you do not need special glasses to look at it. With the intensity of the sun hidden, you can see the corona, the charged particles of the sun’s atmosphere. Streaks in it are the magnetic fields carrying plasma out into space (and creating the solar wind). The chromosphere is a lower level of the sun’s atmosphere, which appears for a few seconds as a red glow right around the moon. During the “diamond ring” phase, at the beginning and end of totality, just a spot of intense light is visible. Sometimes there are more than one bead, “Bailey’s beads”, which is the sun shining between the mountains of the moon. One of the great unsolved problems in physics is why the temperature of the corona is millions of Kelvins higher than the sun’s surface.
Because planets’ and moons’ orbits are elliptical rather than round, eclipses vary depending on how close the moon is to the earth. When the moon is farther away, there is more of a bright ring around the moon, called an annular eclipse. Interestingly, the moon is slowly getting farther away from the earth. In the age of the dinosaurs it was closer, and eclipses lasted longer and covered more of the sun. It is really just a fluke of our timing in the universe that the moon fits pretty perfectly over the sun for us. The sun’s diameter is 400 times that of the moon but 93 million miles away. Both orbs appear the same size to us here on earth.
There is a wealth of information online about the eclipse. Here are a couple great websites:
NASA eclipse website: https://eclipse2017.nasa.gov/eclipse-101
Great American Eclipse: https://www.greatamericaneclipse.com/
So get yourself a pair of eclipse glasses and catch the fever.