Just under seven years ago, a total solar eclipse crossed over southern Illinois. Now, on Monday, April 8, 2024, another total solar eclipse will pass over southern Illinois. Unlike the 2017 eclipse that moved northwest to southeast, the 2024 eclipse will move from southwest to northeast, bringing the path of totality closer to northern Illinois. Here’s how to safely watch the total eclipse.

Total solar eclipses, when the moon completely blocks the sun, are not that uncommon, happening every year or two. However, because the shadow of the Moon on the Earth is relatively small, the path of totality is only visible to a narrow band, and with about 75% of the Earth’s surface covered with water, that band is often over the ocean. The 2024 eclipse is a rare opportunity to experience totality (when the shadow of the Moon is over you). The next total eclipse in the lower 48 states will be in 2044 over Montana and North Dakota. The next one visible in Illinois will be on September 14, 2099 and just clip the northeast corner of Illinois and Chicago.

It’s important to know that a solar eclipse at even 99% totality is completely different from 100% totality. The sun is so bright that even with the Moon blocking 99% of the sun’s light, it is still unsafe to look directly at the sun and the light is similar to that of a late evening. Also, the closer you are to the center line of totality, the longer the total eclipse will last—just over four minutes.

Safely Viewing the Eclipse

Until totality, the only safe way to look at the partially covered sun is indirectly using a pinhole viewer or directly through special-purpose solar filters (such as “eclipse glasses”). If you are purchasing eclipse glasses, you will want to ensure that it says it meets the ISO 12312-2 International Safety Standard. You’ll also want to check your eclipse glasses to ensure that there are no scratches, punctures, or tears in the solar filter. Any damage will let through too much sunlight and damage your eyes, so damaged glasses should be thrown away. Other safety measures include:

  • Always supervise children using solar filters.
  • If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld viewer in front of them.
  • Stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright Sun. After looking at the Sun, turn away and remove your filter — do not remove it while looking at the Sun.
  • Do not look at the uneclipsed or partially eclipsed Sun through an unfiltered camera, telescope, binoculars, or other optical device.
  • Similarly, do not look at the Sun through an unfiltered camera, telescope, binoculars, or any other optical device while using your eclipse glasses or handheld solar viewer in front of your eyes — the concentrated solar rays could damage the filter and enter your eyes, causing serious injury.
  • Seek expert advice from an astronomer before using a solar filter with a camera, telescope, binoculars, or any other optical device; note that solar filters must be attached to the front of any telescope, binoculars, camera lens, or other optics.

Other Eclipse Resources

The 2024 total solar eclipse may be a true once-in-a-lifetime event for many people. Make sure your experience is safe, and plan on significant traffic both into the path of totality before the eclipse and out of it after the eclipse has passed.

Photo © 2017 by O’Dea at Wikimedia Commons under Creative Commons license.