LibGuides: Physics & Astronomy: Solar Eclipse 2024

Solar eclipse

On Monday, April 8, 2024, Muncie, Indiana, will be given a once-in-a-lifetime opportunity when the path of the total solar eclipse passes over our community.

This is the first total solar eclipse to visit Muncie since 957CE!

For about 3 minutes and 40 seconds, Ball State University will be plunged into deep twilight as the Moon hides the Sun from our sky.

A message from the American Astronomical Society: Beware of spending totality with your eye glued to your camera’s viewfinder. Taking pictures is fine, but make sure you take time to appreciate what is truly a total sensory spectacle. If you’re using a telescope to examine the stunning detail in the corona, pause for a few moments, look away, and absorb the surrounding vista.

The key to not becoming overwhelmed by the sight of totality is to create a short list of what you really want to see and do, memorize it, and stick to it. Otherwise, you’ll spend your time gaping at the hole in the sky, and totality will fly by as if it lasted only seconds.

More information on solar eclipses & events:

Stages of the eclipse (C1-C4)

Points of contact
C1 - beginning of eclipse when the moon first touches the sun's disk (Bailey's Beads)
C2 - annular phase when darkness begins just before totality (Diamond Ring effect and Shadow Bands)
C3 - annular phase just after totality (Diamond Ring effect and Shadow Bands)
C4 - the last point at which the moon touches the disk of the sun; end of eclipse (Bailey's Beads)

Partial eclipse effects/phenomena

Animal and Human Behavior
As the sunlight dims, you may notice animals, birds, and insects acting in a peculiar manner - birds may flight home, crickets start to sing, bees land on the ground, etc. Many start to settle in as if night is falling; this is much more likely to happen at a total solar eclipse than at an annular eclipse.
Bailey's Beads
Caused by shafts of sunlight shining through deep valleys on the lunar limb (edge), they look like a series of brilliant beads popping on and off. They appear just prior to second contact and just after third contact at annular and total solar eclipses. They’re named after the English astronomer Francis Baily, who first described them during the annular eclipse of May 15, 1836. Stages: C2 and C3.
Diamond ring effect
A single Baily’s Bead, shining like a brilliant diamond set into a pale ring created by the pearly white corona. It’s the signal that totality is about to start (C2) and you can remove your eclipse glasses or solar filters. This occurs again as totality is ending (C3) which means you must use your eclipse glasses and filters again.
Pinhole cameras & projectors
Shining a light through a small hole produces a small image as though it passed through a lens. This provides a safe way to view the eclipse without looking directly at the sun. You can use anything with holes: colanders, mesh hats, your hands, etc. The shadows from leaves on trees will produce pinhole camera effects. See link above for instructions on how to make one.
Purkinje effect or shift
Depending on the intensity of lighting, we see colours differently. The wavelengths of light the human eye is sensitive to vary with the intensity of light, an effect known as the Purkinje effect. In lower intensity lights, peripheral rod cells are stimulated and the eye’s peak sensitivity to light shifts towards green in comparison to a peak sensitivity to yellow for vision in daylight. For example, in twilight, a red flower may appear black and objects in moonlight may appear greyish-green. (from IOPSpark) Usually, the switch happens more slowly with sunsets and sunrises or more quickly when we switch lights on and off or walk into a dark room but, during a solar eclipse, this effect can be observed more readily, especially after C3.
Shadow bands
Very faint, shimmering ripples of dark and light moving across the ground, walls, or clouds. These hard-to-see bands result from atmospheric “twinkling” of the thin solar crescent just before C2 and/or just after C3. When they occur at all (they're not reported at every total eclipse), they’re best seen against a white background.