Baily’s Beads

Seeing and photographing the eclipse was one thing, but simply soaking it in was quite another. I decided long ago that I did not want to be so busy taking pictures that I would miss totality. This is a common mistake, especially for first-timers like myself. In fact, the most common advice from experienced eclipse chasers to first-timers like me is: avoid taking pictures of your first eclipse. Of course, I ignored that advice. 😉
So, in order to take pictures AND soak in the eclipse, I employed a tracking mount for my telescope and a software program that controlled the affixed camera through a USB cable. The software used a script that I wrote to trigger the camera at certain times based on my GPS location and the predicted events associated with the eclipse. It sounds very complicated, but it really isn’t. With a little practice, I developed a script that worked really well and captured a wide variety of exposures before, after, and during totality. This automated the process of taking pictures and allowed me to soak in the experience instead of clicking the shutter. And, even better, I collected almost 500 images between the beginning and end of the eclipse. Needless to say, I’ll be busy for a while sorting and processing them all!
I mentioned previously that there were so many things going on that it was impossible to see and photograph everything. In addition to detailed views of the corona like I showed in my last post, another aspect of the eclipse I wanted to photograph is called Baily’s Beads. These “beads” are a string of bright points of light located on the edge of the moon just before or after totality. The beads are so transient that you have about five seconds at the beginning and end of totality to capture them. Not easy!
Baily’s Beads are named after Francis Baily, who was the first astronomer to describe the phenomenon. He first saw them during eclipses in the mid-1800s and his descriptions were so eloquent that people began to flock to view eclipses in order to see Baily’s Beads. In a sense, Baily began what we know today as “eclipse chasing.” Last Monday, those of us who witnessed totality were especially aware of our fellow eclipse chasers as we sat in miles of traffic after the event. Thank you, Mr. Baily!
Interestingly, Baily’s Beads result from the fact that the edge of the moon is not perfectly smooth like a billiard ball. Instead, the edge has a knobby surface similar to a golf ball or a basketball. The knobby edge, or lunar limb, is due to the craters and valleys that cover the lunar surface. As the sun grazes across the edge of the moon, light passes through the valleys, but is blocked by the tops of the craters. The end result is the bead-like appearance of light just before and after totality. Pretty cool!
The image I’ve included here is a nice rendition of Baily’s Beads, which are visible on the left side of the lunar sphere. This shot was taken about 3 seconds before totality. In addition to the beads, note that the dark edge of the moon near the beads is rough. I was actually able to capture the irregularities in the lunar limb! What a pleasant surprise to see that! As Baily’s beads appear, the red chromosphere and prominences may appear simultaneously with the corona. You can just see them in the image. I’ll talk more about them in the next post.
Gotta go, I’m exhausted after a long day of driving today on my way back home. Tomorrow night, I’ll be in Knoxville!😎
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