Feeling a little light-headed today after staying up late to watch last night’s eclipse? Me too. But it was an event worth every minute. I outran the clouds by driving east into Wisconsin and setting up on a sandy road on a beautiful night. Temperature 71°, mostly clear and the moon doing its thing. My favorite moment happened just before it slipped fully into shadow, when that narrow, brilliant rim of sunlit moon remained like a polar cap on a red world. Fantastic.
Totality seemed dark to me. Astronomers rate lunar brightness and color using the Danjon Scale numbered from “0”, a deep brown-red very dark eclipse to a yellow, shiny “4”. This was a “2” in my eyes. How would you rate it? (See below for the scale) During totality, the return of night was dramatic. Even though I’ve seen my fair share of eclipses, I couldn’t get over how many stars popped into view. If you looked at the moon in binoculars, they dotted the field like ornaments on a Christmas tree.
The top or northern part of the moon passed closest to the center of Earth’s umbra — the dark, inner shadow cast by the planet — while the lower right or bottom rim passed closest to it outer edge, the reason it appeared brighter to the eye. It so happened that the darkest part of the moon coincided with a large, dark volcanic plain called Oceanus Procellarum (Ocean of Storms), enhancing the overall duskiness of that region during totality.
Did you have a favorite part of the eclipse? Besides the return of the starry firmament, lunar eclipses feel majestic, like the unfolding of a long, slow movement in a symphony. From quietude the music builds to a powerful crescendo before returning to a hush.
Here’s the Danjon scale along with a naked-eye guide:
L=0: Very dark eclipse. Moon almost invisible, especially at mid-totality.
L=1: Dark Eclipse, gray or brownish in coloration. Details distinguishable only with difficulty.
L=2: Deep red or rust-colored eclipse. Very dark central shadow, while outer edge of umbra is relatively bright.
L=3: Brick-red eclipse. Umbral shadow usually has a bright or yellow rim.
L=4: Very bright copper-red or orange eclipse. Umbral shadow has a bluish, very bright rim.