Dimming of the light during the eclipse |
As promised in my previous blog post (“The Day the Sky Went Dark (sort of),” which was about the less-than-stellar partial eclipse on April 8, 2024 in the Philadelphia area, I am finally publishing an account of the much more dramatic partial eclipse on August 21, 2017. Both partial eclipse events were 80% sun coverage, but the event was ruined by cloud cover in 2024. The 2017 event occurred during a mostly clear, blue-sky day. The main reason I went to all the trouble to photograph the 2024 event in Philadelphia’s Laurel Hill Cemetery was because of the grand experience my friend Bob and I had in 2017, at Laurel Hill’s sister cemetery, West Laurel Hill Cemetery in Bala Cynwyd, PA.
Bob Reinhardt in Westminster Cemetery, prior to eclipse |
The sun being covered by the moon itself wasn’t so much the reason I was out to observe the 2024 event – you KNOW what’s going to happen, right? Everyone has a prescient knowledge of the event due to photos of past eclipses and you’ll see photos of this one after the fact. What I REALLY looked forward to was the light show on the ground, on terra firma.
When Bob and I experienced the partial solar eclipse in 2017, it was my first rodeo. I had no idea what to expect, it was like visiting a new cemetery, you know? All wide-eyed and wonderment. We’d both been to West Laurel many times, but today, everything looked … different. We were just walking around when the eclipse happened. We had spent a bit of time before the eclipse at Westminster Cemetery, which is next to West Laurel Hill. We had our safety glasses, as did the picknickers on the grass at West Laurel, seated on their red-and-white checkered tablecloth. They were staring into the sky through protective shades, surrounded by bottles of wine and sandwiches.
What was most stirring in the minutes of sun coverage was the quality of light on the ground. The way everything looked was virtually indescribable. But I will try. The photos you see here don’t really do it justice because as you may or may not know, under eclipse conditions there’s more going on that meets the eye.
Grand Canyon, by Rich Jolly |
Capturing the light during a solar eclipse is as difficult as photographing the Grand Canyon. Okay, bad analogy – my friend Rich Jolly did a pretty decent job of photographing the Grand Canyon. I, however, had a difficult time capturing the ambient light at ground level during the eclipse. Why did everything look so odd? Science News says, “During a total solar eclipse, the moon blocks the sun, so most of the light hitting and reflecting off objects on the ground is indirect light.” Indirect light casts no shadows!
Selfie with "Solar Viewer" - don't want to burn out those retinas! |
That was easily one of the strangest things. Before and after the eclipse, cemetery statues cast shadows due to their side illumination by the sun. But for the few minutes of maximum sun coverage by the moon – no shadows. However, other things happen …
The crowning moment of the solar eclipse |
According to Scientific American:
“[Observers experience] what is called the Purkinje effect, or a natural shift in color perception caused by fluctuating light levels. In bright light, colors such as red and orange are rich and vibrant to the human eye, compared with blue and green. But in dim light, red and orange become dark and muted, while purple, blue and green brighten. Sunlight’s rapid, dramatic dimming during a total solar eclipse can heighten this phenomenon, making such events all the more surreal."
Science News tells us:
“For a few minutes, as the moon blocks the sun’s rays, colors fade to silvery gray in the false twilight. Usually vibrant reds may appear dark or even black, while blues and greens will pop.”
Colors appear to fade at twilight, yes, but our brains handle this differently under those daily circumstances. Sunset is a gradual thing, as is sunrise, and our eyes (and brains) adjust so gradually to this color shift that we barely notice – unless its too dark to even discern colors. So you know, of course, that at night your eyes are less capable of discerning colors, right? Its all about our rods and cones.
According to Science News:
Dimming of the light ... |
So our eyes adjust from bright to dim light before and during a solar eclipse, then from dim back to bright after the eclipse, but this occurs unusually quickly causing our brains to wonder what’s going on.
Eclipse through the "Solar Viewer," August 21, 2017 |
This continued until about 4 p.m. when the moon ceased to block the sun. Shadows reappeared and colors shifted back to normal. The world brightened up. It was like experiencing philosopher Immanuel Kant’s phenomenal world while catching a glimpse of his noumenal world (a world we can never directly know, independent of our senses and cognitive faculties)(ref.).
What puzzled me was that my photos that day did not accurately record what I saw. Maybe because I don’t have a “Purkinje” exposure mode on my camera?
Science News also tells us that “More of that indirect light is easily scattered blue waves, so objects reflect more blue light. That causes an apparent shift in the color spectrum toward blue, Takeshi Yoshimatsu says [Yoshimatsu is a color vision researcher at Washington University School of Medicine in St. Louis]. Something similar happens in other dim-light conditions, like sunset.”
Chalk it up to the Purkinje Effect - our eyes’ sensitivity to luminance to shift from red to blue in low light. In Space and Astronomy News, Rafal Mantiuk, a computer and vision scientist at the University of Cambridge, says:
“This color effect won’t be visible in pictures... It’s a matter of perception, not just optics, so it has to be experienced in person. For those who want to see the Purkinje effect in action but aren’t in the path of totality, Mantiuk offers an experiment. Take a square of red cloth and one of blue and look at them in the light. Then dim the lights, maybe put on a pair of sunglasses and look again. The brightness of the squares should be reversed.”
So if you are alive for the next solar eclipse, I recommend spending it with the dead. The surroundings offer a staid setting, so you can experience the light show with limited distraction. Although it occurs to me now that a solar eclipse in a cemetery might be a prime setting to stage a theatrical production of Edgar Lee Masters’ Spoon River Anthology. You know, with ghosts of the dead townspeople popping up from behind headstones, lamenting their earthly trials. If timed properly, the eclipse can provide the light show.
References:
https://philly.curbed.com/2017/8/4/16091074/solar-eclipse-2017-philadelphia-view
https://www.scientificamerican.com/article/why-do-colors-change-during-a-solar-eclipse/
https://www.quora.com/How-can-we-exist-in-both-a-phenomenal-and-noumenal-world-according-to-Kant
https://www.sciencenews.org/article/why-colors-different-total-eclipse
During a total solar eclipse, some colors really pop. Here’s why - (spaceandastronomynews.org)