Guest post by Alec Rawls
With a weak sun well up in the clear blue sky yesterday morning I was thinking I should go punch a hole in some cardboard and project an upside down image of just how far sun was being eclipsed by the moon. Then I looked down and saw this:
Wow, about 95% eclipsed. On the Olympic Peninsula, 200 miles north of totality, this must have been about the peak. Small wind-driven movements in the leaves above are presumably why some arcs show up as thicker than others (notice the bit of blurriness in the non-instantaneous arc images). Bigger leaf gaps, being less pinholey, will also enlarge and distort the “pinhole” images. Thus the thinnest arcs would seem to provide the truest representations, coming from smaller leaf-gaps and showing less leaf movement.
Did anyone else see this leaf-gap pinhole-image effect? I wonder how many prehistoric humans saw it and what they pondered about the coincidence between these unusual shadows on the ground and the weak sun above. There are many places where trees overhang flat bare rock surfaces, especially along rivers where humans have often resided.
Confirming inversion
A short while later the leaf-gap images showed eclipse-coverage at more like 80%:
West is to the left in this picture, verifying the inverted nature of the pinhole images. Just as the earth rotates towards the east so does the moon’s orbit proceed between the earth and the sun from west to east. It turns out that the eclipse shadow passes across the surface of the earth faster than the earth rotates so the shadow proceeds along the ground in the direction of rotation, from west to east. If the ground moved faster than the shadow then the path of totality would proceed east to west along the ground but the moon would still exit totality towards the east.
I did not have eclipse glasses but for those who did, this is what you all observed, correct? That the moon departed totality towards the east? In the leaf-gap pinhole image above the shadow cast by the moon is seen exiting stage west, confirming that the eclipse-image is flipped.
And that is how I saved my retinas, August 21, 2017. Thank you momma nature. I just regret I wasn’t more systematic in recording the progress of the leaf-gap inverted-eclipse-image phenomenon. Next time somebody should get a full sequence of pictures.
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I witnessed totality in Russellville, KY, and I enjoyed pointing out the crescent shadows to passers-by while we were eagerly anticipating the big moment. Got a few good photos too.
Out in the Shirley Basin there were no nearby trees to make these shadows, so I showed my kids that crossing one’s hands with slightly opened fingers does the same.
I saw this pattern on my brick walk, under the shade of a large sycamore tree in Orange county NC. It was not evident on the adjacent grass. Then I went inside and saw the same pattern projected through West-facing windows inder the,shade of the same tree. It was very cool and unexpected, and I wondered how many others were reaping the rewards of looking in other than the consensus direction.
Should have read “projected onto translucent window shades” through West-facing windows,……
Orange County, NC, eh? Hi, neighbor!
Don’t miss Prof. Will Happer in Chapel Hill on Sept. 12th:
http://www.iconlectureseries.com/
You can create the same effect with your fingers. I showed a bunch of folks how to do it and they all loved it.
You simply extend our two longest fingers on both hands and cross them to make a little tic-tac-toe board with their shadow. The little squares of light on the ground display the same effect.
very cool, thank you
We saw that in spades at our ocean front park while using our pinhole viewer. We actually saw two types. The seagrape trees produced random pinhole images like those in the post. But the coconut palms produced double rows of aligned images where the closely spaced frond leaves met frond stems. Quite magical. And when the temperature drop kille the sea breeze, very crisp because still.
The eclipse gave us a much-needed break and distraction from the crazy hatefulness which has gripped our nation. Cool picture! Enjoy being back in the 17th century!
Yes, I saw the same, projected on a white wall, thru a shade tree, it was neat.
I did the pinhole thing at first, recreating what we did in elementary school during the eclipse in the 70s, but then found that my cell phone camera projected a perfect eclipse image. I used the patio umbrella to shield my eyes.
https://flic.kr/p/XNaedR
I did a little research and this is how it works:
https://photo.stackexchange.com/questions/92059/why-a-partial-eclipse-is-apparent-only-as-an-artifact-on-a-smartphone-camera
It even worked when the clouds covered the sun…
https://flic.kr/p/WLY6E2
The same effect can be done with a collender/pasta strainer. Showed the kids this on Monday off and on during the eclipse. It was nearly as cool as the special glasses.
While everyone else was looking up through safety glasses, I always look down during partial eclipses. I love to walk under the trees to see the crescent shadows, to make pin holes with just my hands, and look at how funky the edges of some shadows become.
Very cool –thanks for sharing.
Spotting scope worked great…
https://www.facebook.com/photo.php?fbid=10156204913378812&set=pcb.10156204914083812&type=3&theater
I’m testing a photo upload from postimage.org.
I’m thrilled. Thank you Tony L. Casper, WY monday, one of the many shots I got.
In Colorado with 90% occlusion, There was a point during the sun’s re-emergence when its light resolved details of leaves against our paito pavement with incredible detail, to the point of showing serrations on our maple tree. The interesting thing, in hindsight, is that I’m not positive about whether the latter detail was just a product of my imagination, as the cool wind was causing the branches to wave about a little, but I could definitely distinguish maple and locust trees by their shadows for a certain period. Prior to that, what had been so noticeable had been the crescents.
Looking down during an eclipse has its merits.
After reading your post discussing the evolving quality of shadows you saw, it occurs that light that penetrates more distinctly through the gaps is laser-like, more focused and intense than when the sun’s light comes from its full face, which must cause a lot of diffusion. I’ve never seen anything like it.
I planned on looking up too, but MacDonalds didn’t have a pair of those glasses when I went in. Er, Monday. About an hour before. Had to buy a quarter pounder and fries as solace.
No word yet, on Boulder’s emergence. Anyone? Anyone?
Thank you Alec for the multiple image post under the partial shade tree that I had notified people to look out for who couldn’t travel to the line of full eclipse. Your point about the relative motion of the moon’s shadow coming at us from the west (as the moon overtook the sun at about 12 times its own slower single degree per day along its “ecliptic” course among the stars that actually just reflects our own earth orbital viewing point) gave a back of the envelop average calculated speed from west coast to east coast of about 1600 miles per hour during its hour and a half traverse. This equivalent of a Mach 2 jet fighter or the velocity of a rifle bullet arrival of the dark lunar shadow upon those experiencing the full eclipse was as you say the product of an actual Mach 3 speed across the surface of the globe diminished by our own planetary rotation of eastward of around 700 miles/hr. for U.S. latitudes.
In the 1960s, my brother discovered that the best place to was the partial eclipse was in a silver maple tree. Besides being a good climbing tree, the deeply lobed leaves made very good pinhole cameras and we could adjust the density of images by climbing higher or lower.
I mentioned it in my solar projection page http://wermenh.com/eclipse/
So you discovered what the ancients knew 7200 years ago. And made a megalithic calendar out of it. A lesson for us all.