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 saw the same cresent effect in Bradenton Florida at an 85% level of eclipse. Quite amazing.
This is very interesting, – as my grandson just mentioned that during a total eclipse, people see lots of strange ‘worms’ wriggling about on the ground. Well, this lense-theory explains it all. The small ‘pinholes’ between the leaves on the tree all make a ‘Camera Obscura’ – effect, and project the image of the eclipse onto the ground nearby! Nature is Fantastic.
Actually they are different than the crescent gap shadows. They are called shadow bands and why and how they occur is still being debated. https://en.wikipedia.org/wiki/Shadow_bands
As I surf around the shortcuts I have on my desk top, I stopped at:
:http://www.stonepages.com/home.html
Your photos of the crescents from leaf shadows reminded me of all the cup and ring
carvings on a great many upright stones in the British Isles and Europe.
I got the same effect with a cheese grater.
Nice, I did a similar thing with the last last eclipse in Europe. I had a clump of bamboo which was nice because the hole and thus the crescents were more spaced out. Also nearer the ground so more sharply defined.
I was very excited until I realised I did not have a film in the camera !!
Because it all passes so quickly I did not time to reload.
Do you have a larger version of the first image. It may be interesting to use deconvolution using the crescent to see what shadow a point source would have made.
We had the same effect in Silverton, Oregon, where I travelled to be in the path of totality. I shot a couple of pictures of it; here’s one: http://www.tobynixon.com/images/eclipseleaves.jpg.
By the way, the tree in this case was a large maple or similar broad-leaf tree, about 50 feet tall, at the edge of the parking lot where we were parked. The sun was more-or-less directly over the tree during the eclipse, so the shadow was right in front of us. This effect was completely unexpected.
Great picture. Thanks.
I put up a cheap plastic tarp to keep the direct sun from pouring in through my office windows every summer morning. I thought briefly about cardboard, too – then realized the tarp had weathered enough that it was full of pinholes. Didn’t even need a piece of paper; since the tarp has to be folded up at the bottom, the inner side was a perfect projection surface.
I did take a look at the ground under the one leafy tree (actually an overenthusiastic bush) that we have in the back yard – not nearly as clear.
Some folks at my workplace did The same thing by crossing their fingers at right angles with a gap between all fingers. Made a nice overlapping set of crescents on the ground during the eclipse.
Is this from Susielindeau.com?
😕 Server not found 😕
I saw it on a building right across the street from my house. There was a woman standing nearby using her phone to view the eclipse,not seeing the silhouette right behind her.
Isn’t it amazing what conscious awareness can achieve. If only we all could accomplish so much in all our daily lives; think of all the wonders we would no longer miss. Perhaps some could even recapture the joy of life … nah .. they’d probably rather wail with their tales of gloom and doom and CAGW … their loss.
I remember seeing that effect with the partial eclipse on Melbourne in the mid 80’s. I had carefully made a pinhole camera and didn’t really need it though I could project the image onto white paper. I’ve never had the good fortune to be in the right place for a total eclipse; always the wrong side of the world when it happens.
The images through the leaves are beautiful, especially in the first photo.
The ABC (in Oz) did something useful for a change and provided an interactive map of Oz and a globe showing when and where upcoming eclipses will occur:
http://www.abc.net.au/news/2017-08-22/total-solar-eclipse-when-where-australia/8813250
Head to Sydney in 2028 for a total, or parts in the US in 2024.
The best way to save your retinas if you don’t have glasses is to observe an eclipse by looking at its reflection on water. And if your feeling extra ‘nerdy’ (c’est moi) you can use a magnifying glass to check out the reflected sun/moon…
where does that idea come from. Reflection will polarise and thus loose some intensity but it can still blind you. Just look at the sun reflection on a normal day : it HURTS. That’s nature’s way of telling you you are doing something bad to your retina.
Very cool – would make for some great wall-paper for the computer 🙂
Here in N.E. Ohio my family used two 1950’s Polaroid camera lenses in
combination with standard sunglasses. We could rotate the lenses to
almost any level of obscurity we wanted.
We also did the old trick of casting little crescent shadows on the sidewalk
running the sunlight through the bottom of a stainless steel colander.
Mighty cheap entertainment !
Very beautiful images. I noticed this half a lifetime ago with the round images. I showed with a thermometer (you need a non windy day) that the sun images are basically the same temperature as the shade itself because the only heating element is the amount of sunlight passing through the pinhole. The apparent arcs of crescent aren’t from motion of the image. Check today and you will see such clustering effects.
I have done this for years. I posted in the eclipse threads over the past few days, advised, a Louisiana teacher on it when he posted on WUWT on what to do for his students. I’ve asked Anthony on his recent thread how to post cell phone pictures on the blog and didn’t get much response, although I’m now travelling and haven’t checked thoroughly to see. I also have the photos of the round images from an earlier photo shoot of the phenomenon
I’ve shown students how to calculate the diameter of the sun using the round images under the tree and proportional triangles.
From your image sizes I would say you were under a fairly tall tree, more than ten meters to the pinhole for a decent – sized image of 10cm (4″).
Going back outside to look, the canopy above extends from about 25-40 feet up. Good rough estimate on your part.
My son in LA used this technique and a lady asked if he was a sidewalk inspector since it was about time that something was done to the sidewalk. He told he he was watching the eclipse, and she said “well you are looking the wrong way” and walked off.
This is the result when using a colander. https://www.facebook.com/crowcanyonarchaeologicalcenter/photos/pcb.10154700654607466/10154700642467466/?type=3&theater
Very nice!
Very cool
Wow that is cool!
We saw it in Texas. Our oleander made a perfect viewer.
Alec: A great observation and a lovely photograph.
Everyone: Next time you look at the dappled orbs of sunlight dancing on a forest floor, know that these too are the focused images of the sun.
Right. I was thinking that. It is only revealed when there is something distinguishing about the face of the sun.
Fantastic! Thank you for sharing this.
These natural pin hole cameras were what I was anticipating, but confounded by the diffuse light through the overcast. Was the overcast caused by the cooling of the eclipse? I think so.
I think not. We were in the path of totality, and throughout the early afternoon clouds were building to the south. After the totality, and the cooling, I noticed that the clouds were visibly smaller. However, they quickly rebuilt afterward.
Inverted binoculars used as a projector worked well for me. Very easy, no prep.
These photos show the crescent sun projected on the ground through the trees in my yard, by the pinhole camera effect. It looked like God painting sun-dappled shadows in the French Impressionist style.
http://sealevel.info/IMG_20170821_144726_cropped1_40pct.jpg
http://sealevel.info/IMG_20170821_144657_cropped1_40pct.jpg
Eliza pup didn’t seem as excited about it as I was.
Very near totality. Nice.
About 93% here, apparently.
My brother got the same effect on his camera here in Salt Lake City, UT–91% eclipse.
I was on my Atlanta-area front stoop using a Ritz cracker box pinhole projector to observe a clear but tiny image when I refocused slightly and saw this same effect a few feet away. Once again, my ingenuity easily bested by nature!
I used a monocular, gaff-taped to a camera tripod, projecting on a piece of printer paper. Shaded the paper with a shipping envelope with a hole cut in it, placed around the monocular. Completely kludged, but it worked pretty nicely once I held the paper up to the right spot to focus.
At Santa Fe College in Gainesville FL we set up a large Celestron telescope in the forecourt of the Planetarium, and projected the image of the sun and moon onto a white screen. Huge crowd of interested visitors as the sun, sun spots, the moon moving over the sun (to 87% of totality here), and even the jagged edge of the moon’s image caused by the mountains of the moon. Then we turned and looked behind us at the shade of the trees on the sidewalk, and there were all those perfect crescents. The public was enthralled.
The remaining sunlight was washing out the image, so I ran to my car and got an umbrella, and my job became holding the umbrella over the screen. I explained to the crowd about all those years in graduate school learning how to do that.