Hello Sky Story, this is Gordon Telepun, the primary author of the second paper you cited on shadow bands. I have viewed shadow bands at 4 of my 6 total solar eclipses. Thank you for citing our work. I think you understood our conclusions reasonably well. I think it is great that you posted your video of shadow bands, which is quite good, and you were so fortunate to have the condition of snow on the ground, which provided that large white background for you. I am glad you are excited about them. Viewers of this video can also search KZread for a great shadow band video on the snow in Svalbard during the 2015 eclipse. There is a lot to unpack here, so I will make some comments in no particular order of importance. First, I would say that one has to be cautious when using the terms scintillation and seeing interchangeably. The twinkling of a point source, stars, to the naked eye, is generally considered scintillation. This is often written about as being a very high atmosphere effect. Often, astronomers use the term seeing when discussing the telescope view of an object, and then aperture comes into play. It can get complicated, so I am just saying they are not exactly the same, so be careful. In my research on shadow bands, the one thing I'm afraid I have to disagree with is that the final thin crescent of the Sun behaves as a point source. It simply is too large in the sky to be considered a point source (like a star? no). I think that this sized illuminated object behaves like observing a planet when considering atmospheric turbulence, which I would categorize as seeing. I disagree with the graphics in this video that show the final crescent Sun behaving like 5 point sources in a row. That is mixing together two optical theories. And shadow bands can start 120 seconds before C2 and I saw them last about 3 1/3 minutes after C3 in 2019, so that is now a pretty thick crescent. Meaning it does not always have to be a very, very fine slit. You start to see shadow bands because of the mix of two things happening simultaneously: the crescent has to be thin enough to potentially cause them, and as the crescent is getting thinner, your ambient light at ground level is getting low enough that you have a chance to see the low contrast gray shadows. For argument's sake, let's propose that shadow bands are actually getting created 10 minutes before C2; fine, but you would not be able to see them on the ground because the ambient light is too bright. So it's a mix of those two conditions. The size/length of shadow bands on the ground always has a relationship to the length of the crescent in the sky and the altitude of the eclipse in the sky. Shadow bands are always in rows because no matter how they are caused, they represent the shape of the thin crescent. The rows, if they move, will move together in parallel. The movement is what helps you spot them. They can move to your left or right, towards you or away from you. Sometimes, the rectangular shaped shadows will also undulate within the rows, which makes them appear like snakes, or the rectangles can appear to leapfrog each other. Then, rows can move slowly or rapidly; I have seen both. Shadow bands generated by a low-attitude crescent are longer than shadow bands created by a high-altitude crescent. I saw this myself with shadow bands in 2019 with an eclipse at 11 degrees above the horizon (elongated) and is seen in the video from Svalbard (elongated). In the video presented here, I am surprised they look as long as they do, with this observer's eclipse altitude being about 33 degrees in the sky. However, the key thing missing from this video is compass directions. It would be beneficial to know the direction of the path line across the snow field and the direction of North for reference. The importance of my paper is that I had shadow band videos from the same eclipse, at three sites along the path, all marked with compass directions, in the same general region of the path, with the same general southeastern summertime weather pattern. Data like that has never been collected. However, the shadow bands at all three sites behaved completely differently. At one site, the angle of the rows even changed by approximately 30 degrees between the C2 shadow bands and the C3 shadow bands. At one site, the rows moved rapidly toward the direction of the umbra approach while being perpendicular to the line of the path. At one site, the rows had very slow movement. At the 2024 eclipse, I saw rows of shadow bands that were perpendicular to the path but moved rapidly in the direction of umbra exit. So, with my experience of seeing shadow bands and researching them, I think this: I don't know exactly at what layer of the atmosphere causes them, but I believe it is lower than most other theories predict because I feel that the behavior/motion you see at your observing site is a representation of lower (thicker) atmospheric turbulence. I have two very in-depth shadow band videos on my KZread channel called Solar Eclipse Timer. Thanks for posting your video!

@SKYST0RY

2 ай бұрын

Hello Gordon. Thank you for posting! I had attempted to contact you via FaceBook and a couple sites, hoping to confirm some things before posting this video. Your paper was great. I thought it was especially intriguing the way the sb showed different directions and patterns of movement between the three sites 176 miles apart. I wish I had thought to put a couple directional arrows into the video to show direction. If you imagine the screen split in half, from the center, go about 20% to the right, and that's where the sun was. In the case of my observation, the sb appeared to radiate almost direction from the direction of the sun. Using Stellarium, I backdated to April 8, 2024 and find the sun sitting at just over 32 degrees, so your estimate is almost exact. At this point, the sun is approximately 25 degrees south of west. The geographical location of the observation was approximately 10 km N or Kouchibouguac, New Brunswick. For anyone wishing to visit Dr Gordon Telepun's KZread channel, Solar Eclipse Timer, it is at: youtube.com/@solareclipsetimer

@DGreensleeves

Ай бұрын

They were moving north in my observation from the start of the eclipse in Dallas. The same direction as the eclipse was moving and perpendicular to the event. The were snakelike and moving pretty quickly.

Thank you for this video! My son-in-law noticed these while we were viewing the eclipse in Dallas, Texas and his comments about them were captured on a video my daughter recorded during the eclipse. I did not see them but several other family members did. His observations were correct and my explanation was not. I am excited to share this video with him!

Congratulations on capturing this interesting phenomena. I wish I had made more of an effort to observe it during the last eclipse, but I was in an environment which would not be conducive to their appearance. When I was making telescopes 40+ years ago, there were many optical tests which used an optical slit. This was usually 2 razor blades separated by a small space with the blade edges parallel and a light source behind the slit; one example would be a Foucault test. In such tests, mirror surface features, air disturbances, heat, etc. were greatly magnified. I would postulate that the moon is effectively creating such a razor's edge and perhaps the sun's limb could act as the parallel edge (effectively parallel due to the diminishing illuminated space and distance of the subjects). The motion of the moon would vary the slit's width and the sensitivity to magnification (probably of our atmosphere). I wonder how the apparent velocity of the bands compares with the trigonometry of the earth, sun, moon triangle.

@SKYST0RY

2 ай бұрын

I think Codona had theoretically ruled in the moon creating a narrow slit of light that could be refracted by the turbulence (seeing) in Earth's atmosphere, but had ruled out influence of the sun's limb. Or, rather, he stated that theory indicated the limb's effects would be too minimal to bother to calculate. But Codona's work was all theoretical.

Great capture! I saw shadow bands watching the eclipse from Rogersville.

Great video. I did not see shadow bands in 2024. But I did see them in 1979 (feb 26) in Brandon Manitoba (across the snow)

Great video. I got some from Miramichi. What a sight.

Thanks for this video and narration. We were very close to you on the beach at Point-Sapin and did not notice shadow bans. There was no snow on the ground. I think it was in the year 1972 in Halifax where I recall a very different experience from Citadel Hill. The totality seemed to come over us in a sudden wave and ended as if a light had been turned on. Perhaps depending on your location and surroundings the effects of a total eclipse can vary.

@SKYST0RY

Ай бұрын

I believe the more directly overhead the sun is, the faster totality will come on but the less likely you are to see strong shadow bands. The last eclipse was very favorable to us, with the sun pretty low as the eclipse occurred at our location in NB at 1634.

We had a sheet spread out and could see them in Missouri. Love your channel.

planets will reflect off a calm body of water at night, but stars will not

Superb!

Hi, I saw the shadow bands on the ground in Dallas (did not see the in Charleston in 2017). I thought I was hallucinating for a second and pointed them out to my girlfriend who saw them too. I had not studied eclipses enough to know these were part of the phenomenon. They looked like golden "frequency measurement waves" squiggling and chasing each other across the ground. I could see them on grass but we were walking to a flat parking lot and could really see the there. - My attempt to video on my iphone came up with zip. I googled later and found out about shadow bands. Just another magnificent memory from being in the path of totality. Thank you for the video!! And everyone posting on here for the research and comments. Did the waves have a color when you were looking at them?

Beautiful footage, and thanks for sharing! I traveled to a spot a little ways south of Fort Worth, and had clear skies (although only just!) for totality and the surrounding minutes. My group and I observed some very interesting ground-based phenomena prior to totality which I think fit into the range of descriptions of shadow bands, but I'd love to run it past an expert. Sadly, we did not record video of the effects - I was unsure if this would be the last total eclipse I would see, thus I spent my time just staring at it and didn't worry about photography. However, due to the particular specifics of the location and its geography, I can reconstruct what we saw, together with four people's independant observations. Let me know, and @solareclipsetimer I'm also happy to share with you.

@SKYST0RY

Ай бұрын

I would love to see them though I don't consider myself an expert. I just had the good fortune to be in the right place at the right time with the right kind of camera.

Very interesting with very reasonable explanations for what may cause the shadow bands, but I did not hear (may have missed it) how any of those potential reasons would explain the observation of the shadow bands moving at about 1.8m/s.

@SKYST0RY

2 ай бұрын

I think I covered it toward the latter third, but the answer is there is no good explanation and the 1.8 m/s speed estimate is up for debate. Other papers listed whole ranges of speeds from slower to much faster. I didn't cover them for lack of time. The apparent movement of the sb remain something of a mystery and Telepun's measurements and angles showed it probably mostly depends on high altitude winds. I did not feel either Telepun or Codona adequately explained it. My own thought on it is that probably at times (as in periods of very bad seeing) atmosphere plays the primary role in what we perceive. At other times, perhaps angle of moon, sun and Earth play the key role. For example, if the seeing is bad but there isn't much high altitude wind movement, the sb should writhe more and move less. If the wind is at speed, we should see more in the way of movement. Perhaps if seeing is good and wind speed is still, the key player is how the edge of the moon covers over the sun. It would seem many persons saw extraordinary sb during the last eclipse once the moon's umbra had moved northward. Perhaps when all the above factors come together we get very rare spectacular sb. That's certainly what we saw in the New Brunswick backwoods. But I'm only making educated guesses.

Nice video that leaves me with a question. If the shadow bands occur just before totality, are they occurring when the eclipse is not quite 100%? Are these bands also visible just outside the zone of totality where the 99.5 or 99.9 or whatever percent state required would last longer?

@SKYST0RY

2 ай бұрын

To the best of my knowledge, they are not optically visible outside totality, but beyond the human range they may occur. Shadow bands occur before we can see them and persist after, and may still be detected on instruments.

Fantastic treatment of the phenomena - thanks! We experienced them in a field in Miramichi: kzread.info9GkRUDFOh3k. I didn't realize that they only show when conditions are right. What a marvellous piece of the whole eclipse!

Weird.

@DGreensleeves

Ай бұрын

Indeed!

We live under "water".

They look like ripples of sunlight hitting our atmosphere the way a rock thrown into a pond would create ripples of water onto the surface of the water 🤷