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Our goal is to collect thousands of videos of solar eclipse #shadowbands!
You Should:
(1) Make a public video of #shadowbands,
(2) Upload your public video to the web, and
(3) Post your science data here.
#Shadowbands are wavy patterns of light that appear on white surfaces during the deep partial phases of a total solar eclipse.
#Shadowbands are safe to watch, and they disappear during Totality.
Plan Ahead: Visit our #shadowbands simulator and science data entry pages before the eclipse.
Equipment: You need a video camera on a tripod, and a large white surface facing the sun. Also, tie ribbons to a stick to show the wind.
Setup: Put the video camera on the tripod. Point the camera at the white surface, and away from the sun. Put the stick with the wind ribbons in the ground so they appear in the video.
Experiment: Start recording video 10 minutes before maximum eclipse. Stop recording video 10 minutes after maximum eclipse. Don't touch the camera while it is recording.
Upload:
Upload your public video to
or somewhere else on the web. Knomon.com only accepts links to videos stored elsewhere.
Report: Report your science data at knomon.com. Include a link to your public #shadowbands video.
Bonus Opportunity: Also be a Citizen Scientist for NASA! Download the GLOBE Observer Eclipse App to collect detailed weather data during the Total Solar Eclipse, a project from NASA’s Goddard Space Flight Center.
Whenever #shadowbands can be seen, it is still not safe to look up at the eclipse with the naked eye.
Parents! Tell small children to watch for #shadowbands on a white surface to protect their vision by safely diverting their attention away from the eclipse until totality.
Eclipse #shadowbands are visible in a wider path than the path of totality. If you aren't able to get into the path of totality, you can still watch for #shadowbands.
For example, the Gateway Arch in St. Louis is just barely outside the path of totality, making it one of the best places to watch #shadowbands rotate. This quick rotation will help scientists evaluate the effects of wind on #shadowbands.
Mysterious #shadowbands were first described over a thousand years ago. Scientists need more data about #shadowbands to verify existing models. We want to look into the unknown for hidden surprises!
Eclipse #shadowbands make the invisible visible! It is a little bit like looking at sunlight on the bottom of a swimming pool. As light passes from thin air into dense water, the pool's waves refract the light, changing the direction it travels. We live at the bottom of a swimming pool of air called "the atmosphere".
Every beam of sunlight that reaches the ground has passed through many parcels of cold air and warm air. Cold air is more dense, and warm air is less dense. Every change in air density causes light to refract. The light goes in a slightly different direction. This leaves a shadow on the ground where the light would have been, had the light travelled perfectly straight.
The #shadowbands become visible on a white surface only when the very bright sun becomes a very thin crescent. Usually the big round sun just washes out these subtle #shadowbands.
The following advanced experiments are very difficult. They require special skills, such as mountain climbing or launching a weather balloon. They would push the envelope of our understanding.
Are you a mountain climber? We could learn a lot about #shadowbands if several separate teams of mountain climbers make several #shadowbands videos at several different elevations on the same mountain. This would tell us more about how#shadowbands evolve as they pass through the atmosphere.
If all the #shadowbands videos look the same at different elevations, it could mean that #shadowbands are fractal.
A #shadowbands video that uses a mountain glacier snowfield as a white surface could capture large-scale #shadowbands if they exist. Huge #shadowbands would appear within 5 seconds of Totality if they exist at all.
The best mountains for the Alpine Shadowbands experiment are Mt. Jefferson in Oregon and the Tetons in Wyoming.
Do #shadowbands appear in the stratosphere? Ordinary #shadowbands seem to form in the lower troposphere within 2km of the ground. Nobody yet knows if #shadowbands also appear in the stratosphere. They could tell us about stratospheric turbulence.
A Weather Balloon launched into the stratosphere could answer this question. Dangle some white paper under the balloon, and arrange a pair of video cameras to watch both sides of the paper. Launch the balloon into the stratosphere during totality.
The Stratospheric #shadowbands experiment is a great scientific control experiment for researchers. It would also be amazing to watch the moon’s shadow from the edge of space.
Watch this video from 2012, recorded by Peter Agar in Cairns, AU, just after third contact.
Send feedback to our Shadowbands Observers facebook page.
A knomon is a pinhole gnomon.
A gnomon casts a shadow, and is the central post on a sundial. A gnomon has limited precision because its shadow fades quickly with distance. A gnomon casts an umbra, just like the moon casts an umbra during a solar eclipse.
A knomon casts a cone of light. The cone of light can be cast much further into a large dark room to make a very precise sundial. Put a piece of white paper in the cone of light to safely observe partial eclipses and even sunspots! A knomon is useful for finding local noon and true North.