Friday, July 12, 2024

Eclipse Solargraph


Mansfield, Connecticut, looking to the south, April 8 to June 20, 2024.

 My solargraph of the 2024 eclipse, plus the next two and a half months through the summer solstice, turned out pretty well, but I'm not sure if I can really make out any eclipse dimming. Theoretically, the lowest sun track in the sky includes the April 8 partial eclipse, but it kind of blurs into the sunny days in subsequent, higher tracks. Plus, the sun is off the top of the picture in the early afternoon, when the eclipse probably was starting, because the camera wasn't pointed upwards enough. 

In the solargraph, permanent, stationary objects in the landscape, like trees, are visible in the lower part of the image, while the sun's paths in the sky over the course of the exposure are the arcs in the upper part. Sunny days show up as bright arcs, while cloudy periods (or eclipses?) leave dark bands. 

The solargraph was made in a soda-can camera obscura with a pinhole to project an image onto a sheet of black and white photographic paper. The actual physical photograph is an upside-down and backwards, pinkish-sepia negative image, burned into the emulsion on the paper. I used a flat bed scanner to digitize the negative, then inverted the colors and flipped the image to get the bluish positive image above. Solargraphic originals apparently can't be developed in the usual chemical way, because the emulsion has been exposed to enough light that it would just turn solid black. There are practical instructions online if you want to try solargraphy yourself. 

Scan of the original negative image.