THIS isn't a photo of a laser show. If you stood on a balcony and watched the sky over Wrocław, Poland, where this took place, you wouldn't spot these strange figure-of-eight patterns. To see them, you need a pinhole camera, rigged to make a year-long time-lapse photo of the sun three times a day.
Maciej Zapiór, a solar physicist at the University of the Balearic Islands in Palma, Majorca, and colleague Łukasz Fajfrowski built a pinhole camera and set it to make 1-minute-long exposures onto a single piece of photographic paper at 1030, 1200 and 1330 each day from 1 March 2013 to 1 March 2014. The resulting image shows how the position of the sun in the sky changes throughout the year: in the summer it is higher, in the winter lower. Its position also shifts horizontally, tracing a figure-of-eight path called an analemma. You might have seen a similar pattern drawn on world maps and globes.
The colour of the sun appears to change, not because of something happening in the atmosphere, but because of changes to the photographic paper due to the differing temperature and humidity throughout the year.
"I am interested in connections between science and art, and the aesthetic aspects in science," says Zapiór. "Solargraphy and especially the analemma project is an essence of that."
This article appeared in print under the headline "Solar light show"
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