In August 2012, Regina Valkenborgh created a film-lined beer can which was taped and/or glued on the side of a campus observatory at the University of Hertfordshire. Using what is called the pinhole technique, it captured the rise and fall of the sun for 8 years before being discovered. The film stayed in place until September of 2020, when it was removed.
Inside the can was what experts think is the longest solargraph ever created.
The University of Hertfordshire Observatory account said in a tweet:
“The photograph was revealed on the Observatory’s 50th anniversary year – having watched 16% of the observatory’s existence, 12% of the reign of Queen Elizabeth II, and 4% of the existence of photography itself.”
When asked about how she felt about the discovery Valkenborgh said:
“It was a stroke of luck that the picture was left untouched. I had tried this technique a couple of times at the Observatory before, but the photographs were often ruined by moisture and the photographic paper curled up. I hadn’t intended to capture an exposure for this length of time and to my surprise, it had survived. It could be one of, if not the, longest exposures in existence.”
Eight years of the sun rising and setting left us with 2,953 arced trails in the photograph.