Longest photographic exposure time

The longest photographic exposure lasted for 8 years and roughly 30 days, from August 2012 to 16 September 2020. It was captured by photographer Regina Valkenborgh (UK) using a pinhole camera made from an old drinks can lined with photographic paper.

The camera was mounted to the dome of one of the telescopes at the University of Hertfordshire's campus observatory in Bayfordbury, UK, and captured the tracks made by the sun over the approximately 2,953 days it was up there. The image includes the dark shapes of the unversity's buildings on the horizon, including the slightly fainter outline of a building that was constructed half-way through the exposure, and a series of white arcs that trace the sun's movements across the sky. At the bottom of the image, the lowest arcs show the sun's path at the winter solstice, while the topmost arcs show the summer solstice.

Valkenborgh placed a number of drinks-can pinhole-cameras around the Observatory complex while she was a student, and used the resulting pictures in her work. The remaining can-camera remained up for so long because she forgot about it. It was taken down in September 2020 by the observatory's technnical manager, David Campbell, who needing to install some solar panels to the place where it was attached. He opened up the can to see if the camera has captured anything interesting.