Analemma - a trace of the annual movement of the Sun on the sky - is well known among experts of sun-dials and old Earth’s globes as a diagram of change of seasons and an equation of time.
The photographer took a picture of the sun in the sky at the same time, every 10 days, on a single frame of film. He only had to postpone the exposure time twice, due to bad weather. To keep the camera in the same position, he attached it to a platform that he could mount and dismount.
Very impressive.