Analemma Project

For a long time I have been interested in photography. Astrophotography, the art of imaging the night sky, is one of the most beautiful ways of experiencing our place in the cosmos. One has to be patient, learn about one's camera and lens, find dark spots that offer themselves to this kind of observation and battle long and cold nights alone in the dark with just the stars above keeping one's company. I always thoroughly enjoyed these nights, be it in at home in the Black Forest taking my first images, in northern Sweden capturing the aurora borealis or visualising diurnal motion while in the Altiplano of Bolivia.

Now, I have set myself a new goal. Within this niche hobby, there exists a very special kind of image that is notorious for how difficult it is to obtain. It is taken during daytime and requires a whole year to complete. And the main character of this photo is a rather special star: our Sun. Throughout the course of one year, as the seasons change, the Sun perfors a dance across the sky. For us in the northern hemisphere, it reaches its highest elevation above the horizon at noon on the day of the summer solstace. Conversely, during the winter solstace it will appear lowest in the sky making this day the shortest of the year. On top of this variation in elevation, our star also exhibits slight changes the azimuthal angle at which it will be located as a consequence of the "equation of time", the difference between the mean solar time and the apparent solar time. If one manages to image the position of the Sun from the same location and at the same time of day at regular intervals throughout an entire year, one will see this dance manifest as an intricate figure of eight traced out by the Sun. The stacked version of this time-series observation showing the Sun's apparent trajectory is called an analemma. It is a fascinating way of visualising the obliquity and ellipticity of Earth's orbit around the Sun and the passage of time.

Here, I want to document the process of capturing such an analemma. I will go into some details about the planning, preparation and execution of the project. And, hopefully, I will able to present the successful result in the end.