sunThis picture was taken by astronomers of a solar analemma, though at first glance it looks like an overexposed mistake. However, specialists know how very unique and hard these images are to capture.

Maciej Zapiór and Łukasz Fajfrowski have been taking photos of the Sun every day of the year using a primitive camera and elements from an old printer. They took three (yes, only three) photos. One was published by NASA. The technique they used is called “solargraphy.”

What is solargraphy?

Solargraphy is a technique which uses a fixed camera with a pinhole in order to expose photographic paper for a very long time – usually at least six months, but sometimes more than year. It is most often used to show the Sun’s path across our sky over the course of the year.

The equipment used to take the pictures is extraordinary (and extraordinarily simple). Scientist take a can and, using a small needle, they make hole in It which functions like a lens. Inside the can they put one page of photo paper, protect the “camera” with black adhesive tape, and then mount it on tree or pole. Then they have to wait a few months in order to capture the entire image, but it’s certainly worth waiting, because the effect takes one’s breath away.

The picture that is created over the course of this period of time shows the exact movement of Earth around Sun each day, and it looks a little like a figure 8 (the two solid lines that you see at the lower left occurred due to a timer switch failure that left the pinhole shutter open).

“It’s not very complicated, but it requires a lot of patience,” notes Fajfrowski.

Breaking down the technology:

In astronomy the analemma is really just the curve that represents the changing angular offset of the Sun (or other celestial bodies) from a certain point of view (Earth, in this case). The solar analemma has a shape of the number eight, thanks to connection between the Earth’s movement around the Sun and the slope of our planet’s axis to the plane.

To achieve the effect seen above, the exposure has to be done each day of the year at the same exact time of day. The exposure only lasts one minute.

To ensure the Sun’s light gets inside the can at the same time, scientists needed to create a special module. They connected a small engine from an old printer, a micro-controller, and a processor in order to develop a simple system to open and close the pin. They had a lot of problems on their way to success, such as few seconds delay in the system, but fortunately they managed to deal with them and capture the desired shot.

“We decided not to take many pictures and then superimpose them one on another, like people have been doing up till now. We used one piece of photographic paper for a whole year. That’s why the picture has such an intense effect” explained Fajfrowski.

Analemma can be taken from other planets as well. The Martian lander “Opportunity” was taking photos of the Martian sky for the whole year, creating analemma which shows the Sun’s movement from the Red Planet. It looks like this:

Image credit: NASA
Image credit: NASA

Not many people around the world have taken this kind of photo – sometimes the Sun hides behind clouds, sometimes the equipment doesn’t work in the desired way. If you have a lot of patience (and a lot of free time) maybe give solargraphy a try.

To see all photos and read more about the project, visit ANALEMMA.

Written by Mateusz Radziwonowicz. Mateusz is a Biotechnologist from Poland, interested in astrophysics, quantum physics, light and its features.