They are called anticrepuscular rays. Behind this tongue-twisting term lies a breathtaking play of light that the Sun can conjure up in the sky. A photo capturing these rays recently propelled Brno, along with its Špilberk Castle, onto the American space agency NASA’s website. It is an achievement many scientists only dream of. The photograph was taken by Pavel Gabzdyl, an astronomy popularizer from the Brno observatory.
The unique image was shot from the tower of St. Augustine’s Church and showcases the so-called anticrepuscular rays over Špilberk Castle. The photo was taken during the Festival of Planets, where the Brno observatory displays its inflatable celestial bodies. The photograph managed to capture the magical light effect that occurred when a large storm cloud momentarily obscured the Sun. Gabzdyl, who had climbed the church tower to photograph sci-fi enthusiasts gathered with their lightsabers from the legendary Star Wars saga, described the moment as pure chance.
Gabzdyl explained to Novinky that he took around a hundred photographs, but the stunning rays appeared in just one. This serendipitous shot was taken on the evening of July 11th, during the Festival of Planets. The image shows the interplay of light and shadow, an unpredictable and ephemeral spectacle, making it even more remarkable.
The NASA website explained the phenomenon: “bands known as anticrepuscular rays form over large clouds near the western horizon, casting long shadows through the atmosphere at sunset. Due to the camera’s perspective, the bands of light and shadow appear to converge towards the eastern (opposite) horizon at a point visible just above the castle on the hill.”
Gabzdyl, who specializes in lunar astronomy, works at the Brno Observatory and teaches at the Faculty of Science at Masaryk University in Brno. In 2013, the Czech Astronomical Society awarded him the Littera Astronomica Award for his contributions to popularizing astronomy. His work extends beyond photography; he is also an author and educator, continually inspiring interest in the cosmos.
Getting featured as NASA’s “Astronomical Picture of the Day” is a significant honor; to date, only sixteen photographers and scientists from the Czech Republic have achieved this. Among them is astrophotographer Petr Horálek from Silesian University in Opava, who has also been featured multiple times. The list includes mathematician Miloslav Druckmüller from Brno University of Technology, known for his team’s photographs of the solar corona taken worldwide.