[Heliostat and] Window for Moving Light

a closeup of ornately carved gothic finials on a wooden choir wall that are painted what seems to be white, with the larger space of the cathedral nave extending into the background, but the main feature of this photo is this architecture bathed, from bottom to top, in red, orange, yellow, and blue light, pouring in through the handblown glass window installation by olafur eliasson. at the st nicholas cathedral in greifswald germany.
Olafur Eliasson, Window for Moving Light, 2024, stained glass and heliostat, St Nicholas Cathedral, Greifswald, Germany, image: Jens Ziehe via olafureliasson.net

Olafur Eliasson has created a work of light and handblown glass for the east windows of St. Nicholas’s Cathedral in Greifswald, a Hanseatic city near the Baltic coast of Germany, which was the birthplace of Caspar David Friedrich. Originally built in the 14th century, the church was remade in the 19th century with woodwork by Friedrich’s brother, Christian Adolph, including the elaborate Gothic choir wall which closes off the windows from the rest of the interior.

The work is titled, Fenster für bewegtes Licht (Window for Moving Light). Because the east window only catches the morning sun for a small portion of the day—and that portion is limited further by the building directly across the street—Eliasson installed a heliostat, a mirror that tracks the movement of the sun, on that building to reflect afternoon sun into the morning window.

the east facade of a gothic brick cathedral in greifswald germany is dark against the deep blue sky of late afternoon or early evening, flanked by shadowy trees. the three tall, thin gothic windows with white tracery glow in a rainbow spectrum, dark red at the bottom to deep blue at the top, so mostly oranges and yellows in the middle, an installation by olafur eliasson
Olafur Eliasson, Window for Moving Light, 2024, exterior view of the east facade of St Nicholas’s Cathedral, Greifswald, photo: Jens Ziehe via olafureliasson.net

When I first discussed with Olafur an idea for a work that involved a heliostat reflecting light into our north-facing apartment in New York, in 2003, [while I had the concept, he already knew what a heliostat was and where to get one], I imagined sunlight that doesn’t move around the room would become very unsettling.

So it is buck wild to see a similar setup behind the altar of a church, where it is intended to encourage “pause and reflection – aspects central to both the Romanticism of Caspar David Friedrich and Protestant spirituality.”

Or does an beam of sunlight coming at an uncharacteristic time into a building oriented so specifically have a different effect? The afternoon sun from the east can become a metaphor, or it can encourage pause and reflection on the human, artistic intervention that produced it, drawing viewers’ attention to the world outside the church.

Fenster für bewegtes Licht (Window for Moving Light), 2024 [olafureliasson.net]