LIGHTYEAR 2026
Step inside the Round Tower and explore a full year dedicated to light. From February and all through 2026, you can enjoy special exhibitions, concerts and family-friendly events – all celebrating the 350th anniversary of Ole Rømer’s discovery of the speed of light. The celebration of light will culminate when the Observatory at the top reopens later in the year with a beautifully restored dome and telescope.
Ole Rømer and the great discovery
The year 2026 marks the 350th anniversary of the publication of one of the most significant discoveries in the history of science. It all began in December 1676, when a French scientific journal shared remarkable news: the Danish scientist Ole Rømer had cracked one of the biggest mysteries of the era. By studying the movements of Jupiter’s moons, he had proved that light does not travel instantaneously – it has a measurable speed.
Ole Rømer was affiliated with the Round Tower both before and after his great discovery in Paris. When he returned to Copenhagen, he became head of the three university functions that were all gathered in the old Trinitatis Complex. A few of the observations that led to his discovery were likely also made from the Round Tower. Throughout 2026, the Round Tower will host four special exhibitions and a rich programme of music and events exploring the theme of light. You can also learn more about Ole Rømer and his discovery through lectures, guided tours and a year-round historical exhibition.
What’s On
A new light installation by the design studio Yoke will light up the tower platform – a work that allows us to sense light through scale, time, and space. The installation marks the beginning of “Lightyear 2026” and continues Ole Rømer’s curiosity about understanding what light truly is – not through measurement, but through experience.
This year’s program also features light concerts, cyanotype workshops and a winter holiday program for children including lantern walks through the dark tower.
The full event program will be announced in December.
What's on
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While the Light Hesitates
Light Installation, Winter BreakThe Viewing Platform06. Feb - 06. Apr -
Workshop: Paint with Light
For children, Winter BreakThe Library Hall09. Feb - 10. Feb -
Create Stunning Blue Images with Cyanotype
For children, Winter BreakThe Reading Room07. Feb -
Lantern Walk for Children
For children, Winter BreakThe Round Tower12. Feb -
Winter Light Bar
Special eventThe Viewing Platform28. Feb -
Toward the Light – Classical Concert with Michalak and Schermi
ConcertThe Library Hall26. Feb
EXHIBITION: AD LUCEM
6. FEB – 6. APR
“Lightyear 2026” opens with “Ad Lucem” (To the Light) – an artistic and scientific collaboration between artist Cecilia Ömalm and professor of astronomy Göran Östlin – a project that beautifully unites art and science in an exploration of how light from distant galaxies connects us across time and space.
Experience captivating, deep-blue photographic works created with cyanotype – a unique technique invented by astronomer John Herschel, where iron salts mixed to result in UV-sensitive solutions, and sunlight combine to form images in characteristic shades of blue.
Ömalm and Östlin recreate the light of the Universe using both historical glass plate negatives and modern digital image sensors. Each work is hand-printed, and when sunlight develops these celestial images, it becomes a poetic act – a rebirth of light from the same sky the telescopes once pointed toward.
“Ad Lucem” at the Round Tower marks the duo’s largest solo exhibition to date, featuring 40 works – including a new piece inspired by Ole Rømer’s groundbreaking measurements of the speed of light – presented in a design that mirrors the tower’s shape and evokes the atmosphere of an observatory.
EXHIBITION:
AFTERGLOW. CONVERSATIONS ON LIGHT
17. APR – 21. JUN
What connects art and astrophysics? In this exhibition, you will meet eight artists who, in dialogue with astrophysicists, explore the phenomenon of light. Both art and astronomy share a fascination with the speculative and the mysterious — and with the sense that behind the fog lies a clarity that reveals itself in fleeting glimpses. Science tests and confirms hypotheses, while art examines the world through sensory experiences that evoke reflection. Together, they can help us see the world in a new light and create new narratives about reality.
The exhibition invites you into a space where art gives form to astrophysical phenomena. Here you can experience works that are both visually captivating and thought-provoking — a meeting between scientific facts and aesthetic explorations of light, time, and cosmic spirituality.
The exhibition is created by the curatorial collective Perelin, Nattens Skov, founded by Veronica Rigét and Biba Fibiger.
EXHIBITION:
REFRACTIONS OF ICE
26. JUN – 20. SEP
In “Refractions of Ice”, art and science meet in a visual exploration of the deep ice. Under polarized light, the crystals of the ice emerge in surprising patterns, where the ice’s own poetic language—of colors, shapes, and movements—reveals traces of past climates and hints at transformations yet to come.
The exhibition presents macro-optical film recordings of ice crystals from millennia-old ice cores, extracted from three kilometers deep within the Greenland ice sheet. Through a scientific and visual study of the ice crystals’ microscopic movements and melting processes, the work invites the viewer into the deep narratives of the ice, where vibrant crystals become images of the planet’s mutability.
Video and sound translate ice-core research into a sensory experience, where the encounter between science and aesthetics creates a visual space for reflection on nature’s transformations and humanity’s place within them—in a time of climatic and existential shifts.
The work was created by Visual Science Studio in collaboration with researchers from the Centre for Ice and Climate at the Niels Bohr Institute, University of Copenhagen.
EXHIBITION: LIGHT ECHOES
2. OCT 2026 – 3. JAN 2027
It can be a challenge for researchers to create broad understanding of their discoveries, and this is where art can play an important role in communicating and visualizing them. In this exhibition, artists, curators, and astrophysicists explore how the relationship between light and time influences cosmic phenomena such as the expansion of the universe, the observation of distant galaxies, the explosion of massive stars, and the gravitational lensing effect — through four installations and a soundscape.
The title of the exhibition refers to the astronomical phenomenon known as a light echo, in which light from a distant stellar explosion, initially scattered in all directions, is later reflected by interstellar dust at another time and place. This reflection of the original light wave is perceived from Earth as a mirror image of the past. At the same time, the light echo serves as a metaphor for the artists’ work and for the boundless potential of collaboration across disciplines. By reflecting scientific discoveries through artistic expression, new ways of seeing and understanding the universe emerge.
The exhibition has been created and developed in close collaboration with the newly established ArtScience Program at the Niels Bohr Institute by Irene Campolmi, Head of the ArtScience Program.
Restoration of the Observatory dome and telescope
The skies have been observed from the Round Tower since it was completed in 1642, including during Ole Rømer’s own time here. This long tradition will take a brief pause in 2026, as “Lightyear 2026” overlaps with a six-month restoration of the nearly 100-year-old telescope and the dome that houses it.
The Observatory will reopen later in the year – renewed and ready for the next chapter. Once the telescope has been remounted on the outdoor platform and pointed towards the night sky, visitors will once again be able to explore the stars and planets – and that tiny hesitation of light.
