The Observatory

The Round Tower is the oldest functioning observatory building in Europe. King Christian IV erected the tower to enable astronomers from the University of Copenhagen to gaze at the stars far above the lights and the smoke of the city. For centuries, it was the centre of Danish astronomy and the point of departure for meteorological observations and surveying. The Observatory at the top has undergone several changes throughout history. The present Observatory dates from 1929. The same year the refracting telescope arrived, allowing a magnification between 80 and 450 times. During the winter months, the Observatory is normally manned Tuesday and Wednesday evenings but you are always welcome to look inside and let your thoughts wander across the Universe.

The observatory will be restored in 2025/2026 and will close temporarily during this period.

Follow the project and find more information here.

The Observatory through time

The Round Tower is Europe’s oldest working observatory building. However, the Observatory at the top has changed appearance several times throughout its history. Discover the story of the Round Tower Observatory here

Tycho Brahe Was Not Here

Tycho Brahe has never set foot in the Round Tower, which was not finished until long after the world-famous Danish astronomer had died in exile in Prague. Yet there is a direct line from Tycho Brahe to the Observatory at the top of the tower.

Almanac

For nearly 200 years, the Round Tower figured on the front cover of the University of Copenhagen's almanac as a as a token of the university vouching for the authenticity of the content. But you should not believe everything you read.

The bombardment of Copenhagen 1807. Museum of Copenhagen

Rocket Science Seen from the Round Tower

The British bombardment of Copenhagen in 1807 was not just a catastrophe for the city. The rain of bombs, grenades and rockets also led to what has been called the world's first example of rocket-based astronomy - with the Round Tower in an important role.

The Elements of Wind and Weather

From 1751 onwards, astronomers made daily systematic observations of the weather at the top of the Round Tower. They did it for the first time in Denmark and had a very specific purpose. For what if you could predict rain, snow, lightning and thunder for years to come?

The Observatory with the Greenlandic flag

The Universe in Greenlandic

The Danish Astronomer G. F. Ursin disliked the Greenlanders thinking of the Sun as a Greenlandic woman and the Moon as a Greenlandic man. But he himself had no problems imagining life in space.

The Observatory

The Observatory

The Observatory through time

Tycho Brahe Was Not Here

Almanac

Rocket Science Seen from the Round Tower

The Elements of Wind and Weather

The Universe in Greenlandic

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