After the fire of 1827, the only university in Finland, Turku Academy, was transplanted into the new capital, Helsinki. This was a period of lively research in the field of astronomical observations and designing a new observatory became topical.

The Helsinki Observatory was designed according to the wishes of the newly appointed professor Argelander, who was very well informed of the quick advances in the field, as well as of novel equipment. The site on the high rock hill of Ullanlinna, south of the town centre, was chosen by Argelander in November 1827, only some months after the Turku fire. Already in 1831, the instruments of Turku were packed into boxes and taken to Helsinki.

Technically and structurally the new observatory was notably more sophisticated than its predecessor in Turku. The structural foundations for the instruments were independent and not in contact with the foundations of the building or the floor joists, thus eliminating possible structural vibration that might interfere with the astronomical observation.

In 1829, the design was presented to the university consistory, followed by a letter from architect Engel in which he underlined three leading principles for the design:

 1. Because of the prominent site, the building was to be beautiful, so as to add to the beauty of the town.

 2. The scientific heart of the building, the meridian hall, was to be situated in the western part of the building, facing the so far unbuilt area for an unobstructed view and a fixed landmark.

 3. The apartments for the professor, his assistants and the janitor were to be placed within the observatory building. This, Engel explained, would profit not only rational comfort but also architectural beauty and integrity.

It is clear that the observatory building served the science of astronomy but to Engel it also played an important part in the art of town planning: the building is remarkably long and it was placed so that its long facade faced town, as a focal point, at the end of Unioninkatu street. On top of the hill, the building appeared bigger than its functional volume.

Today the observatory is hidden amidst lush lime trees and apartment buildings surrounding the once barren rock hill. The observatory was in scientific and academic use until 2010. Recently the building was restored to house an astronomical visitor centre, which is part of the Helsinki University Museum.

text: Kati Winterhalter