Krüger sent an application on 4 December describing his previous work, publications and instruments and a suggestion for a deal contingent on 3 conditions:[2] The city council discussed the matter on 25 February 1909 with a positive outcome and on 3 June it was decided to build the observatory and accept the 3 conditions.

[2] The Ole Rømer Observatory was listed in January 2006 by the Danish Heritage Agency, almost 100 years after it was completed in 1911.

The reasons cited was the uniqueness of the architecture which unites the arts and crafts movement of the time with a functionalist impression and that it was designed by Anton Rosen, a prolific 20th-century Danish architect.

[2] During the construction phase of the observatory there was a heated debate in newspapers, among others Århus Stiftstidende, regarding Friedrich Krügers intentions.

[3] Krüger was frequently accused of being a spy which became more of an issue after his son joined the German army during World War I.

[4] The observatory building consists of a central house with a hall, office, workshop and classroom and two rotating cupolas for telescopes adjoining its sides.

The entire building is oriented according to the four corners of the world, with the movable zink clad observing cupolas north and east of the central room.

The outside architecture displays the arts and crafts style with a base of fieldstone in two sizes, low plastered walls and a tiled mansard-like roof.