 In 1861 the observatory was moved to Østervold, where a new observatory was constructed on the old bastioned fortifications of the city, which had become outdated and were being disabandonned.The well-known Russian-German astronomer, Heinrich Louis d'Arrest, who had been appointed professor in astronomy at the university in 1857, was chosen to plan the new observatory.He used the observatory for his study of nebulas, in 1867 publishing an astronomical catalogue of 1,942 nebulas with 4,900 positions.