==The Albrecht Dürer House == 

 Dürer was four years old when Regiomontanus left Nürnberg so he could not have bought a house from him. The house you are referring to is the Albrecht Dürer House in Nürnberg. It was first bought by Dürer in 1509, thirty three years after Regiomontanus' death. The astronomical shelf in the one attic window was installed by Bernard Walther when he bought the house in 1501, twenty five years after Regiomontanus' death. Walther died in 1504. What is true, is that Dürer, who was indeed interested in astronomy, bought the house because it had belonged to Walther.