All the searching and mailing is starting to show result. Yesterday I received a high quality scan from a collector of postcards in Vienna of the sanatorium in Vorderbrühl where Teodor Scheimpflug died in 1911. Today I got a reply from the Technical Museum in Vienna that they have the 8-lens panoramic camera that Scheimpflug used for his experiments. I'm trying to get a good colour photo of the instrument. They also mailed an example of a photo taken with a earlier 3-lens camera.
Still no photo of the Sternwartestrasse 39 in Vienna, but I did get two good suggestions how to try to get one.