 Sikorski searched the area nearby with instruments such as ground-penetrating radar in an effort to find Copernicus’ observatory "pavimentum", which was believed to have been nearby, but did not find it.Sikorski was aided in the search by the notebook of Elias Olsen, who was sent by Tycho Brahe to Frombork in 1584 to use the still-extant "pavimentum" to obtain astronomic observations for comparison with those of Copernicus.the "pavimentum" has still not been located.