This tab allows you to specify all options pertaining to deep sky objects. In particular, it lets you select the current deep sky database: the catalogue of deep sky objects RNGC and NGC2000, the Revised New General Catalogue and Index Catalogue, the Saguaro Astronomy Club (SAC) catalogue, the Catalogue of Principal Galaxies (PGC 2003) and the BT-Atlas. To get information about one of the components in this tab, left click on it with the mouse in the image below: