The objective of the software described in this note is to use the Space Telescope Guide Star Catalogue (hereafter GSC) to locate guide stars suitable for the La Palma Telescopes. The GSC provides a large number of stars with (fairly) accurately-known positions. It will generally contain several stars in any of the guiding fields for all except the most perverse target positions (e.g. in dark clouds). The only exception is the WHT Nasmyth focus (through the derotation optics), where the field is too small to guarantee that a suitable star will be found. The software, therefore, accesses the GSC, finds suitable guide stars for a given position and telescope configuration and outputs their positions in a form suitable for the telescope, A&G and autoguider control software.