See mailing list GSC1.2 The HST Guide Star Catalog, Version 1.2 (Lasker+ 1996) This is an excerpt of the GSC1.2. This version was re-reduced with PPM catalogue; see more details about the GSC catalogues at http://www-gsss.stsci.edu/gsc/gsc.html . gsc.outOutput from GSC1.2 Server Default result of GSC1.2 Server around a target _r Distance from target NGC40 GSC-Id Unique object id The GSC-Id is made of 10 digits, the first 5 representing the place number, and the last 5 the object number on the plate. RA(J2000) Right ascension in J2000, epoch of plate Dec(J2000) Declination in J2000, epoch of plate PosErr Mean error on position Pmag photographic magnitude (see n_Pmag) e_Pmag Mean error on photographic magnitude Class Class of object (0=star; 3=non-stellar)