And in regard to how GSC names themselves should be written: From the <<Dictionary of Nomenclature of Celestial Objects>> (Lortet, Borde, Ochsenbein, 1994, A&AS, 107, 193) (Last CDS update: 10-Jan-2002) ========================================================================= GSC = HSTGC (Guide Star Catalog) Write: <<GSC FFFFF-NNNNN>> .... If one uses the decimal to separate the region and serial numbers, please also use the necessary leading zeros, e.g. GSC 4822.0039. But the preferred usage is: GSC 04822-00039. See also: http://vizier.u-strasbg.fr/cgi-bin/Dic for additional details. \Brian