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01 magnitude, error to. 01 magnitude, class, bandpass, and a flag to tell how many entries there are for that object. GSC Classification Codes 0 Star 1 Galaxy 2 Blend 3 Non-star (can be galaxies, blended objects, defects, etc) 4 Unclassified 5 Artifact The multiple flag is used to flag the same object appearing on more than one plate. GSC Bandpass Codes 0 : J photographic IIIaJ + GG495 1 : V photographic IIaD + W12 2 : FGS 3 : B photoelectric 4 : V photoelectric 5 : R photographic IIIaF + RG630 6 : V495 photographic IIaD + GG495 7 : O photographic 103a0 + no filter GSC-ACT The purpose of the GSC-ACT project is to recalibrate the Hubble Guide Star Catalog (GSC), version 1. 1, using the ACT (Astrographic Catalog/Tycho.
A way to use the USNO ACT disk with Guide 6. 0 and Charon: On all Guide 7. 0 and some Guide 6. 0 CD-ROMs, the proper motion data for most Tycho stars has been replaced with proper motions from the USNO ACT (Astrographic Catalog/Tycho) dataset. This dataset improves the precision of proper motions about tenfold. The main cause of imprecision in Tycho is poor quality of the proper motion, so using ACT gives much better accuracy.