After speaking with Harold Corwin about an article in the Webb DSO he informs me that the preferred designation for Abell galaxy clusters is no longer AGC but ACO (Abell Corwin, Olowin) and that the AGC designation is now being used more and more for galaxies in an Areceibo survey. This is obviously a major change from the amateur point of view as despite the fact that various books and software still use the AGC designation I guess we may need to change. The number remain the same just the prefix changes. The same applies to the objects in the supplemental catalogue. They should be ACOS not AGCS.

regards

Owen