Observations of all the NGC and IC objects
Steve Gottlieb's NGC Notes
http://adventuresindeepspace.com/steve.ngc.htm
Data on all the NGC and IC objects by Dr. Wolfgang Steinicke
http://www.klima-luft.de/steinicke/ngcic/ngcic_e.htm
All the NGC objects from Dr. Harold Corwin and
others
http://ngcicproject.observers.org/NGC/