It is both nearby and bright; but it is difficult to observe because it is in the Zone of Avoidance. This is a region near the plane of the Milky Way, which obscures our view. The cluster is hidden by interstellar dust at optical wavelengths. Its mass is estimated to be on the order of 1015 solar masses.
- ESO Press Photos 46a-j/99
- The Norma Cluster on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- Galaxy cluster has two 'tails' to tell. NASA Image of the Day, January 22, 2010.
- "Norma Cluster". NASA/IPAC Extragalactic Database (NED). http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Norma+Cluster. Retrieved 2006-10-22.
- R. C. Kraan-Korteweg, in Lecture Notes in Physics 556, edited by D. Pageand J.G. Hirsch, p301 (Springer, Berlin, 2000).
- H. Boehringer et al., Astrophys. J. 467, 168 (1996)., R. C. Kraan-Korteweg et al., Nature 379, 519 (1996).