Notes:
The picture is of the Abell galaxy cluster A2218. This cluster is a very massive lens. Light from galaxies located behind the cluster is being bent around the cluster. The images produced are not full rings. This is because of the geometry of the system. Here, only only parts of rings are seen, these are called Arcs.
For a better reproduction of the picture and more information see:http://antwrp.gsfc.nasa.gov/apod/ap011007.html