http://www.spitzer.caltech.edu/Media/releases/ssc2006-08/" The Spitzer Telescope views Stephan's Quintent. I remember reading a writeup Halton Arp had about this a time back (please, this is not the place for "shots" against him), that he thought the bottom left galaxy was actually a member of the group, but had a discordant redshift .. and it went against conventional wisdom. Here's a couple of quotes in the article, with my emphasis: It appears to me the "green arc" is in front of the galaxy that is supposed to be a foreground object. I suppose since it is of a different wavelength of light, it could bleed through a foreground galaxy that didn't emit very much of that wavelength .. but it all looks fishy to me! I guess it could be that the "green arc" they are talking about is not the large green filament in the center of the picture (and that would be an even closer object, perhaps in our galaxy) but the small green-to-red arc in the interacting galaxy to the right that makes a smilely face with the 2 concentrated light objects above it. What am I missing here!?!