Sorry, I was distracted by contemplated color measurements of all those distant background galaxies shining through the disk of NGC 4921. There is a catalogued quasar at z=0.24 which looks as if it might be the one (1259+281, SDSS J 130128.14+275106.6), although that ID depends on my having matched structure in NGC 4921 between the ACS image and Palomar survey to get the orientation right.


Looking at the caption - rats! They didn't get to finish the Cepheid search in this (practically the only) spiral in the Coma Cluster before loss of the ACS WFC. I hope they get to complete that with the repaired camera [always with the proviso that doing so does not interfere with scheduling observations of Hanny's Voorwerp, of course...]