101 Must-See Cosmic Objects: Stephan’s Quintet

Stephan’s Quintet, one of the first science targets of the James Webb Space Telescope, sits just 0.5° southwest of NGC 7331, making it one of the easiest tight groups to find. Halton C. Arp listed this compact group as Arp 319 in his 1966 Atlas of Peculiar Galaxies. Later, he used NGC 7320’s anomalous redshift — much lower than the others’ in the group, indicating it is much closer — to question the validity of redshift as a reliable measure of distance. But Hub