Group of galaxies. Hubble Space Telescope (HST) image of the group of galaxies known as Hickson Compact Group 87 (HCG 87). The four galaxies seen here are: the large, edge-on spiral HCG 87a (lower centre), the bright elliptical galaxy HCG 87b (lower right), the spiral HCG 87c (upper left) and the smaller spiral HCG 87d (lower centre). HCG 87d is more distant than the other galaxies and is not thought to be part of the group. The other galaxies are linked by mutual gravitational attraction, which has distorted their shapes. The cluster lies about 400 million light years from Earth in the constellation Capricornus.