A rich, nearby galaxy cluster in Sagittarius

The existence of a probable rich cluster, or a set of clusters in Sagittarius, seen through an extinction window in the direction of the Galactic bulge, is reported. In particular, redshifts are presented for 21 galaxies found among the objects originally identified by Terzan et al. (1978). It is suggested that the Sagittarius cluster is an entity separate from the previously discovered Ophiuchus cluster but that the two may be physically associated in a larger structure. This putative Sagittarius- Ophiuchus supercluster may be an important factor in the local supergalactic dynamics, possibly even more massive than the Coma-A1367 system, which is roughly the same distance. (V.L.)