Posted in Astronomy Resources
Tags: Arp, caldwell, catalogs, collinder, double stars, galaxies, Herschel, IIC, LDN, logbooks, Lund, Lynds, Messier, messier marathon, Minkowski, NGC, Perek-Kohoutek, PK, planetary nebulae, Sh, Sharpless, UGC, Uppsala
Posted in Deep Sky Objects, IC 1296, Index Catalog, M57, Messier Catalog, New General Catalog, NGC 6720
Tags: DSO, M57, NGC 6720, Paul Rix, planetary nebulae, Ring Nebula