southern double stars (Richard Alfred Rossiter, 1886-1977) Ru - Jaroslav Ruprecht (open star clusters) RX — ROSAT observations S S - James South, 1785-1867 (double stars) Sa - Sanduleak (planetary nebulae) SA - Sandqvist (dark nebulae) (for example: Sandqvist 169 near Alpha Centauri, see APOD - Astronomy Picture Of the Day, April 13, 2019) SACS — Second Astrolabe Catalogue of Santiago Saloranta - Jaakko Saloranta (telescopic asterisms) SAO — Smithsonian Astrophysical Observatory Star Catalog Saurer - (for example: the open star cluster Saurer 1 at 7:18:18 / +1°53'12") SaWe - Sanduleak-Weinberger (planetary nebulae) SAX - Satellite per Astronomia a raggi X (Beppo SAX satellite) SC — Slough catalogue ("Observations of Nebulae and Clusters of Stars, made at Slough, with a Twenty-Feet Reflector, between the years 1825 and 1833" by John Herschel; 2306 entries) Schb - J.M.Schaeberle (double stars) Schj - H.C.F.C.Schjellerup (double stars) Schoenberg - (for example: Schoenberg 205-6 at 6:37.1 / +10°21') Schuster - (for example: open star cluster Schuster 1 at 10:04:39 / -55:51:29) SCM — Schwarz, Corradi, Melnick catalogue. Scott - J.L.Scott (double stars) SCR — SuperCOSMOS-RECONS SDSS — Sloan Digital Sky Survey SDSSp — Sloan Digital Sky Survey, provisory 1SDSS — Sloan Digital Sky Survey, 1st release 2SDSS — reserved by the Sloan Digital Sky Survey for future release. The name is reserved to the IAU, but does not exist yet. 3SDSS — reserved by the Sloan Digital Sky Survey for future release. The name is reserved to the IAU, but does not exist yet. Se - Father Angelo Secchi (double stars) Se - Sersic (selected list of peculiar galaxies and groups of galaxies) See - T.J.J.See (Thomas Jefferson Jackson See, 1866-1962) (double stars) (related to the 'Lambda' catalogue which is mentioned in T.W.Webb's Celestial Objects for Common Telescopes, Volume 2: The Stars, pages 285-319: Index of Double Stars, Epoch 2000). SEGUE - Sloan Extension for Galactic Understanding and Exploration (for example: galaxies Segue 1 in Leo, Segue 2 in Aries, and Segue 3 in Pegasus) Sei - J.Scheiner (double stars) SGR - Soft Gamma Repeater Sh — Sharpless catalog (Sh 1 (1953) & Sh 2(1959)) Sh - Sher (open star clusters) (for example: Sher 1 at 11:01:04 / -60:14:00) S, h - James South / John Herschel (joint 1824 catalogue of double stars) Shk - Romela Karapet Shakhbazian (compact groups of galaxies) (for example: Shakhbazian 1 (the 'Russian Cluster') in Ursa Major, at 10:54.8 /