Electronic Telegram No. 2751 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2011ds = PSN J20022093-2013134 S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. L. Prieto, Carnegie Observatories; M. Catelan, Pontificia Universidad Catolica de Chile; R. H. McNaught and G. Garradd, Australian National University; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona; and E. Christensen, Gemini Observatory, report the discovery of an apparent supernova in public images from the Catalina Sky Survey; it was confirmed in images obtained with the Siding Spring Survey (SSS). SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011ds May 13.42 20 02 20.93 -20 13 13.4 16.6 6" W, 17" N The variable was designated PSN J20022093-2013134 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011ds based on the spectroscopic confirmation that is detailed below. Further magnitudes for 2011ds: Apr. 11.74 [19.0 (SSS); May 14.69, 16.6 (SSS); 15.721, 16.6 (Joseph Brimacombe, Coral Towers Observatory, Cairns, Australia, 30-cm telescope + STL6K camera + red filter; position end figures 20s.92, 12".8). Brimacombe's image is posted at URL http://www.flickr.com/photos/43846774@N02/5724709574/. S. Valenti and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a larger collaboration, report that a low-signal-to-noise spectrogram (range 330-750 nm; resolution 1.5 nm) of PSN J20022093-2013134 = SN 2011ds, obtained on June 26.43 UT with the European Southern Observatory's New Technology Telescope (+ EFOSC2), is consistent with that of a type-II supernova. The spectrum indeed shows strong hydrogen H-alpha at 669.1 nm, mainly in emission with a full-width-at-half-maximum of about 7400 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 June 28 (CBET 2751) Daniel W. E. Green