Electronic Telegram No. 1958 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2009jh Further to CBET 1956, A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; M. Catelan, Pontificia Universidad Catolica de Chile; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona; and E. Christensen, Gemini Observatory, report the CRTS discovery of a supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2009 UT R.A. (2000.0) Decl. Mag. Offset 2009jh Aug. 2.17 14 49 10.09 +29 25 10.4 18.9 7".8 W, 0".1 S The object was classified as a possible supernova and placed on public webpages on Aug. 2. Follow-up observations of 2009jh were made with the Palomar 1.5-m telescope using Gunn filters on Aug. 3.18 UT, yielding these magnitudes: g = 19.57, r = 19.51, and i = 20.06. Further CSS magnitudes for 2009jh: June 17.21 UT, [20.8; Aug. 29.15, 19.5. The object was independently discovered by Quimby et al. ("Palomar Transient Factory") on Aug. 11 (see http://lanl.arxiv.org/abs/0910.0059, where the object is noted as PTF09cwl), citing position end figures 10s.08, 11".4, who also obtained spectroscopic confirmation -- showing this to be a very luminous supernova at z = 0.349, most resembling spectra of SN 2005ap, suggesting that the outburst is due to pulsational electron-positron pair-instability. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 October 2 (CBET 1958) Daniel W. E. Green