Circular No. 5420 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. Telephone 617-495-7244/7440/7444 (for emergency use only) TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505 MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN COMET MUELLER (1991h1) On 1991 Dec. 18 Jean Mueller reported her discovery of a probable comet on a single exposure on Dec. 13 by C. Brewer, D. Mendenhall and herself with the 1.2-m Oschin telescope in the course of Palomar Sky Survey II. The object was diffuse with a possible faint tail to the southwest. The discovery has now been confirmed on a film obtained on Dec. 31 by E. M. Shoemaker, C. S. Shoemaker and D. H. Levy with the 0.46-m Schmidt. The following measurements are all by Mueller: 1991 UT R.A. (2000) Decl. m1 Observer Dec. 13.48264 9 38 56.16 +42 31 23.9 17.5 Mueller 13.52778 9 38 53.58 +42 31 53.0 " 31.35486 8 58 02.50 +47 38 09.3 16 Shoemaker 31.39444 8 57 52.55 +47 38 58.2 " SUPERNOVA 1991bj IN IC 344 C. Pollas, Observatoire de la Cote d'Azur, reports his discovery of a supernova of mag 18.8 in IC 344 (mag 15) on exposures with the 0.9-m Schmidt telescope on 1991 Dec. 30.9 and 31.9 UT. The object is at R.A. = 3h39m01s.27, Decl. = -4d49'23".5 (equinox 1950.0), the offset from the nucleus being 14".0 east, 7".6 north. A nearby star of mag 16 is located at R.A. = 3h38m59s.67, Decl. = -4d49'14".8, and one of mag 17 is at end figures 58.81, 15.2. A. V. Filippenko, University of California at Berkeley, reports that inspection of an uncalibrated CCD spectrum (range 410-730 nm, resolution 1 nm) obtained on 1992 Jan. 1 UT with the Shane 3-m reflector at Lick Observatory shows that the supernova is probably of type Ia about one month past maximum brightness. E. Cappellaro and M. Della Valle, European Southern Observatory, report that a spectrum obtained with NTT + EMMI (range 400-1000 nm, resolution about 2 nm) on Jan. 1.06 UT shows the object to be a type Ia SN about one month after maximum. Strong emissions are measured at 506, 562, 575, 667, 796 and 877 nm. The galaxy redshift determined from the emission of the underlying H II region is 5450 km/s. From a CCD frame the supernova was estimated at V = 18.3. 1992 January 1 Brian G. Marsden