Circular No. 4440 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Postal Address: Central Bureau for Astronomical Telegrams Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444 COMET RUDENKO (1987u) A new comet has been discovered by Michael Rudenko, Amherst, Massachusetts. The following observations are available: 1987 UT R.A. (1950) Decl. m1 Observer Aug. 21.111 14 08.0 +34 00 9.5: Rudenko 21.20 14 08.1 +33 59 Morris 21.24 14 08.0 +33 59 9.9 " M. Rudenko (Amherst, MA). 0.15-m refractor. Object diffuse with slight condensation, coma diameter 2'-3'. C. S. Morris (Whitaker Peak, CA). 0.26-m reflector. No condensation or tail. Motion definitely detected. SUPERNOVA 1987A IN THE LARGE MAGELLANIC CLOUD M. Karovska, P. Nisensen, C. Papaliolios and C. Standley, Center for Astrophysics, report: "Follow-up observations were carried out during May 30-June 2 with the purpose of detecting the second bright source (IAUC 4382) using our speckle system and the CTIO 4-m telescope. Data were recorded in 10-nm bandpasses at H alpha and seven other optical wavelengths in the range 400-775 nm. Conditions were fairly good (2"-3" seeing) on two of the four nights. Careful analysis of these data has not provided a certain detection of the second source above the background noise. For a certain detection the magnitude difference at the time of these observations would have to be less than about 4. SN 1987A had brightened from mv about 4.1 at the time of our original observation (Mar. 23) to mv about 3.1 for these observations, so if the second source remained at its originally detected brightness the magnitude difference between it and the supernova would have been about 3.7. Data from additional observations carried out in early July using the same telescope and equipment are still being reduced. The positions of the second source relative to the supernova were remeasured in the reconstructions from data taken on Mar. 23 and Apr. 2. To the limits of accuracy of the process (0".015) there was no detectable change in the separation. Better accuracy in centroid determination might have been possible if the supernova were at a greater zenith angle, where atmospheric dispersion would have less of an effect." 1987 August 21 (4440) Brian G. Marsden
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