Circular No. 4809 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 OCCULTATION OF 28 SAGITTARII BY TITAN Additional reported timings (cf. IAUC 4801, 4803, etc.): Observer t1 t2 central t3 t4 flash Arlot 41 55 Lecacheux 42 10 Shanklin 39 13 40 32 41 47 43 46 Stapleton 39 16.3 39 24 41 59 44 33.8 45 27 J. E. Arlot, W. Thuillot, F. Roques, F. Sevres (Paris-Meudon). 1-m and 0.6-m telescopes. Communicated by B. Sicardy. Half- light (half-intensity) times for the star's disappearance and reappearance are 39m24s and 44m28s; 28 Sgr was detected continuously until the central flash, a double-peaked feature with maxima at 41m55s and 41m58s. At both Meudon and Pic du Midi, the intensity of the flash is strongly wavelength-dependent, decreasing from the near-infrared to the blue, and the lightcurves are asymmetric with respect to the middle of the occultation. J. Lecacheux, B. Sicardy, F. Colas, J. L. Vidal, C. Buil, A. Klotz, E. Thouvenot, J. Bourgeois (Pic du Midi). 2-m, 1-m, 0.6-m, and 0.25-m telescopes. Half-intensity times for disappearance and reappearance are 39m35s and 44m57s; 28 Sgr was detected continuously until the central flash, a double-peaked feature with maxima at 41m55s and 41m58s. J. D. Shanklin (U. of Cambridge Observatories). 0.20-m Thorrowgood refractor (+ photometer); noisy signal. Central peak lasted from 41m47s to 42m23s. Half of maximum intensity occurred at 39m24s and 44m45s. J. R. Stapleton (St. Andrews University Observatory). Long. = -2 49'48.0, Lat. = +56 20'12.0, h about 40m. 0.10-m reflector. Seeing moderate to poor. Turbulence of 28 Sgr increased at 37m30s. Central flash lasted 1-2 s. SUPERNOVA 1989M IN NGC 4579 A. Cassatella reports two corrigenda concerning the item on IAUC 4808: (1) the second date should read July 8.84 (instead of July 7.84; lines 4, 8, and 12); (2) on line 9, for 0.184 and 0.173 erg cm-2 s-1 nm-1 read 0.184 and 0.173 x 10E-14 erg cm-2 s-1 nm-1. Visual magnitude estimates: July 7.21 UT, 12.0 (A. Hale, Las Cruces, NM); 9.14, 12.2 (J. Griese, Stamford, CT); 9.14, 12.2 (C. Scovil, Stamford, CT); 10.10, 12.1 (P. Sventek, Houston, TX). 1989 July 12 (4809) Daniel W. E. Green
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