THE ASTRONOMER Electronic Circular No 436 1990 Aug 10 10.29UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074 Telex: 94082518 Answerback: TAGUY Microlink: MAG60138 JANET:GMH @ UK.AC.CAM.ASTRONOMY.STARLINK or GUYH@UK.AC.SUSSEX.CLUSTER --------------------------------------------------------------------- PERIODIC COMET HALLEY (1986III) R.M.West, ESO, reports that CCD observations at r=12.5AU on 1990 Feb 21-24 with the Danish 1.5-m telescope at La Silla yield variations in Johnson V between 23.7 and 25.0. The mean value of 24.4 is 0.35mag brighter than expected from the nucleus alone. No coma is visible at the 29mag/arcsec2 level (1500 times less than the sky background emission!). Halley seems to have entered a long period of hibernation which is likely to last until mid-2061 when it again comes within about 5AU from the Sun and will again be awakened by the sunlight. ESO Information Bulletin SUPERNOVA 1990U IN NGC 7479 C. Pennypacker, S. Perlmutter and H. Marvin communicate: "The Berkeley Automated Supernova Search reports the discovery of a supernova 22" west and 54" south of the nucleus of NGC 7479 (R.A. = 23h02m26s, Decl. = +12d03'.1 (equinox 1950.0) and lying on a possible H II region. Images obtained on July 27.364, 27.365 and 27.408 UT show the object at mag 16 +/-0.5. The supernova was not present to limiting mag 17.5 (90-percent-confidence limit) on an image obtained on June 28." IAUC 5063 PERIODIC COMET HONDA-MRKOS-PAJDUSAKOVA (1990f) Ephemeris extension to E-424: 1990 ET R.A. (1950) Decl. Delta r m1 Aug. 17 6 42.75 +15 29.9 0.416 0.766 9.8 22 7 20.75 +16 05.2 27 7 51.89 +16 12.6 0.579 0.643 9.0 Sept. 1 8 18.94 +16 00.5 6 8 43.84 +15 31.4 0.778 0.559 8.4 11 9 07.75 +14 45.7 16 9 31.10 +13 44.1 0.995 0.546 8.7 21 9 53.77 +12 29.3 26 10 15.41 +11 05.3 1.203 0.609 10.1 Oct. 1 10 35.77 + 9 36.5 6 10 54.73 + 8 06.6 1.384 0.721 11.9 IAUC 5072 TA INDEX Denis Buczynski, Assistant E-Circulars Editor is now also available on JANET. Using 'MAIL' his address is: CBS%UK.AC.LANCS.CENT1::ESA123 Following the return of the Editor from Finland, all reports can again be sent to the addresses at the top of this circular, Guy M Hurst