------------------------------------------------------------------- THE ASTRONOMER Electronic Circular No 2656 2010 Jly 09 14.38UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England.Telephone/FAX(01256)471074Int:+441256471074 INTERNET: GUY@TAHQ.DEMON.CO.UK Backup: gmh@wdcc1.bnsc.rl.ac.uk WORLD WIDE WEB http://www.theastronomer.org ------------------------------------------------------------------- CH CYGNI J. L. Sokoloski et. al., (Columbia)report on The Astronomer's Telegram 2707 that observations of CH Cyg with the Kepler satellite and the 0.6-m telescope of the National Astronomical Observatory Rozhen (Bulgaria) reveal that the minute-time-scale optical flickering that CH Cyg typically produces has disappeared. Kepler observations beginning 2009 Dec 17, show flickering with approximate peak-to-peak amplitude of several mmag (on a time scale of less than an hour, in the Kepler bandpass) between 2009 Dec 17-27. During this time, the overall optical brightness gradually increased. During roughly the following 20 days, the overall optical flux decreased and the fractional amplitude of the rapid optical flickering declined. Between 2010 mid-January and mid-March rapid optical flickering was undetectable with Kepler. CCD observations from the 0.6-m telescope in Rozhen during three nights in May did not show any flickering above 0.04 mag in U, B, and V filters. In the past, the disappearance of rapid optical flickering has been attributed to either an eclipse of the accreting white dwarf, a change in the structure of the accretion disk or the activity of a magnetic propeller. SUPERNOVA 2010dm IN ANONYMOUS GALAXY Discovery by ROTSE collaboration of a possible supernova (CBET 2297): SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010dm May 23.28 12 11 33.31 +47 16 29.1 18.2 0.1"W, 0.5"N A finding chart for the object can be found at website URL http://www.rotse.net/rsvp/j121133.3+471629/j121133.3+471629.jpg J Caldwell reports a spectrum of May 28 shows it to be type-Ia, then a few days before maximum. SUPERNOVA 2010dn IN NGC 3184 Discovery by Koichi Itagaki of a possible supernova (CBET 2299): SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010dn May 31.52 10 18 19.89 +41 26 28.8 17.5 33 "E, 61 "N Itagaki's discovery image has been posted at the following website URL: http://www.k-itagaki.jp/images/psn3184.jpg SUPERNOVA 2010do IN NGC 5374 Discovery by Berto Monard of a possible supernova (CBET 2301): SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010do Jun 1.78 13 57 28.11 +06 05 48.5 17.2 23 "W, 2 "S A. Narla, S. B. Cenko, W. Li, and A. V. Filippenko, University of California, report the independent LOSS discovery on June 2.25 at magnitude 17.6. P Challis reports it is a type-Ic supernova near maximum light according to a spectrum of June 7 Guy Hurst, using the Sierra Stars 0.61-m Cassegrain robotic telescope has obtained V photometry: June 17.21UT, 16.5V; 20.21, 16.2; July 2.21, 17.0. These magnitudes were obtained from 30 second exposures. SUPERNOVA 2010dp IN ANONYMOUS GALAXY Discovery by CRTS of a possible supernova (CBET 2302): SN 2010 UT R.A. (2000.0) Decl. Mag. Offset 2010dp May 18.42 09 32 03.70 -05 53 38.1 16.7 1.8"S A spectrogram obtained with the SMARTS 1.5-m telescope on June 1.97shows it to be similar to the type-Ia supernova 1999aa at one month past maximum light Guy M Hurst