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dwarf nova

Special Notice #303: VLBA and e-MERLIN observations of SS Cyg underway

October 31, 2012:  The cataclysmic variable SS Cyg is beginning to decline from what appears to be a narrow outburst, and was at visual magnitude 9.1 on 2012 October 30, according to observations in the AAVSO International Database.

Alert Notice 459: Monitoring of RU Peg requested for Swift observations

6 June 2012: Dr. Koji Mukai (Universities Space Research Association/NASA Goddard Space Flight Center) has requested AAVSO observers' assistance in monitoring the SS Cyg-type dwarf nova RU Peg in support of target-of-opportunity observations with the NASA Swift satellite during an outburst.

His observations will be targeted during the rise to outburst and during late decline from outburst. Thus, your prompt notification to AAVSO Headquarters of activity in RU Peg will be crucial to the success of this campaign.

Special Notice #261: Outburst of the UGWZ Candidate BW Scl

October 21, 2011: The short period cataclysmic variable BW Scl appears to be in outburst. The object was detected in outburst at m(vis)=9.6 by M. Linnolt on 2011 October 21.3146 (JD 2455855.8146), and confirmed by A. Plummer at m(vis)=9.4 on October 21.3424.  Observations of this object are encouraged.  The object has conflicting classifications in astronomical literature, but is probably a WZ Sge-type dwarf nova rather than a novalike variable.

BW Scl is located at the following (J2000) coordinates:

Special Notice #245: Outburst of SV Ari

August 2, 2011:  SV Ari, a suspected WZ Sge star, has gone into outburst.  Rod Stubbings posted a 15.0 magnitude estimate on 110802.788 that has been confirmed by Gianluca Masi.  Gary Poyner says:

"Discovered by M & G Wolf on Heidelberg plates taken in November 1905 at mag 12.0p.  Kimpel & Jansch reported a possible sighting in September 1943, but this was not confirmed.  Nothing has been seen since."

Special Notice #239: Dwarf Nova in Pegasus (PNV J21095047+1348396)

May 31, 2011: IAU Central Bureau for Astronomical Telegrams Electronic Telegram CBET 2731 (Daniel W. E. Green, ed.) announces the discovery by K. Itagaki, Yamagata, Japan, of a dwarf nova in Pegasus (reported by H. Yamaoka, Kyushu University, Japan) on 2011 May 24.672 UT at unfiltered CCD magnitude ~11.5. Spectroscopy by Akira Arai, Koyama Astronomical Observatory, Kyoto Sangyo University, Japan, on 2011 May 25.67 UT, and by D. D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada, M. L.

Special Notice #233: Bright outburst of the cataclysmic variable SDSS J133941.11+484727.5

February 7, 2011: The star SDSS J133941.11+484727.5 has been reported in outburst by Jeremy Shears (Bunbury, UK).  Shears reports this star at magnitude 10.4 on 2011 February 7.919 (JD 2455600.419).  This is approximately 7 magnitudes above quiescence, which suggests a superoutburst of an SU UMa star or a WZ Sge-like outburst.  Gary Poyner (Birmingham, UK) confirms this outburst, estimating the star at 10.5 on February 7.959 (2455600.459).

Special Notice #221: Infrequent Outburst of the SU UMa Variable HT Cas

November 2, 2010: As reported by Tim Parson (Circle Pines, Minnesota, USA) and confirmed by Pavol Dubovsky (Kolonica, Slovakia), the infrequently-outbursting dwarf nova HT Cas is in outburst.  Parson observed HT Cas in outburst at m(vis)=12.9 on JD 2455502.93 (2010 November 2.43), and the outburst was confirmed by Dubovsky at m(vis)=12.4 on JD 2455503.3 (2010 November 2.8).  The last confirmed well-observed outburst of this star occurred on 2008 January 10.  Observations of this variable are strongly encouraged at this time.  Both visual and CCD observations are en

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