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cataclysmic variable

Alert Notice 591: GW Lib observations requested in support of K2 and HST observations

August 7, 2017: Dr. Boris Gaensicke (Warwick University) has requested our help in monitoring the pulsating white dwarf-containing cataclysmic variable GW Lib in preparation for and support of K2 (Kepler's Second Light) and Hubble Space Telescope (HST) observations scheduled for August to November 2017 and August and September 2017, respectively.

K2 will be observing GW Lib non-stop 2017 Aug 23 20:00:00 to 2017 Nov 19 23:00:00 UTC.

Alert Notice 588: Long-term CCD monitoring of ER UMa-type variable DDE 48 in Vulpecula

July 21, 2017: The following request for AAVSO assistance has been received from Denis Denisenko (Sternberg Astronomical Institute, Moscow State University) to help characterize "...the cataclysmic variable DDE 48 in Vulpecula. This CV belongs to the rare ER UMa subtype of dwarf novae, with only 6 other stars in VSX being classified as UGER. According to 2016-2017 observations by Nikolay Mishevskiy (MNIC) and Denis Denisenko (DDE), this variable is very active, with superoutbursts to magnitude V=15.4 occurring approximately once a month.

Special Notice #71: Next HST cataclysmic variable scheduled

October 11, 2007: The next HST object from Paula Szkody's program is scheduled to be observed during the week of October 29 through November 3. This is SDSS J074531.92+453829.5, another cataclysmic variable that is about V=19.1 at quiescence, and unknown brightness in outburst since it has never been observed to outburst. The coordinates are:

07:45:31.92 +45:38:29.5 J2000

and the AAVSO Harvard Designation and name is

0738+45 SDSS074545

Special Notice #63: Outburst in HS 2331+3905 [V455 And]

September 4, 2007: The WZ Sge-candidate object HS 2331+3905 [V455 And] has been reported in outburst on VSNET by two observers. This object was last reported as fainter than 14.6 on JD 2454347.3931 (Sept 3, 2007, 21:26 UT), and has now been detected at 14.59 and 14.4 by observers in Japan. HS 2331+3905 has never been observed in outburst before, and observations are strongly encouraged.

Special Notice #67: Special Notice #66 on V455 AND Corrected

September 12, 2007: Due to a typographical error, the lead sentence of AAVSO Special Notice #66 was garbled. My sincere apologies! Here is the correct version:

According to IAU Circular No. 8868 (Daniel E. W. Green, editor), N. N. Samus, Institute of Astronomy, Moscow, reports that the dwarf nova cataclysmic variable 2328+38 HS 2331+3905 has been assigned the official name V455 And. The AAVSO validation file has been changed to reflect this new name. Please use V455 AND when reporting observations.

Special Notice #66: HS 2331+3905 Named V455 And

September 12, 2007: According to IAU Circular 8868 (Daniel E. W. Green, editor), N. N. Samus, Institute of Astronomy, Moscow, reports that the dwarf nova cataclysmic variable 2328+38 HS 2331+3905 is now V455 And, and HS 2331+3905 has been assigned the official name V455 And. The AAVSO validation file has been changed to reflect this new name. Please use V455 AND when reporting observations.

V455 AND is located at RA 23:34:01.55, Dec +39:21:42.9 (J2000)

Special Notice #76: Support for HST observations of SDSS074545, update

October 29, 2007: We have been informed by Paula Szkody that HST observations of SDSS074545 have been tentatively scheduled for the night of 2007 October 31/Nov 01 UT (approximate JD 2454405.56). Observations are pending ground-based confirmation that this cataclysmic variable is not in outburst and is thus faint enough to safely observe with HST. This decision will be made on the afternoon of Wednesday, 2007 October 31 UT, and so observations are critically needed during the night of 2007 October 30/31 UT (JD 2454404.5).

Special Notice #79: Update of Alert Notice 361: HST Observations of SDSS091908

November 12, 2007: This is an update to the Request for Observations given in Alert Notice 361, on upcoming Hubble Space Telescope observations of SDSS091908, a cataclysmic variable with a pulsating white dwarf primary.

Alert Notice 586: Status of 20 cataclysmic variables needed for WHT campaign

July 7, 2017: Roque Ruiz-Carmona (Ph.D. candidate, Institute of Mathematics, Astrophysics and Particle Physics, Radboud University Nijmegen, The Netherlands) has requested AAVSO assistance in determining the status of 20 eclipsing cataclysmic variables (CVs) in order to select one system in outburst for observation with the William Herschel Telescope (WHT) at La Palma, to detect and study spiral density waves in the system. The WHT observations will begin on 2017 July 11 UT.

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