Skip to main content

AAVSO International Database

Alert Notice 595: GW Lib time scheduled for first HST observation

August 24, 2017: Further to AAVSO Alert Notice 591, Dr. Boris Gaensicke (Warwick University) informs us that the first of three HST observations in his campaign on the pulsating white dwarf-containing cataclysmic variable GW Lib has been scheduled for

2017 Aug 31 20:52:02 to 2017 Sep 1 02:12:21 UTC.

Alert Notice 594: Correction to Alert Notice 593

August 17, 2017: In AAVSO Alert Notice 593 we announced a campaign on the very long period VV Cep M2Iabe+B0/2Ve binary. The amplitude of the eclipse was wrongly given as slightly under a magnitude in the V band when it is actually around 0.1 mag. This means that the VV Cep eclipse is largely undetectable visually,  and is not a good candidate for visual observations. CCD and DSLR photometry, however, are still encouraged.

Alert Notice 593: VV Cep eclipse monitoring requested

Edit: The information given in this alert notice has been updated to correct eclipse depth values. Please see AAVSO Alert Notice 594

August 16, 2017: The AAVSO is requesting monitoring of the eclipse of the very bright Algol-type eclipsing binary variable VV Cep, predicted to have begun in June 2017 and to conclude in November 2019.

Alert Notice 592: V404 Cyg observations needed tonight for Chandra observations

August 11, 2017: Dr. Gregory Sivakoff (University of Alberta) and colleagues have requested AAVSO observers' assistance in observing the black hole X-ray transient LMXB V404 Cyg in support of Chandra observations taking place TONIGHT. The Chandra schedule is

2017 Aug 11 23:49:04.072  - 2017 Aug 12 13:42:14.730 UTC

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 590: V1117 Her observations requested

August 7, 2017: AAVSO Young Stellar Object (YSO) Section leader Michael Poxon (Great Plumstead, Norfolk, UK) requests coverage of the YSO V1117 Her.

He writes: "The peculiar YSO V1117 Herculis has undergone a second, rapid fade and recovery only a few days after its recovery from another rapid fade. Observations, both visual and multiwavelength, are encouraged, since the behaviour of this star's historical fading episodes may indicate rapidly-changing evolution of the protoplanetary clumps in the circumstellar disc.

Alert Notice 589: R Aqr coverage needed for HST and Chandra observations

August 4, 2017: Dr. Margarita Karovska (Harvard-Smithsonian Center for Astrophysics) has requested "visual, photometric, and spectroscopic observations of the symbiotic variable R Aqr in preparation for and in support of Chandra and HST observations currently scheduled for October 2017."

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.

Alert Notice 587: Observations of FI Vir (Ross 128) needed this week

July 17, 2017: Dr. Abel Méndez (University of Puerto Rico at Arecibo) has requested AAVSO assistance in follow-up observations of the flare star FI Vir (Ross 128) subsequent to his radio observations obtained yesterday (July 16) with the Arecibo and Green Bank (GBT) telescopes and the Allen Telescope Array (ATA).

Special Notice #78: SN 2007oc in NGC 7418A

November 3, 2007: The Central Bureau for Astronomical Telegrams (see CBET 1114) has announced the discovery of supernova SN 2007oc in the southern galaxy NGC 7418A. The galaxy was discovered at magnitude 13.6 on November 3.06 UT (approx JD 2454407.5). The supernova has since been detected on an image taken October 23.09 (approx JD 2454396.6) at magnitude 13.3, and is therefore in its declining phase.

The J2000 coordinates of the supernova are given as

RA: 22 56 41.77    Dec: -36 46 22.3

Pages

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484