September 5, 2013: HST/COS is scheduled to observe the WZ Sge-like SU UMa variable GZ Cet (SDSS J013701.06-091234.9) next week. Observations are scheduled for:
GZ Cet 2013 Sep. 13 12:24:02 through 19:06:54 UT
The scheduling team will likely make their final decision early on September 12, and your observations will be essential now through September 14, and particularly so September 10-14. GZ Cet is magnitude 19.32 V at minimum and may be as bright as 12.264 V at maximum, according to observations in the AAVSO International Database. A rare, normal outburst appears to have taken place 2013 August 15 UT (JD 2456520.6) when GZ Cet reached 13.9 CV.
After GZ Cet, the next target on the HST list is the SU UMa-type variable BB Ari:
BB Ari week of 2013 September 23-30 (to be revised)
Giving top priority to GZ Cet, please observe BB Ari closely through the end of September. BB Ari can be as faint as magnitude 19.898 V at minimum and may be as bright as 13.576 V at maximum, according to observations in the AAVSO International Database.
As with all the HST/COS targets in this campaign, it isn't just that it is important to know how bright the variable is 24 hours before the scheduled HST observation time, it is critical to know that the variable is not brighter than the safe limit on the HST instrumentation. Thus, observations during the two to three nights before the HST time are absolutely essential.
GZ Cet R.A. 01 37 01.05 Dec. -09 12 34.2
BB Ari R.A. 02 44 57.71 Dec. +27 31 09.3
Charts may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp).
Please report observations as soon as possible to the AAVSO International Database using the name GZ CET (the primary VSX name) and BB ARI, respectively. If an outburst is detected, please report observations immediately. Many thanks!
Details of the HST/COS CV campaign and specific observing instructions may be found in AAVSO Alert Notice 471 (http://www.aavso.org/aavso-alert-notice-471). Related AAVSO Special Notices may be found via the Observing Campaigns page (http://www.aavso.org/observing-campaigns). AAVSO Special Notice #364 (http://www.aavso.org/aavso-special-notice-364) is the most recent one that pertains to the campaign.
This AAVSO Special Notice was compiled by Elizabeth O. Waagen.
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