Special Notice #304: HST COS observations of SDSS J001153.08-064739.1 scheduled

October 31, 2012:  Further to AAVSO Alert Notice 471 (Gaensicke, Patterson, and Henden) and AAVSO Special Notice #298, the HST COS (Cosmic Origins Spectrograph) far ultraviolet observations of THE NEXT TARGET from the list, the dwarf nova-type cataclysmic variable

                           SDSS J001153.08-064739.1,

have been scheduled for 2012 November 9 20:42:29 UT through 2012 November 10 04:57:33 UT.

*** At this moment, however, the HST COS observations of 1RXS J023238.8-371812 which have been scheduled for 2012 November 1 22:52:28 UT through November 2 07:09:06 UT have highest priority (AAVSO Special Notice #302). Please focus on this system until at least a few days after the HST window, but begin to observe SDSS J001153.08-064739.1 when possible in preparation for the intensive monitoring to come.***

Extensive coverage in the 48 hours preceding the HST window is crucial, as the HST scheduling team will make a go/no-go decision in the 24 hours preceding the observations. They will need to know whether the system is in quiescence, as if it is too bright it will damage the instrumentation and the observations will be cancelled.

Positive observations, if at all possible, are preferred to fainter-thans so as to know the actual magnitude of the system. During quiescence SDSS J001153.08-064739.1 is around magnitude V=17.8 (magnitude 15 in outburst).

Coordinates:  R.A. 00 11 53.08     Dec. -06 47 39.2     (2000.0)

As instructed in AAVSO Alert Notice 471, for CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. B filter would be best for a light curve, although for the magnitude estimates, a V measurement would be best. An uninterrupted light curve would be better than cycling between filters. This target is likely too faint for positive visual observations, but if possible they are welcome, as are visual fainter-than observations fainter than magnitude 15.0.

Charts for SDSS J001153.08-064739.1 may be created using VSP (www.aavso.org/vsp).

Please report observations promptly to the AAVSO International Database using the name SDSS J001153.08-064739.1. If you see the target in outburst, please contact the AAVSO immediately and post a message to the Observations and Campaigns & Observations Reports forum (http://www.aavso.org/forum).

If you have been observing this star, thank you from us and from the astronomers - please continue! If you can add this star to your program through November, please do, and thank you. Your observations will be crucial to the success of this campaign and are greatly appreciated. Many thanks!

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.

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