October 25, 2011: Dr. Paula Szkody (University of Washington) has requested the help of AAVSO observers in monitoring the WZ Sge-type cataclysmic variable SDSS J080434.20+510349.2 (SDSS0804+51) in support of Hubble Space Telescope ultraviolet spectroscopic observations scheduled for 20:52:40 - 23:32:35 2011 November 3 UT (the night of Wednesday, November 2/3) (JD 2455869.36991-.48096). Nightly observations are requested beginning immediately and continuing through November 30. This monitoring is crucial to these observations. This campaign is similar to Dr. Szkody's one on V455 And (see AAVSO Alert Notice 448).
The primary purpose of the monitoring is to know whether SDSS0804+51 is in quiescence; if it is in outburst it will be too bright for the HST instrumentation. The decision whether to go forward with the HST observations will be made the evening of Tuesday, November 1/2, so the nights of October 31/November 1, November 1/2, and 2/3 are the most critical for observations to be reported. Positive visual or V observations are preferred if at all possible, but fainter-than observations below V=14 are useful (<14.0 or fainter). Therefore, nightly observations are sufficient for now; 2-3 observations per night are requested during the nights of October 31/November 1 through November 4/5, after which nightly observations may be resumed.
For CCD observers, Dr. Szkody writes, "[We] will also be summing the spectra to obtain UV light curves. Simultaneous photometry [shortly before, during, and after the HST observations] would be great for CCD observers. 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."
During quiescence SDSS0804+51 is around magnitude V=17.5. According to observations in the AAVSO International Database, the last outburst of SDSS0804+51 occurred September 22, 2010, when it reached visual magnitude 12.2 and was brighter than about magnitude 15 until October 19, 2010.
SDSS J080434.20+510349.2 (SDSS0804+51, AUID 000-BCY-525) is located at the following (J2000) coordinates:
RA: 08 04 34.20 Dec. +51 03 49.2
Charts for SDSS J080434.20+510349.2 may be plotted using AAVSO VSP.
Please report all observations of SDSS0804+51 to the AAVSO as SDSS J080434.20+510349.2 or SDSS0804+51.
Thank you for your observing efforts and valuable observations!
This AAVSO Alert Notice was prepared by Elizabeth Waagen.
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