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Alert Notice 450: Request for observations of SDSS J080434.20+510349.2‭ ‬in support of HST observations

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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