Alert Notice 366: Request to monitor SDSS133948 for HST Observations

January 18, 2008: Dr. Paula Szkody (University of Washington) and collaborators have
requested our help in monitoring the cataclysmic variable SDSS133948 (SDSS J133941.11+484727.5) for upcoming Hubble Space Telescope observations. The HST observations are scheduled to be made starting 2008 January 24, 21:30 UT (JD 2454490.3958) through the afternoon of 2008 January 25, ending at approximately 15:15 UT  (JD 2454491.1354).  Dr. Szkody requests monitoring of this object beginning immediately (2008 January 18 UT), and intensive monitoring during the 24-48 hour period surrounding the scheduled time of observations.

SDSS133948 (AAVSO Designation 1335+49) is located at RA 13:39:41.12 , Dec +48:47:27.5 (J2000)

SDSS133948 is a cataclysmic variable not previously seen in outburst, and is being observed as part of a larger study of pulsating white dwarf primaries in cataclysmic variables. In particular, Szkody and collaborators are investigating the effects that higher temperatures and larger rotation velocities caused by accretion have on the pulsation behavior.

This object is faint at quiescence, with V=17.7.  AAVSO observations are requested to ensure that the object remains in quiescence when observed with HST, as it could damage the instrument if it were to go into outburst. AAVSO observations will be used to make a "go"/"no go" decision at 21:41 UT on January 24 (JD 2454490.4035), and will also be used in the analysis of the resulting data.  Observations are requested to continue through the end of the science observing window.  Science observations will begin at approximately 06:15 UT on January 25  (JD 2454490.7604) and end at approximately 15:15 UT (JD 2454491.1354).

Observers are asked to monitor SDSS133948 nightly beginning immediately (2007 November 07 UT). Visual observers please observe as normal, and report any "fainter than" estimates using the faintest comparison star magnitude you can reach if unable to detect SDSS133948 itself. CCD observers are asked to use filters during observations if available; V filter is preferred, but B,Rc, and Ic may also be used. Detection of the variable itself is not required unless you can reach V=17.7 in reasonable time, but please use sufficient exposure to detect at least the V=15.045 comparison star (AUID 000-BFR-715; RA 13:39:09.21 Dec +48:50:10.1) with a S/N of 10 and report the observation as a "fainter-than" measure.

Please observe this object as often as possible for the duration of the week using the observing procedure outlined above, and submit data as soon as is possible via WebObs. In the event of an outburst, please contact the AAVSO immediately. 

Please submit data to the AAVSO using the name "SDSS133948" (AAVSO Designation 1335+49).

Charts for SDSS133948 are available at this URL:

For more information on this campaign, visit the following URL:

This campaign is being organized at AAVSO HQ by Dr. Matthew Templeton.



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