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Special Notice #197: Request for time-series photometry of U Sco

March 2, 2010: Dr. Bradley Schaefer (LSU) requests intensive time-series observations of U Scorpii beginning immediately and continuing through 2010 March 4 08:00 UT (JD 2455259.83). These observations are requested in support of coincident X-ray photometry by the XMM-Newton satellite. The XMM-Newton observations, requested by Dr. Jan-Uwe Ness (ESA), will investigate the X-ray behavior of U Sco during its transition from outburst back to quiescence. These X-ray observations will likely detect flickering, and coincident optical photometry will be important to determine the physical causes of this variability and hence to better understand U Sco and its outbursts.
 
The XMM observations will commence on 2010 March 3 14:16 UT (JD 2455259.09) and continue through 2010 March 4 08:01 UT (2455259.83). Observers are asked to obtain the best time-series observations possible given the constraints of their observing system. U Sco is currently around V=15.5, and so getting good signal-to-noise is increasingly challenging. Please obtain the best signal to noise possible while keeping integration times low, preferably under five (5) minutes, and much less than 5 minutes if at all possible. Unfiltered observations are acceptable but please use a V filter if you have a larger telescope. The moon will be within 30 degrees so please be careful to avoid contamination and saturation due to moonlight.
 
U Scorpii is located at the following (J2000) coordinates:
RA: 16:22:30.78 , Dec: -17:52:42.8
 
Charts for U Sco may be plotted using AAVSO VSP (http://www.aavso.org/vsp).
 
Please report all observations to the AAVSO using the name "U SCO".
 
For more information on the U Sco outburst and its progress so far, please visit the AAVSO's information page: http://www.aavso.org/news/usco.shtml
 
This AAVSO Special Notice was prepared by Matthew Templeton.
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