HST/COS is scheduled to observe the SU UMa variable BB Ari 2013 September 27; it must be at quiescence for HST to observe it safely. There is a possibility (recent observations are somewhat conflicting) that a normal outburst might be commencing.
YOUR OBSERVATIONS ARE ABSOLUTELY ESSENTIAL TONIGHT AND TOMORROW to know the status of BB Ari. Please see AAVSO Special Notice #371 for details.
Many thanks and good observing - Elizabeth Waagen, AAVSO HQ