Participation to AAVSO Observing Campaign of BZ UMa - Apr 19th, 2004

Following the February 2004 outburst of BZ UMa (see here), the AAVSO decided to launch an intensive observing campaign of BZ UMa at quiescence, in an effort to shed more light on the system. Aim of the observing campaign was to create a detailed 24-hour light curve, through intensive observations on Apr 17/18 and Apr 19/20.

Unfortunately, we were clouded out at CBA Belgium Observatory on the first campaign night. However, on Apr 19/20, 2004 skies were extremely clear, allowing an uninterrupted CCD observation session, using the 0.35-m f/6.3 telescope and unfiltered SBIG ST-7XME.

The resulting light curve is shown below. Most striking feature in the 6-hours light curve undoubtly is the "flare" around JD 2453115.375 UT, when the system brightened by about 0.76 mag  in less than 15 minutes. This "flare" is not an artefact, and was independently observed by the team of CBA Finland.