Distribution of the RHESSI flares that occur when the HSB-Earth was at central meridian, separated by the polarity change at the boundary: left (blue) for negative leading positive (−, +), right (red) for positive leading negative (+, −). In the top row we show the flares during Cycle 23 (Feb 2002 to July 2008) and bottom row for Cycle 24 (July 2008 to Feb 2016). The green lines indicate the hemisphere in which the HSB is located. The dashed circle indicates the approximate region from which RHESSI cannot determine a flare’s location. The purple dashed lines indicate ±25° of meridian, the range used for the histograms in Fig. 3.