Validated flash detections and suspected flashes at estimated magnitudes in R band against lunar phases. Black dotted vertical lines denote the quarters (90° and 270°) and the new Moon (180°) phases. Gray vertical solid lines correspond to the boundaries of lunar phases (110° and 250°) empirically set to separate the lunar phases with different m_R, lim. Blue and reddashed horizontal lines represent the two upper limits of m_R of flash detections according to the lunar phase.