Temporal evolution of a QSEB and illustration of the detection method. The top row shows a series of Hβ line core images. Every third image is shown as the cadence is 8.6 s. The second row shows the corresponding Hβ red wing images. The third row shows the locations of the selected QSEB RPs shown in Fig. 2; the locations of RP 0–8, RP 9–15, and RP 16–23 are indicated by blue, green, and red, respectively. The bottom rows shows the corresponding binary masks of QSEB detections after the morphological operation. The arrow in the third row shows the direction toward the nearest limb.