Along the top of the image are posted local times. LST along with latitude and longitude is essential to determine the angle of the suns rays at the surface. Local solar time is determined from the longitude of the point in question. This time differs from local standard time with which we are all familiar. Time zones are ideally 15 degrees in longitude wide, and in that time zone all clocks are set to the same time.
Solar time is unique for each longitude.
In the top panel, the ECT posted on the far left is at 1443Z, which corresponds to a local solar time of 0224. This is 00Z at the end of the day. Subsequent to this ECT, the satellite traveled about halfway toward the top of the orbit, or somewhere around 10 more minutes before the day ended. Applying the sanity check to this orbit shows that the subsequent ECT occurred at 0016UTC, which makes the start time of the orbit look about right. Data contained in the science data files begin and end differently from that of the browse products.