Panel (a): Full-disc AIA 193 Å image taken at 06:00:04 on 28 October 2018, around the central meridian passage of an ECH magnetically connected to PSP during its first solar encounter. The ECH is bounded by the rectangular box. Panel (b): Sub-image of the AIA 193 Å image of panel (a), corresponding to the rectangular box in panel (a). The manually-selected ECH boundary is over-plotted with dashed green lines.