Why Maghrib and sunset are not always the same moment

Astronomical sunset is the moment the sun's disc drops below the horizon. Ja'fari discussions of Maghrib commonly reference the disappearance of the redness in the eastern sky, which happens after that moment.

Services implement this in different ways, most often as an interval applied after sunset. The size of that interval and its justification differ by provider and by the ruling being followed.

This is a question where a specific ruling matters more than a general explanation. Ask your marja or local centre rather than adopting a default from an app.

Publishing a fixed number of minutes after sunset would be misleading. The live timetable instead names the selected Qum or Tehran profile and calculates Maghrib from its documented solar-depression angle.

This is an educational summary drafted editorially and awaiting scholarly review. It is not a personal religious ruling; your marja's guidance and your local religious authority take precedence.