Fourth contact (C4) — the end of the eclipse
Fourth contact is the moment the discs separate and the eclipse is over at your location. Like first contact, it is undramatic and easy to miss.
Fourth contact, C4, is the instant the two discs separate — the Moon's trailing limb leaving the Sun's, external tangency on the far side, the mirror of first contact. The eclipse is over at your location. In a partial eclipse it is one of only two contacts there are, which is how most of the world meets it.
An anticlimax by design
Most people who travel for a total eclipse have packed up well before C4. The 70 to 85 minutes after third contact are the same geometry as the 70 to 85 before C2, running backwards, and they are nothing like it to sit through: the extraordinary part is behind you, and what remains is a shrinking notch that takes a filter to see at all.
It is still the end of the event, and it is still the moment this app stops the clock — C4 is what closes the timetable, and what a log or a timelapse should run to. Where an eclipse is caught at sunset the Sun sets partly eclipsed and C4 never happens above the horizon; the panel still lists the computed moment, with a negative solar altitude beside it to say so.
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Updated 13 August 2026.