Contact — the four moments the discs touch
The four contacts are the moments the discs of the Sun and Moon appear to touch. They are the skeleton of any eclipse timetable, and every one is local.
A contact is a moment at which the apparent discs of the Sun and Moon touch, and together they are the timetable of the event. How many you get depends on where you stand, not on the eclipse: four from inside the path of totality or annularity, two — C1 and C4 — from everywhere else, including from a spot that sees a 99% partial phase of a total eclipse.
The four exist because two different shadows arrive. C1 and C4 bracket your time inside the penumbra; C2 and C3 bracket your time inside the umbra, which is why only observers the umbra reaches get them at all.
They belong to a place, not to the eclipse
This is the thing to understand about contact times: they are different for every observer. Neighbouring towns see the same contact a minute or two apart, and the difference across a country is tens of minutes. Quoting a contact time without a location says nothing.
That is why this app computes them from the coordinates you have chosen rather than listing one set for everybody. The one time that belongs to the eclipse as a whole rather than to an observer is greatest eclipse.
Typical intervals, for a total eclipse seen from the path: about 70 to 85 minutes from C1 to C2, the same again from C3 to C4, and two and a half to three hours end to end.
When there are fewer than four
An eclipse caught at sunrise or sunset can lose contacts on one side — the Sun is already partly eclipsed when it rises, so there is no first contact to observe from that location. A grazing eclipse at the very edge of the path can bring C2 and C3 within a second of each other.
Both cases are real, and the timings panel still lists every contact rather than dropping the ones you cannot see: a contact the geometry produces below your horizon is shown with the Sun's altitude beside it, which will be negative. Read the altitude, not just the time.
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Updated 13 August 2026.