Peak and semi-duration define each pair
Each available shadow phase has a semi-duration measured from peak. Subtracting that interval gives the begin contact; adding it gives the end contact. The full phase duration is twice the semi-duration, so all contacts remain tied to the same event.
Penumbral begin precedes umbral begin when an umbral phase exists, peak lies between the corresponding begin and end instants, and the outer phase ends last. A total eclipse adds a narrower totality interval inside the umbral interval. A partial event has no totality contacts, while a penumbral event has neither umbral nor totality contacts.
Global timing is not local visibility
An eclipse peak is one physical instant worldwide, although its formatted clock time and civil date depend on the chosen display zone. Latitude and longitude do not change that global event instant.
A local observer may have the Moon below the horizon for some or all contacts. Clouds, daylight, terrain, and buildings add further constraints. The contact table gives global shadow geometry; city- or country-level visibility depends on separate observer conditions.
Worked example
Worked partial-eclipse example
From an input of 26 August 2026 at 12:00 UTC, the next event is the global partial lunar eclipse of 28 August:
- Penumbral phase
- 01:23:36–07:02:02 UTC, about 338 minutes
- Umbral phase
- 02:33:24–05:52:14 UTC, about 199 minutes
- Peak
- 04:12:49 UTC
- Totality
- not present for this partial event
Peak falls inside both available intervals, and the umbral phase is shorter than the penumbral phase. An absent totality value is meaningful classification logic, not missing content.
Read before comparing
Reference conditions
- Displayed contact times are rounded for reading after the event instants are determined.
- Global contacts give event timing; local horizon visibility depends on the observer's place and conditions.
- Totality contacts exist only for total eclipses; partial and penumbral events have no totality interval.
Next step
Use the working calculator
Calculate another exact instant with the same reference frame and conventions described on this working sheet.