Explanation of Umbral Contacts and Extremes for Solar Eclipses

by Fred Espenak

The following tables contain brief explanations for the various contact times of the Moon’s umbral or antumbral shadow with Earth’s surface during an eclipse of the Sun.

Contacts of Umbral Shadow with Earth
Contact Event Contact Description
First External ContactU1Instant of first external tangency of the umbral or antumbral shadow cone with Earth’s surface
(edge of umbral or antumbral shadow first falls on Earth - total or annular eclipse begins)
First Internal ContactU2Instant of first internal tangency of the umbral or antumbral shadow cone with Earth’s surface
(entire umbral or antumbral shadow first falls on Earth)
Last Internal ContactU3Instant of last internal tangency of the umbral or antumbral shadow cone with Earth’s surface
(entire umbral or antumbral shadow last falls on Earth)
Last External ContactU4Instant of last external tangency of the umbral or antumbral shadow cone with Earth’s surface
(edge of umbral or antumbral shadow last falls on Earth - total or annular eclipse ends)

Extreme Northern and Southern Path Limits of Umbra
Contact Event Contact Description
North Extreme Path Limit 1N1Northern limit of the umbral or antumbral shadow at the start of the central path
South Extreme Path Limit 1S1Southern limit of the umbral or antumbral shadow at the start of the central path
North Extreme Path Limit 2N2Northern limit of the umbral or antumbral shadow at the end of the central path
South Extreme Path Limit 2S2Southern limit of the umbral or antumbral shadow at the end of the central path

Extreme Limits of the Central Line
Contact Event Contact Description
Extreme Central Line Limit 1C1Starting point of the central line on Earth's surface
Extreme Central Line Limit 2C2Ending point of the central line on Earth's surface