## Duration of Eclipses

Demonstrate an understanding that the duration of total solar and lunar eclipses are different and that they do not occur every new and full Moon

The length of a solar eclipse depends on where the Moon's shadow falls on the Earth's surface and where the observer is on that shadow. During a solar eclipse the maximum possible duration of totality is 7 minutes 31 seconds.

The longest eclipse in this century occured in July 2009 and lasted for 6m 39s. The 20th century's longest was 7 minutes and 8 seconds.
The maximum duration of an annular eclipse is 12 minutes 30 seconds as the smaller disc of the Moon takes longer to move across the larger disc of the Sun.

During a total lunar eclipse the Moon's passage through the Earth's shadow can theoretically last up to 1 hour and 40 minutes.

The maximum number of eclipses in a calendar year is seven. There may be two combinations: Four solar and three lunar eclipses, or five solar and two lunar eclipses. These solar eclipses may be total, annular or partial.

###### Data
Type of Eclipse Maximum Duration
Solar (Total) 7 minutes, 30 seconds
Solar (Annular) 12 minutes, 30 seconds
Lunar (Total) 1 hour, 40 minutes
###### Questions

Why do lunar eclipses last longer than solar eclipses?

###### Data
Max. Possible combinations of eclipses Solar Lunar
a) 4 3
b) 5 2
###### Did you know?
• Eclipses last a day, starting at one part of the globe at sunrise and ending at sunset.
• Eclipses occur in a similar place every 18 years and 11 days because the Moon, Earth and Sun have run a saros cycle.