Total solar eclipse. Time-lapse montage of 35 images showing the progression (from top left to bottom right) of a total solar eclipse from just after first contact (top left) to totality (centre) and just before last contact (bottom right). The diamond ring effects just before and after totality are also shown. Total solar eclipses occur when the Moon passes directly in front of the Sun. Total solar eclipses usually occur less than once a year, and can only be seen from a small area of the Earth's surface. At totality, the solar atmosphere (corona, white) becomes visible. This total solar eclipse was observed from Idaho in the USA on 21 August 2017. Totality lasted for just over 2.5 minutes. The time from first contact to last contact was just over 3 hours.