As explained by the Instituto de Astrofísica de Canarias (IAC), the minimum number of annual eclipses is four (including eclipses of the Moon due to penumbra), two eclipses of the Sun, total or annular, and two eclipses of the Moon. This happened in 1999, 2003, 2005, etc.
The two eclipses of the Sun occur one in each eclipse season , that is, at the times of the year in which the necessary conditions exist (situation of the Sun, the Moon and the Earth) for this type of phenomenon to occur. These configurations take place two or three times a year, specifically every 173.31 days .
Normally, in a year only one eclipse season is complete . But from time to time, two full eclipse seasons can occur in a calendar year. It may also happen that the two eclipse seasons in a year each contain three eclipses . But also, as the eclipse year is shorter than the calendar year, a third eclipse season can take place, as happened in 2000, 2001, 2009, 2010 and 2011, although in this case the eclipse seasons are not complete and at most we find six eclipses .
