text: how often is a eclipse?   eclipses of the sun and moon usually happen six months apart and then in a fortnightly patten when they do. as an example, there will be a penumbral lunar eclipse on march 14th 2006 and about a fortnight later there will be a solar eclipse on march 29th, similarily on september 7th 2006 there is a partial eclipse of the moon followed by a solar eclipse on september 22nd 2006.