Although there is no simple connection between one eclipse of the sun or moon and the one immediately following, there is a cycle lasting 18 years and 10 days over which the pattern of eclipses repeats itself exactly.
Indeed it was due to a knowledge of this cycle - which they called the saros - that the ancients were able to predict eclipses of the moon. It was the rarity of solar eclipses at any given place on the Earth's surface that caused them to miss the fact that they, too, follow the same pattern.
Eclipses, like sorrows to Shakespeare's king of Denmark, come rarely as single spies but in battalions. Well, perhaps not quite battalions, but often as two or three together over a small number of weeks.
There are two periods each year called the eclipse seasons when eclipses are possible. The eclipse seasons change slowly over the saros; the average interval of repetition of the eclipse seasons is about 347 days, causing them to slip backwards by nearly three weeks per calendar year. There are usually four eclipses of the sun or moon in any year; the maximum possible number is seven - normally four solar and three lunar - while in some years there may be as few as two, both solar.
Throughout the ages, eclipses have often been regarded, at best as a bad omen, and at worst as the malign influence of an evil spirit. They signalled the death of the sun or moon, a threat to the established order, and more or less the end of civilisation at that time.
A popular concept in many cultures saw the event as an attack by a fierce monster - a dragon, a lion, or an evil serpent - which proceeded to devour the body in the heavens.
It was generally accepted that the only way of warding off this catastrophe was to create a massive row - known variously as "hullabaloo" or "pandemonium" - by banging drums and pots and pans. The noise never failed after a time to frighten the devouring monster, and forced it to release the sun or moon.
The ancient Babylonians were more refined. They countered the evil spirits of an eclipse by performing the rituals laid down for such events; they would anoint their king with oil of myrrh, then dress him in his festive clothes to kiss an old woman specially chosen for the honour.
Perhaps these ancient remedies, mutatis mutandis, might still be efficacious in warding off Ireland's evil spirits during tomorrow's big event?