Easter holidays

The greatest Christian festival of the year is Easter. It is either in March or in April, and millions of people joyously observe Christ’s resurrection. This holy day never comes before March 22 or after April 25.

When is an Easter? That, of course, is celebrated on the first Sunday after the paschal moon, which is the first full moon that occurs on or next after the vernal equinox, March, 21st. So all you need to do is look at the sky? Afraid not. For the moon in question is not the real moon, but a hypothetical moon.

In 2010 Easter is on 4th of April.

This one goes round the earth one month in 29 days, the next in 30 days, though with certain modifications to make the date of both the real and fictional full moons coincide as nearly as possible. It yields a date for Easter that can be as early as March 22nd and as late as April 25th.

Today, Easters variability suits antiquarians, and the makers of pocket diaries, many of which devote a Full page to the calculation of Easter in perpetuity.

But, nearly 1,700 years on, it does not suit those in (mostly European) countries such as Britain and Germany where both Good Friday and Easter Monday are public holidays. Early Easters are too cold to enjoy. Late Easters are jammed up against the May Day public holiday.