Just a quick note to say that the Vernal Equinox, or Spring Equinox, (in the Northern hemisphere) takes place this afternoon at 15.33 UTC (which is 3.33 pm local Irish Time). Many people regard this as the first day of spring. The weather in Maynooth is certainly spring-like. Of course in the Southern hemisphere this is the Autumnal Equinox.
The date of the Vernal Equinox is usually given as 21st March, but in fact it has only been on 21st March twice this century so far (2003 and 2007); it was on 20th March in 2008, has been on 20th March every spring from then until now, and will be until 2044 (when it will be on March 19th).
People sometimes ask me how one can define the `equinox’ so precisely when surely it just refers to a day on which day and night are of equal length, implying that it’s a day not a specific time?
The answer is that the equinox is defined by a specific event, the event in question being when the plane defined by Earth’s equator passes through the centre of the Sun’s disk (or, if you prefer, when the centre of the Sun passes through the plane defined by Earth’s equator). Day and night are not necessarily exactly equal on the equinox, but they’re the closest they get. From now until the Autumnal Equinox days in the Northern hemisphere will be longer than nights, and they’ll get longer until the Summer Solstice before beginning to shorten again.

Loughcrew (County Meath), near Newgrange, an ancient burial site and a traditional place to observe the sunrise at the Equinox
Here in Ireland we celebrated Saint Patrick’s day on March 17th, the reputed date of his death in 461 AD. Although he may have been born in Wales, nobody really knows for sure precisely where St Patrick was born, though, so it would be surprising if the when were any better known.
In any case, it wasn’t until the 17th Century that Saint Patrick’s feast day was placed on the universal liturgical calendar in the Catholic Church. In the thousand years that passed any memory of the actual date was probably lost, so the Equinox was perhaps rebranded for the purpose.
The early Christian church in Ireland incorporated many pre-Christian traditions that survived until roughly the 12th century, including the ancient festival of Ēostre (or Ostara), the goddess of spring associated with the spring equinox after whom Easter is named. During this festival, eggs were used a symbol of rebirth and the beginning of new life and a hare or rabbit was the symbol of the goddess and fertility. In turn the Celtic people of Ireland probably adapted their own beliefs to absorb much older influences dating back to the stone age. St Patrick’s Day and Easter therefore probably both have their roots in prehistoric traditions around the Spring Equinox, although the direct connection has long been lost.
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