Home > Uncategorized > Happy Spring Equilux 2012

Happy Spring Equilux 2012

Today, Saturday 17 March 2012,  it is the Spring Equilux throughout the UK (and possibly elsewhere too*) meaning that there are almost exactly 12 hours between sunrise and sunset.



This date differs from the Spring, or Vernal, Equinox (2321 GMT on Sunday 20 March 2011) for a variety of reasons, which I explain in a previous post but here is a list of sunrise / sunset times for a variety of towns and cities throughout the UK:

Town / City Sunrise Sunset
Aberdeen 0617 1817
Glasgow 0626 1825
Belfast 0633 1832
Newcastle 0615 1815
Manchester 0618 1817
Birmingham 0617 1816
Cardiff 0621 1821
London 0610 1810

As you can see the time between sunrise and sunset is not exactly 12 hours everywhere but this is the day of the year when that is closest to being true everywhere*. Yesterday the sun rose a couple of minutes later and set a couple of minutes earlier, and tomorrow the sun will rise a couple of minutes earlier and set a couple of minutes later, as the days lengthen.

Also, the reason that sunrise and sunset does not occur at the same time everywhere* is due mainly to the longitude of the town, the further east a town is the earlier it sees the sun in the morning, and the earlier it loses it again at night.

So happy Equilux everyone*!

* interestingly, the equilux does not occur on the same same day for everyone, it depends on your latitude. The closer you are to the equator the earlier the date of your equilux. For example the equilux in most US cities occurred yesterday, 16 March, and in cities near the equator there is never a day with exactly twelve hours between sunrise and sunset! Take Quito, the capital city of Ecuador (latitude 0 degrees 14 minutes south) for instance. The length of day there only ever varies between 12 hours and 6 minutes long and 12 hours and 8 minutes long!

  1. March 18, 2012 at 03:47

    You know, I’ve been into astronomy since I was 6 and had honestly never heard of that term – you learn something new every day :)

    I’m trying to put together a new blog – ABC Astronomy (Astronomy Basics for Children) – would you be interested in making contributions? It’s not off the ground yet but I’m looking for some co-authors / editors / administrators.

    Obviously it’s aimed at children, but with a particular emphasis on shared activities with parents.


    If not, would you mind if I reblogged anything of interest from your site?

    Clear skies!

    • March 20, 2012 at 12:58

      I’d be happy to contribute; also if you wanted to use material from this blog just ask first, and I’ll be happy to let you have it, assuming it’s linked back. Thanks

  2. Karen
    March 20, 2012 at 22:22

    Ah ha! I’ve been searching awhile trying to figure why everyone kept saying today was exactly 12 hours long when according to other sources it was in fact several minutes longer than 12 hours. My equilux was the March 16 or 17. How would you determine the exact equilux for my location? Also I noticed that the sun does not rise or set exactly east (90E) or set west (270W) until March 19. Why don’t the 2 dates coinside? Is it due to latitude? I’m having a difficult time trying to figure out why.
    Thanks for any information
    Karen :o)

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