Equinox or equilux? The nights are getting longer, don't forget the headlamp.

September Sunset

Today is the Autumn Equinox, which I've just learnt I've misunderstood all my life. Until a few hours ago I thought it was the day when the hours of light and dark were equal - after all the name means 'equal night'. Listening to the BBC weather forecast this morning my partner heard the word equilux - equal light - which neither of us had ever come across before. Was this another name for the equinox? No, turns out it's a different day and the one when the hours of light and dark are actually equal, the equinox being when they're only approximately equal. So why not just have the equilux? 

The Met Office explains the confusion. The equinox is when the sun is positioned exactly above the equator not when day and night are of equal length. "On the equinox, the length of day and night are only nearly equal. This is because the sun appears as a disk in the sky, and the top half rises above the horizon before the centre. As well as this sunlight is refracted by the Earth's atmosphere. The Sun, therefore, appears to rise before its centre at the horizon, giving more daylight than you might expect (12 hours 10 minutes on the equinox). The equilux is when day and night are equal and occurs a few days before the spring equinox, and a few days after the autumn equinox". 

It's nice to learn something new! But I am surprised I'd managed never to hear about the equilux all these years.

What matters in practical terms is that having a torch or headlamp with you becomes more important than it was not long ago. I carry a small one right through the summer but don't often use it except perhaps for finding items in the tent in the middle of the night. However as daylight hours shorten walking in the dark becomes more usual. It won't be long before starting or finishing with a headlamp becomes the norm. 

Every autumn mountain rescue teams are called out to people caught out without headlamps or torches as they haven't realised it gets darker sooner than a few weeks ago. By carrying a small headlamp year round I can't make this mistake. From this time of year onwards I carry a bigger headlamp with a longer lasting battery as well. It's much easier to swap headlamps than batteries. I also carry spare batteries or a power bank for headlamps with rechargeable batteries as well. 

If you're looking for a headlamp I've just reviewed eight for the November issue of The Great Outdoors. You can find my Best Buy, pictured below, on the TGO website