Your pictures as equinox marks the start of astronomical autumn

The sun rises in a yellow sky over the top of Glastonbury Tor, which is a monument on the top of a hill. People stand at the base of the Tor watching. Image source, BBC Weather Watcher / mike Jefferies
ByElizabeth Rizzini
Lead Weather Presenter
  • Published

Astronomical autumn has officially started after the equinox took place in the early hours of Wednesday.

It happened at 01:06 BST on 23 September, according to Royal Museums Greenwich.

It is a precise moment in time when the Sun crosses the celestial equator and neither hemisphere is tilted towards or away from the Sun, meaning day and night are roughly equal in length across the world.

While the equinox itself cannot be seen, the day has cultural and spiritual significance for some people. Gatherings took place at sites including Stonehenge and Glastonbury Tor (pictured above), where people came together to mark the occasion and watch the Sun rise.

A heart shape is made out of conkers on the ground with the word 'autumn' spelled out in leaves above itImage source, BBC Weather Watchers / sue
Image caption,

Autumn's arrival is very clearly spelled out in photo taken in Wakefield, West Yorkshire

The autumn equinox may mark the start of astronomical autumn, but it does not necessarily mean there will be a sudden change in the weather.

The first signs of autumn are already around us with falling leaves and conkers on the ground, and as the Sun gets lower in the sky and the days shorten, temperatures generally fall as we head further into autumn.

So far this September, UK mean temperatures have been above average overall, according to the Met Office.

BBC Weather Watchers captured some beautiful equinox photos and here are a few favourites of those sent in so far.

Small shrub branches with brown and yellow leaves and to the right a huge spider web glinting in the sunImage source, BBC Weather Watchers / sue
Image caption,

A spider's web is beautifully crafted in amongst the autumn leaves

Swathes of pink and orange fill the sky with field in the foreground and a glimpse of water to the leftImage source, BBC Weather Watchers / Matt
Image caption,

The sunrise over Malborough in Devon on Wednesday filled the sky with tutti-frutti pink and orange colours

A bright red toadstool with white spots stands in amongst mossy grass, with blue sky just visible behind green treesImage source, BBC Weather Watcher / Pia
Image caption,

Fairytale-style toadstools popping up and changing autumn leaves are some of beautiful signals that autumn is here.

Although the equinox happens at the same moment everywhere, the change in hours of daylight is not the same across the UK.

The further north you go, the bigger the difference between the long days of summer and the short days of winter.

That means places in northern Scotland are losing daylight more quickly at this time of year than parts of southern England.

The fern leaves are turning red and orange in the foreground with fields behind shrouded in a low-lying mistImage source, BBC Weather Watchers / Hang Ross
Image caption,

Leaves are already turning red and oranges setting off the mist still shrouding the fields behind

The sun is just more than half way over the horizon on the sea in a vivid red and orange sky. A ship is on the silver, grey sea with trees in the foreground. Image source, BBC Weather Watchers / Daisybell
Image caption,

Sunrises like this one in Ventnor on the Isle of Wight, will will get progressively later as autumn continues

In the distance the sun rises over mountains as a yellow dot in among blue grey clouds. In the foreground are rolling hills and leaves just beginning to change colourImage source, BBC Weather Watchers / The Lonely Shepherdess
Image caption,

Around the autumn equinox the changes are particularly noticeable as sunrise gets later and sunset earlier.

What is the difference between the equinox and equilux?

The word "equinox" comes from Latin and means equal night.

At the equinox, the daylight measurement is taken from the point when the centre of the Sun is at the horizon, and is 12 hours sunrise to sunset and 12 hours sunset to sunrise.

However, it is the top edge of the Sun which is visible first at sunrise and last at sunset.

Because of light refraction - light being bent by the atmosphere - there is still light for a time when the Sun is not directly visible. This adds extra time to daylight hours.

In autumn, this means that the time when day and night are actually equal happens after the equinox.

This is known as the "equilux", which means equal light.

This year, that happens in the UK on Friday 25 or Saturday 26 September, depending on your latitude.