We are fast approaching the time of year when we stop going into true darkness and for a couple of months we stay in what is known as astronomical twilight. That is that the sun is below the horizon but not far enough to prevent its rays brightening the sky. As such it becomes almost impossible to photograph any auroras that arrive. During this time my attention turns to photographing Noctilucent Clouds - I wrote a blog about these last May.
However before we get to this stage of the year, we have the Spring Equinox to go through and this fingers crossed should provide us with a good chance of getting some late season Aurora images. March has already had some strong Aurora activity. Unfortunately it has also coincided with a big moon and the usual wall to wall cloud cover that seems to exist whenever the conditions align for a decent display, especially at the latitude that I live at in Yorkshire. That said there have been some great photos posted from up in Scotland this week when gaps in the aforementioned clouds allowed the briefest of glimpses.
Looking at the long range aurora forecast then between 18th - 21st March then a good amount of activity is predicted. It has become possible to forecast possible auroras more accurately in advance due to increase technology and us knowing where the coronal holes are on the sun. More importantly we know when the will be facing earth and can then predict how long the particles that they eject will take to arrive. Of course with all Auroras nothing is ever guaranteed.
This brings me onto the title of this blog, Equinox Auroras. Over the past few years, strong auroras have appeared around the Autumnal and Spring Equinox's and this year the pattern has continued. Wanting to fully understand the reason why, I did a little research and came across the following extract on www.aurora-nights.co.uk
The equinox is the time or date (twice each year) at which the sun crosses the celestial equator and when day and night are of equal length. This date is about the 21st March (Spring Equinox) and 23rd September (Autumn Equinox).
During the equinox there is generally periods of high geomagnetic electrical disturbance and during these periods the earth’s axial tilt aligns us at the peak angle relative to the sun to “accept” sun particles, and therefore see the Northern Lights.
The “Russell-McPherron” hypothesis explains this in much more scientific language but basically the high geomagnetic electrical disturbance (up to twice as many geomagnetic storms), combined with the tilt of the earth’s axis at that time
mean the sun and earth’s geomagnetic field and solar winds all come into alignment and therefore encourage an enhanced chance of the particles emitted from the sun entering our atmosphere.
So keep checking your aurora apps, look out for clear skies over the coming weeks and fingers crossed you might get a spectacular show. For help around how to photograph the night sky, don't forget that my eBook is available for a free download at.