The Non Daily Express Guide To Aurora Viewing

You can’t have missed it on social media these past couple of days. Everywhere you look, there are images of stunning aurora shots, the skies emblazoned with green, the promise that this weekend you might just be able to pick off that ‘bucket list’ item at long last - seeing the northern lights! And, better yet, you don’t even need to go to Iceland to see it - Portrush will do!

It almost feels like it’s too good to be true, perhaps…?

Perhaps. But let’s see if we can get behind the hype and think about what we will actually see.

1. Is it possible?

The sunspot, imaged on Saturday morning in my garden!

On Wednesday 20 March, a sunspot on the Sun named 2736 gave off a solar flare that produced a Coronal Mass Ejection (CME), one of the things that can produce aurora displays on Earth. It normally takes about 3 days to travel between the Sun and our planet, which means that strike time is due to be sometime on Saturday 23 March. So, yes, aurora is possible tonight.

But…

It was a relatively small solar flare (C class; there are two higher classes, M and X, which are much more likely to produce aurora in the mid latitudes) and it wasn’t aimed directly at us.

All that to say:

A small CME could give us a glancing blow later, producing a relatively modest aurora display.

Mmmmmm, I don’t think the Daily Express are going to be coming looking for me to join their team of headline writers anytime soon…

That’s what we know for now. All of it.

So, are the reports maybe just hyped a little bit too much? Yes. Yes they are.

But…

2. Is it probable

When the CME arrives at Earth, we will get more data from it and know if things are looking more exciting for later. About an hour before the CME arrives, it passes a satellite orbiting between the Earth and the Sun whose job is to monitor the solar wind as it comes to us. That data will be streamed straight back to Earth, and then we’ll begin to be able to make better calls as to what will happen later.

We are looking for the solar wind to be strong, and with a decent magnetism. The stronger it hits, the more power it can input into our atmosphere.

But we will also be looking for it to be aligned properly. Our planet has a magnetic field. The CME also has a magnetism. If they are aligned right, it allows the aurora to travel further south towards the mid-latitudes (think of bar magnets - opposite polarities attract). If you have heard talk of the Bz, then that’s the thing that measures the magnetic orientation and is the key one we’re looking for. Negative Bz is a Good Thing.

As we head towards the afternoon, we’ll begin to see first if/when the CME hits, and also then what its characteristics are like. Only by late afternoon/early evening will we be in a position to make a decent call as to whether or not it will be probable. Watch this space.

3. What time will it be at?

It’s possible at any time after dark. That’s about all we can say!

4. What will I see?

Remember, this is only a C class flare, giving a glancing blow, so the chance are for a modest display. If that’s the case, you’ll not see the colour with the naked eye. Look instead for a band of slight enhancement along the northern horizon. If you have a camera on a tripod that can take long exposures, you might be able to pick up colour.

Toggle between these two images to see the difference between what the camera sees and what you can see with your eyes.

That said, aurora displays follow a cycle when they’re happening and have different phases. Every few hours, you can get an increase in intensity of display (called a sub-storm). When that happens, the aurora will intensify and become brighter, and you might even get treated to some pillars of light going up into the sky. If you see those, they will look like World War 2 search lights. Again, it’s highly unlikely you’ll see any colour.

Also, in terms of viewing later, an 88% illuminated Moon is due to rise around 22.00, so it will wash out a lot of what could be visible with the naked eye.



5. Where should I go?

Anywhere away from light pollution with a clear view towards the northern horizon. The Causeway Coast is good if you’re living in Ireland, but not necessary.

A little bit of etiquette. Be safe - use a head torch to find your footing. But keep your torches off as much as possible, as others will be there trying to enjoy the view and maybe take photos. Watch headlights in your car too. Don’t sit with them on for too long!

6. How do I photograph the aurora?

  • You need a camera that can be set to long exposures and a tripod

  • Open up the aperture as wide as it can go (f2.8 is ideal)

  • Set the exposure to 30 seconds (unless you’re using a zoom lens. That will have to be shorter exposure then).

  • Adjust the ISO to get the exposure right, checking the histogram on your camera.

  • Shoot in RAW to give you most options when post processing your shot

Above all, enjoy the experience. Seeing the northern lights dance in the sky above you is truly amazing.

So the hype is there. The articles are over-promising. Might it happen? Yes, it might. It could be a good display. But going out with realistic expectations will help you enjoy your night and not come home too disappointed if it doesn’t amount to much.

Now, where did I leave that Daily Express application form? I’m quite sure they’d like a balanced, considered article like this…?!