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When NOAA announced that a weak CME was heading towards Earth with impact expected on April 15th I was far from excited, after all, a weak CME was hardly anything to get buzzing about, especially when all the recent auroras I had captured over the last year had been G2 to G4, after all, one does have standards you know (tongue in cheek). G1 geomagnetic storms are seldom impressive inland, you need to be at the north coast to get a better view of these, and since I wasn't planning to be there on the impact night I essentially paid very little interest to this set-up, after all we were well past the Spring Equinox and the R-M effect couldn't be relied upon so late in the season. Also factoring in light pollution and a waxing Moon I decided to focus instead on monitoring Blaze Star TCrB among other things.
April 15th arrived, however the CME didn't, all geomagnetic activity was suddenly dead, however it was cloudy anyway so like many I considered the event a bust. Then early on the 16th experts stated the CME was either too weak or missed Earth completely, then a few hours later it hit. The wind speed only just got above 340km/sec however the Bz stayed S all day, at once stage -10, I decided that this was slightly interesting but still nothing to get too worked up about, after all, NOAA only were going for G1 levels and another site stated active levels only. Besides, the forecast was dodgy, with a cold NWly flow there would be on and off rain and hail showers, however there would be clear breaks too.
Around sunset the Bz rose slightly to -3 however I gave it little thought. I was on facebook chat with Colleen Webb and Nigel McFarland, we discussed the clear gaps and Nigel went to the coast aurora hunting, however all expectations were low. Then before 23.00 Colleen got a clear break over her home in Portglenone and sent us an image of the aurora taken from our garden, with a hand held mobile phone!, the sky was purple with beams, I was shocked, surely the stats were not that good. At first I thought Colleen was winding me up, perhaps it was an image from another event, but she assured me she was deadly serious and was surprised too. Then Nigel posted an image from Benone Beach showing the same aurora complete with beams so this was actually happening.
I stepped outside and got treated to cloud and blowing rain, I checked radar which revealed a cell passing over, it would clear soon, ten minutes later the entire northern sky was clear with great transparency. With my eyes I saw absolutely nothing at all, but I needed to confirm if it was still there on camera. I knew that if I took time to drive out to find a good location then the aurora could subside, or the sky could cloud over, so instead I decided to put the drone up to take a look, this wasn't even meant to be a serious shoot, it was just a sky check. I set the drone to focus on infinity and kept it on manual, selected an appropriate white balance, a shutter speed of 8 sec's at F/2.8 and an ISO of 800 to keep noise at bay. I took an exposure to the N and there was a strange glow on the left of frame, so I panned the drone more to the NW and took another exposure and shockingly there was the aurora with tall but faint rays showing red colour shooting upwards from a low level green arc partially obscured by distant shower clouds. Feeling invigorated by the sight I began taking many exposures, each image showed the aurora getting better and better.
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Then the beams got brighter and taller, in this image purple pillars can be seen piercing through the 'W' shaped constellation of Cassiopeia. I alternated between taking images and going inside to inform Nigel and Colleen of what I was seeing, they were now clouded out, however I was still clear but for how much longer I didn't know so I kept shooting. I still couldn't see anything visually yet, I was actually surprised how well the beams were showing on the drone's camera, I could actually see them on the live FPV screen and that was with a fairly bright moon in the sky.
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Then at approximately 23.45 the aurora went into outburst, suddenly the beams intensified into a compact but bright well defined cluster with beautiful purple/red rays between Auriga and Perseus, now this was actually getting photogenic and I had to admit I felt quite a buzz as this was well beyond any of my expectations. To be honest I was fairly happy with this and watching it live on the drone screen really added to the thrill. There were random gusts of wind, at times the stars were trailed, but I just let the drone settle then took more images and the results were very encouraging, not bad at all for an aerial platform in wind with an 8 second exposure.
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I was standing outside Cookstown beside a neighborhood, I looked up from the screen and I was amazed to see slanted red beams with the naked eye rite above a close range streetlight!, this was my favourite image from the night with the purple-red beams slowly dancing across the sky over the Sperrins. That's the rear side of Slieve Gallion on the right with Moneyneany/Mullaghmore at centre. Then after ten minutes or so of a very pleasant outburst the beams faded from view just as quickly as they had appeared and the aurora was gone.
That sure was a nice unexpected surprise, especially as this could be my last aurora of the Spring season before Summer twilight brightens up the sky for the next few months. Before I landed the drone I took a glance half way up the eastern sky at Corona Borealis the Northern Crown, then focused my gaze to the SE corner below the star Epsilon. That blank region of sky was still blank, the Blaze Star hadn't stirred yet, but some night this year it will and we will have a naked eye Nova to enjoy. As the aurora season winds down I will be focusing my attention on storm chasing, NLCs, and aerial filming until dark skies return in August when attention will return once again to auroras and comets, and perhaps event a great comet. Thanks very much for reading.
Martin McKenna
