This was a fantastic evening of aurora with some very intense short periods where the pink lower fringe was very visible to my naked eye and the curtains of rayed bands danced very rapidly across the sky. I was fortunate to be lucky with my timings this evening too, as I had literally just got to the site, set up my camera and taken the first test shots when the aurora burst into life for the first time in the evening. This first intense bout of activity happened at 21:57 UTC, with a strong band of aurora forming overhead and then a burst of rays erupting from the sky above us (Image 1). This band then shifted northwards (Image 2) and widened to form multiple rayed bands flickering across the sky and leaving a larger area of diffuse green overhead where it had started (Image 3).
This was closely followed by a second very intense burst in the northern sky. Images 4 to 6 were all taken within a 1-min period, which demonstrates how rapidly the structure and location of the aurora can change in the sky when it is intensely active like this. Additionally, this was a very dark and rather windy evening (so sadly the lake was not calm enough to get reflections), but it is clear how a bright aurora can illuminate the landscape even in the very short 3–4 second exposures in these images.
The third distinct period of high activity happened at 22:21 UTC and occurred much to the north of my location at less than 45 degrees. A dancing rayed band with a pink lower edge was visible (Image 7) during this time, which shifted southwards towards us and dissipated on the way. A similar scenario unfolded at 22:46, with another intense band forming in the north and then shifting southwards and expanding/dissipating over the following minutes (Images 8 and 9). Strong activity continued to the north for the remainder of the time that we were out (until 23:25). Although much of the northern half of the sky (from overhead to the horizon) was weak green, the area from 50 degrees to the far northern horizon had distinct rayed bands of much stronger activity, with clusters of defined rays forming intermittently (Images 10 to 12).
The readout from the Leirvogur magnetometer on this evening is shown in Image 13, with a black rectangle marking the timespan when I made my observations. The intense activity shown in the images correlates reasonably well with the strong dips in the magnetometer data.
Image 1. 21:58 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 5 sec. Looking east.
Image 2. 22:02 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 10 sec. Looking north-west.
Image 3. 22:07 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 20 sec. Looking north-west.
Image 4. 22:09 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 3.6 sec. Looking north-west.
Image 5. 22:10 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 3.2 sec. Looking north-west.
Image 6. 22:10 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 4.3 sec. Looking north-west.
Image 7. 22:22 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 11 sec. Looking north-west.
Image 8. 22:47 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 6.5 sec. Looking north-west.
Image 9. 22:48 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 6.7 sec. Looking north-west.
Image 10. 22:54 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 14 sec. Looking north.
Image 11. 23:15 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 21 sec. Looking north.
Image 12. 23:20 UTC. Taken at: ISO = 1600, f/2.8 @ 14 mm, exposure = 28 sec. Looking north.
Image 13. Magnetometer data from the Leirvogur magnetometer (from flux.phys.uit.no) with a box showing the time overlap with the images taken.
