This 4K video captures the somewhat elusive and unusual form of aurora that has come to be known as Steve, or STEVE -- for Strong Thermal Emission Velocity Enhancement. This was May 6, 2018 from southern Alberta, indeed from my yard in rural Alberta. The time was from 11 pm to midnight.
This night the main aurora to the north was weak and largely inactive as we saw it, but had been very active earlier in the night from more northern locations. Churchill, Manitoba far to the east and north of me had a fabulous display about an hour before I shot Steve, despite the bright twilight sky at their latitude at this time of year.
STEVE usually appears after a major outburst or substorm, and appears as glowing white or grey arc across the sky. The camera records the pink colour, and the brief appearance of slowly moving green fingers in a "picket fence" formation.
The origin and nature of STEVE is a subject of investigation, as is the aurora in general.
Evidence seems to point to STEVE being a hot flowing current of glowing gas, and is not not from raining electrons as are normal auroras. At the moment, amateur photos and videos are proving useful to STEVE researchers.
For more information about STEVE see the Aurorasaurus Blog at blog.aurorasaurus.org/?p=557
The video incorporates a time-lapse clip taken over 48 minutes, started with STEVE well established, and ended after he faded. It is made of 180 15-second exposures with the Sigma 8mm fish-eye lens on a Canon 6D MkII at ISO 6400. It show the entire sky with south at bottom.
STEVE typically lasts no more than an hour.
The majority of the video is made of real-time videos, shot in compressed 4K at 24 frames per second, with the new Sony a7III mirrorless camera and Canon 24mm lens at f/1.4. The Sony allows a shutter speed as low as 1/4 of a second when taking videos, which is what I used here. Even so, ISO speed was 25,600 for most clips, while the final clip of STEVE overhead was at ISO 51,200, so it is a tad noisy! But it shows the subtle motion in the arc that the eye could not see.
I look forward to shooting more auroras in real-time with the Sony.
A new video -- Aurora Reflections -- with more real-time clips from the Sony shot September 8, 2018 in Yellowknife is elsewhere on my channel.
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