Giant blue rays above red auroras
Taken by Nicolas_Rossetto on September 25, 2023 @
Jouhe, France
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Details:
During the night from 24th to 25th September 2023, when two burst of red auroras occurred over Europe and was visible with unaided eyes from France.
At the second appearance, about 20 minutes after the maximum that took place near 3:57 AM local time, using the pictures and the time lapse created with, I managed to take a sight of a long blue column, rising high in the sky (about 60 to 65° above the horizon from my position).
This blue column seems to match with what is called Giant Blue Rays, as I discovered it while reading the « Polarlight section » of the German forum Meteoros where the phenomenon has been pictured at the same time and the week earlier by M. Theusner and then analysed (physical origin, height, ...).
Here is then an overview from my pictures, with various rendering, in order to make the phenomenon more visible, along with a geometric simulation and distance measurement with a map.
On my pictures, with adequate processing, the blue rays are visible from 4:09 to at least 4h32 (I don't have the raws any more after this time and the processing result from the original RGB standard processing matching time after 4h32 is debased).
In standard RBG processing, the sight is weak, but with only blue channel processing, the rays are more visible and with further unsharp mask processing the rays' height can be estimated.
Giving my position and the supposed position of the base of the column (1300 km from my camera, base on the maximum of activity measured by ROTI instruments during the first outburst of the night, 1° north to Denmark) the top of the column, rising at 60 to 65° high, give something like 4000 km high !
This need to be confirmed/informed with other sighting, from other places.
This is a call to other auroras watcher that may have captured this event (maximum of sighting near 4:20 AM local time, 2:20 UT) and might be able to make the blue rays visible on their pictures, in order to measure its height.
Details for single images used for this mosaic:
Canon EOS 6D
Samyang 8mm, f/3,5, ISO1250, 25''.
Near 4h20 AM
Details for image processing:
Top right: RGB processing, with level stretching on each channel separately.
Bottom right: Blue channel rendering.
Bottom left: Black and white colour mixing processing, with red and green set to zero
Top left: Stack of 7 pictures from blue rendering, with unsharp masked applied, in order to catch the extension of the rays. We can then take a sight of a secondary ray, on the left of the first.
Photographer's website:
https://www.flickr.com/photos/gaukouphoto/
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