This image has been captured on September 12, 2024 at 23:00 CEST from the ridge between mounts Segla and Hesten. I got the Sun's height from Stellarium to be -14°30' for the given time.
Blue Aurorae are a somewhat special phenomenon, since they only can occur if ionized Nitrogen molecules are involved. The production of N2+ in the thermosphere requires excitation by hard UV from sunlight irradiation ("sunlit aurora"). That means, the lower border of these blue colors marks the earth's shadow.
Blue aurorae can reach enormous altitudes above 500 km (Starlinks satellites currently operate at ~540 ... 570 km). There are reports of "Giant Blue Rays" reaching several thousand kilometers into the exosphere. It is assumed, the ions are hurled into those extreme high altitudes during strong geomagnetic impacts.
That night, a G3 storm went off, with Kp index reaching 7 and Bz -24 nT (ACE) around 6 pm UTC (that's about 8 pm CEST, so 3 hours before this image was taken). Documentation of observations in Germany:
https://www.polarlicht-archiv.de/events/date/1/#2024-09-12German meteorologist Michael Theusner proved the occurence of a Giant Blue Ray that night by using parallactic methods (also listed in the collection above):
https://www.polarlicht-archiv.de/files/images/2024-09-12/2024-09-12_michaeltheusner_7.jpg
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