One of our cameras at the Kjell Henriksen Observatory (KHO) recorded a fascinating phenomenon on December 21st. Professor II at UNIS, Pål Brekke, points out that it looks like the Twilight Effect caused by a rocket. This happens when the rocket reaches the mesosphere at 80-90 km altitude. At this point, the propeller exhaust of the rocket is free to expand in the less dense atmosphere. The vapour trail condenses, freezes, and expands fast. The high-altitude sunlight shines on the exhaust, creating a stunning view from the ground.
Professor in Optics and Atmospheric Research and Head of KHO, Fred Sigernes, explains that an all-sky camera records a fish-eye view of the sky. The instruments are designed to do real-time low-light monitoring of the sky. The phenomenon was simultaneously detected by the University of Oslo (UiO) all-sky camera in Ny Ålesund. Camera operator Bjørn Lybekk (UiO) was the first to detect the event and alert KHO.