590 frames, 21:48 to 04:48 (London time). Darkest sky 10.17 stops above black.
canon 2000D · night of 16 Aug 2026
Sky brightness of every frame (log₂: one stop is twice the light). Dusk and dawn are the slopes at each end; cloud shows as a bump. The star-trail stack uses only frames within 30% of the darkest 10 minutes, so twilight and cloud are left out of it. Left out is not thrown away: those frames still go into the videos.