LIAS (32) 19.08.2023

After installing an automated night-sky imaging system on the terrace of his home in Lias (32) for the night of 19–20 August 2023, a witness found 2 UAPs in the recordings. They looked alike and followed similar winding, erratic paths. Substantiation was strong despite no direct visual observation. The images were exhaustively analyzed, with precise timing established from file metadata (see investigation report). GEIPAN defines substantiation as the amount of reliable, objectively established information collected for an account. Several hypotheses were assessed: - Bats might follow such paths, but the combined calculated altitude and speed were incompatible: too high and too slow. - Two nocturnal birds, specifically eagle-owls with a juvenile learning from an adult, were likewise inconsistent with the altitude in relation to flying speed. The observation period was also too late. - Two insects near the lens were considered but rejected. They would have needed to be more than 3.50 m away and to fly far too slowly to cover the path in nearly 30 minutes. - Two LED-lit balloons fitted most of the analysis, especially slow sinusoidal motion consistent with light winds aloft and confirmed wind shear. GEIPAN's Météo-France expert confirmed these weather findings. More specifically, supporting features were a common whitish balloon color; overall movement southeastward with the wind; erratic motion caused by wind shear between 750 and 875 m; calculated speeds matching winds estimated at those heights from Météo-France data; and weekend timing favorable for festive illuminated balloons. The actual UAP shapes could not be determined because each photograph's exposure time distorted them. The balloon hypothesis reduced the sighting's strangeness. GEIPAN nevertheless noted that the absence of direct visual witnesses would normally make it ineligible for investigation. It studied this case because both GEIPAN and the witness found it curious and because of the methodological interest. The case was classified B: 2 probable LED balloons carried by winds aloft.