BOIS-GUILLAUME (76) 12.08.2012

On the night of 11–12 August 2012 around 00:25, a witness saw an object below Cassiopeia moving west at apparently low altitude. As it neared the building's roof it became more visible: a dark form with white luminous circles at 3 extremities forming a triangle. It moved silently over the roof and out of sight. Only 1 account was collected. Viewed separately, the white lights strongly suggest windborne sky lanterns: - Their direction matched that evening's wind (see Infoclimat). - An August weekend night favored festive lantern releases. - The witness described a less familiar lantern feature: viewed from below, the burner forms a dark central disk, leaving a bright rim. This matches the description of luminous circle perimeters and centers nearly as dark as the object (see accompanying video). The witness called it triangular but specified very little contrast between its dark surface and the night sky, with a circle at each of the 3 corners. GEIPAN considers a false perception of shape very likely, a familiar misidentification in lantern-related triangle and polygon reports. The visual system fills the space between separate lights with a familiar imagined form (see Gestalt psychology). Once formed, that impression can acquire thickness—the witness described broad, thick edges—because cylindrical lanterns themselves have vertical extent. GEIPAN classifies the case B: sky lanterns.