PARADOU (13) 04.09.2021

A witness reported an unexplained sky observation on 4 September 2021 at 01:13 and supplied photographs and video. The object appeared stationary in the photograph taken at that moment, while the video clearly showed it moving back and forth, disappearing and reappearing intermittently. GEIPAN considered the case well substantiated—the amount of reliable information collected—because a photograph and video could be analyzed despite the sole witness (see investigation report). Investigators concluded that it was very probably a luminous patch created by a ground-based Sky Rose searchlight on fairly low clouds. Supporting features were the circular shape typical of a projected spot, commonly associated white color, absence of sound and regular sweeping motion. Such observations usually occur under a uniform low or fairly low layer of stratocumulus or nimbostratus, dense enough to reflect a ground searchlight toward a witness. Here, weather data placed intermittent cloud at about 1,700/1,900 m. Good to very good horizontal visibility did not favor a visible beam between the ground and clouds, explaining why none was seen. The Friday-to-Saturday timing fitted a local celebration, event or nightclub display. The source states that nightclubs had not yet been allowed to reopen under Covid-19 restrictions; it therefore favored a private party or similar activity. No actual party could be confirmed, but the possibility remained plausible. The particular puzzle—the different shape in photograph and video—was attributed to an optical artifact from the smartphone's automatic settings in low light. A long exposure combined with the UAP's movement stretched an actually circular shape. This explanation is retained alongside the opening description of a stationary object in the photograph. GEIPAN classified the case A as a very probable luminous patch from a ground-based Sky Rose searchlight on fairly low cloud.