Sighting in Entremont-le-Vieux, August 12, 2018

During an evening of astronomical observation, two witnesses noticed two groups of luminous points moving silently across the sky. To the naked eye they looked like stars. Through a telescope, the lights appeared as handsome blue-grey balls moving quickly along a rising path. The sighting lasted about ten minutes, until the phenomena vanished. One of the witnesses tried to photograph them with a mobile phone, but the picture could not be used.

The GEIPAN analysis concluded that all the testimony fits a mistaken identification of two groups of Thai lanterns. Several points support this: the ball shape, which results from the distance of observation; a low to medium brightness similar to a twinkling star, since the candles flicker in the relative wind produced by the lanterns' motion; a white or bluish colour, which is possible for such lanterns although not the most common; the lack of any sound; an observation time of up to 15 minutes; and a straight, steady, slightly rising path, typical of lanterns drifting in calm or light wind. The summer season, the Saturday-to-Sunday night and the night-time hour are also especially favourable for lantern releases. Wind data at altitude, though not firmly established, remain consistent with ideal release conditions.

The investigation also suggested a possible launch point: a rental property surrounded by meadows, in a deep valley bordered by mountain ridges forming a corridor that would guide the lanterns. However, it could not be shown that a local celebration justifying their use took place at that date and time. GEIPAN classified the case as B: a probable misidentification of Thai lanterns.