Sighting in Olonne-sur-Mer, May 17, 2020

A witness saw a very unusual object in the sky at about 1 a.m. that lasted around ten seconds. It was triangular, moved at a steady speed with its flat face parallel to the ground, and had a white point of light at each corner. Its color seemed to blend into the sky behind it, or to slightly distort the sky's appearance. The lights shone about as brightly as an average star, and no noise was reported. The witness was the only person to report the sighting. The object traveled from north to south.

The investigation concluded that the witness most likely saw nine Thai lanterns. A Saturday-to-Sunday night in spring is a typical time for a lantern release at local or private celebrations. At that distance, lanterns look like simple points of light, and their shape cannot be made out. The Château d'Olonne weather station, 8 km from the observation site, recorded a wind of 8 km/h blowing from north to south at the time, which matches the speed and direction observed. The brightness, the lack of noise and the number of lights are also consistent with this explanation. White is not the most common color for lanterns, but it often appears in confirmed cases.

The triangular shape is explained by an illusion of form or contour, in which an observer links independent lights into a single object. The same effect can occur with an aircraft whose wings are hard to see. GEIPAN classified the case as B, probable observation of Thai lanterns.