BALLON SONDE — (REG) ILE-DE-FRANCE (IDF) 23.04.2020

During April 2020, GEIPAN received reports of 5 sightings in the Île-de-France region. They occurred in different municipalities on different dates, but all described the unusual presence of a light near Venus. The reports were registered as: BLANC-MESNIL (LE) (93) 15.04.2020 GONESSE (95) 15.04.2020 CERGY (95) 15.04.2020 GRISY-SUISNES (77) 19.04.2020 SAINT-PIERRE-DU-PERRAY (91) 23.04.2020 The attached investigation report deals particularly with the Saint-Pierre-du-Perray sighting of 23 April 2020, which was analyzed first. That evening, a resident was smoking a cigarette on his terrace and looking at the sky. He saw Venus and, a moment later, a second point of light almost as bright as Venus. This account had very little residual strangeness and good evidential support: there was only 1 witness, but the account was fairly precise and included a measurement of the UAP's position relative to a celestial object. The sighting proved to be a weather balloon misidentification. A radiosonde ascent launched from Trappes station (78) was under way at the time. The direction of observation, angular elevation and time at which the weather balloon burst matched the sighting perfectly. Météo-France confirmed that weather-balloon launches from Trappes had doubled during the exceptional circumstances of the public-health lockdown in April. This also explains the similar sightings in the Paris region in April 2020: Le Blanc-Mesnil and Gonesse on 15 April at 20:30, Cergy on 15 April at 20:50, and Grisy-Suisnes on 19 April at 21:10. The supplied radiosonde data show excellent agreement with both the observation directions and the times when the UAPs disappeared. All these reports are grouped into a single case classified A: weather balloon.