Sighting in Le Thor, December 17, 2016

On a Saturday evening, at around 8:45 pm, a witness noticed a very bright orange-red light moving silently across the sky. It vanished quickly, but the witness had time to take a photograph. They were the only person to come forward, and their report came late, more than a month after the event.

The investigation concluded that the witness had probably seen a Thai lantern. Their description of what they saw with the naked eye fits such an object, and a weekend evening is a likely time for a lantern release at a celebration. The wind recorded on Infoclimat was light, consistent with the light's slow change of position. The strangeness the witness perceived stems mainly from the photo, which shows an orange arabesque. This is a classic camera-shake effect: the exposure lasted 4 seconds and the witness moved the camera before it ended. The picture shows a strong central bright point, corresponding to the steady phase, followed by a trail whose intensity drops as the sweeping speed increases. The other bright points in the photo, probably stars, are much fainter and only registered on the sensor during the steady phase, so they show no trail. The light's disappearance right after the photo was a coincidence: the lantern went out. The witness probably also spent a moment looking at the photo on the viewfinder screen before looking at the sky again, so the simultaneity may have been less sharp than it seemed.

GEIPAN therefore classified the case as B: Thai lantern.