Sighting in Toutlemonde, October 31, 2017

Shortly before 1 a.m., under a clear sky, a witness was looking at the stars toward the east; the western sky was harder to see because of moonlight and the glow of the nearby town. Scanning the horizon, they noticed a fairly bright white light to the east-southeast, with blue and red flashes. Five minutes later it had moved little or not at all. The witness then checked an astronomy app on their smartphone, which showed nothing listed at that spot.

As the observation continued, the witness saw the point rise vertically and, from time to time, make short, rapid, jerky movements in a straight line. The photos and videos they tried to take were of little use because the light was too faint. Twenty-five minutes later the point was still there, clearly higher than at the start, and the colored flashing had not stopped. Its white light looked much stronger than that of the stars. Only one witness account was collected.

The investigation reconstructed the sky with mapping software: in the direction the witness indicated, at an azimuth close to 120°, Sirius lay very low above the horizon and climbed slowly during the night. In the witness's photo, the position of the light relative to the neighboring stars matched that of Sirius. The star's absence from the app was probably due to poor calibration or a slight offset. The color changes come from atmospheric turbulence, the jerky movements from a known perceptual effect called the autokinetic effect, and the slow climb from the Earth's rotation. GEIPAN classified the case as A: the witness had observed Sirius.