Sighting in Annecy, October 13, 2018

A witness was at a playground when a bright flash in the sky caught their attention. They described an object that seemed to consist of two reflections of the sun on either side of a central element. They immediately took photos with their mobile phone. No other witness account was collected.

The investigation could not properly characterise the object. The photographs contain no reference points, so the object cannot be placed in space, any movement cannot be identified, and neither its distance nor its size can be estimated. It could just as well have been very distant and large, as the witness suspected, or much closer and smaller. Its shape remains blurry, because the lens and sensor of the device (an iPhone 4s) produce heavy background noise and are poorly suited to small, distant subjects, which also ruled out a depth-of-field study. In addition, the object had an angular size under 0.5° and stood out against a uniform blue sky, which explains why the witness struggled to judge its shape and movements.

The witness suggested it might have been a stratospheric balloon. Searches on the Internet and with the CNES department dedicated to balloons produced nothing. The sizes and distances estimated from the photos with the IPACO software could fit this hypothesis, but the other parameters are missing or too imprecise to confirm it. For lack of reliable data, the GEIPAN classified the case as C.