Large luminous disc in the Gironde night mistaken for the moon

Summary

On the night of 15 August 2007, a driver in the Gironde region spotted a large luminous disc that they initially took for the moon. Astronomical analysis ruled this out: the waning crescent moon had set over an hour earlier. Jupiter, however, was very close to the reported direction, at magnitude –2, though it is surprising it was perceived as moon-sized.

The weather indicated overcast skies with intermittent rain. Two hypotheses emerged: a halo effect from low clouds around Jupiter, similar to a winter sun halo, or a farm vehicle headlight on a hillside magnified by post-rain fog. With insufficient data to confirm either, GEIPAN classified the case as C.