Sighting in Châteaudun, February 18, 1980

Several people watched an unusual light from the courtyard of a house. It was surrounded by a misty halo. A whitish ball of light hung motionless near a second object shaped like a crescent moon. This went on for several minutes. The phenomenon then moved from right to left and up and down for about twenty minutes, before travelling away at high speed toward the northwest. The witnesses described it as roughly three times larger than the neighbouring stars, and brighter. It faded gradually as it moved off. No sound was heard. No other witness account was collected, but a few days later the local press mentioned an "earthshine" sighting, the ashen glow that accompanies a new moon.

GEIPAN checked a sky chart and favoured an astronomical origin. New moon had been on 16 February, so only a thin crescent was visible, and it was up until 21:02 before dropping below the horizon. Venus shone just above it. The main witness, who made the observation around 9 p.m. or slightly earlier, therefore saw the Moon with earthshine and Venus above it. The gendarmes, observing at 21:15, saw only Venus before it set too, the Moon having already gone about twelve minutes earlier. The rapid movements reported were probably exaggerated without the witnesses realising it, because of the nearness of the horizon and possibly an autokinetic effect, the impression of movement that arises when staring intensely at a light. Conclusion: observation of the Moon and Venus, case classified A.