The Sun had just set when this elegant smoke ring appeared over the petrochemical complex northeast of the city of Antwerp, Belgium. Barely visible in the picture is the trail of smoke that marked the path to the chimney that produced the ring. The life-span of the ring was a minute at most. The picture (a cropped version) was taken at 8:32 pm on August 14, 2001, using a digital Olympus C-200 camera with zoom set at 200 mm. A second ring appeared in the same place two minutes later (see next image). A total of four pictures were taken that evening. The temperatures had been extremely high all day and there was very little wind.
[© Wim VAN UTRECHT/CAELESTIA]