Flaring activities at the BASF petrochemical complex north of Antwerp, Belgium, generated this light pillar in the evening of December 19, 2009 (photograph taken from the city centre, 19.6 km or 12.2 miles ESE of the complex).
The pillar was visible between 06:10 p.m. and 06:55 p.m. This photo was taken at 06:23 p.m. The altitude of the reflective ice-crystal layer was found to be between 1 and 1.4 km (roughly between 3,300 and 4,600 feet).
Later that night, between 00:00 and 01:25 a.m., a pillar appeared in an ice cloud at a much higher altitude (see images OP-PH-25 and OP-PH-26].
Camera: Sony DSLR A100; exposure time: 3.2 sec.; aperture: 5.6; ISO setting: 800; focal length: 50 mm.
Also compare with OP-PL-09 and OP-PL-10, which show a similar pillar caused by the same combustion flame and photographed from the same location two years earlier.
[© Wim VAN UTRECHT/CAELESTIA]