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star shaped light pillar
Photographed at Ath, Belgium, this is undoubtedly one of the most remarkable displays of pillar-shaped reflections in cirriform clouds ever captured on film. The photo shown here was taken by amateur astronomer JoŽl BAVAIS on November 20, 2006. At about 4:30 that morning JoŽl went outside because he couldn't sleep. The night before, the Leonid shower had reached its maximum and perhaps he would be fortunate enough to catch a glimpse of one or two meteors. To his amazement he noticed that, instead of meteors, there was this unusual star-shaped collection of light pillars near zenith (elevation, as gleaned from the position of the stars, was approximately 85°). JoŽl placed his camera (a Canon EOS 300D) on the garden table, pointed it straight up, and managed to get a few shots of the display before it faded away.

The brightest reflections in the shot were caused by spotlights illuminating a church tower 1,2 km (0.7 miles) distant from the garden from which the photo was taken. An acquaintance of Mr. BAVAIS, meteorologist Fabian DEBAL, checked the weather data for the morning of November 20th and found that the temperature near the ground had been 5 to 6° Celsius. His verifications further showed that there were low clouds (stratocumulus) with temperatures just below zero at altitudes between 1,600 and 2,400 metres (5,249 and 7,874 feet) and high clouds (cirrus) with temperatures between -20 and -30° Celsius at altitudes between 6,500 and 7,000 metres (21,325 to 22,966 feet).This altitude matches the altitude of the reflections (6,858 metres or 22,500 feet) as calculated from the elevation of the pillars and the distance between the church tower and the camera.

Of particular interest is the "empty", circular area around the zenith which might evoke the impression of a dark disc with beams projecting in different directions.

[© JoŽl BAVAIS - photo shown with permission (more pictures by JoŽl BAVAIS can be found on www.levezlenez.net)]