May 17, 2008
While watching the Sun get ready to set for one of the last times in 2007 (December 27), I was lucky enough to observe an upper and lower Sun pillar. The photo above was taken south of Peterborough, Ontario, Canada. I first noticed a pillar form above the Sun, which was hidden behind the band of clouds near the horizon, but then I could see that a more unusual secondary pillar was developing below the solar disk. In affect, the clouds are forming a false horizon. Typically, the actual horizon helps block the bright solar disk as it sets or rises, and thus allows the "pillar" to be seen from our earthly vantage point. Horizontally stacked plates of ice crystals high in the Earth's atmosphere reflect the Sun's rays to form pillars. However, these crystals aren’t always just above the Sun's orientation to the observer. This “double pillar” effect lasted only a few moments as the clouds appeared to swallow the Sun before it even reached the real horizon. I’ve observed this phenomenon before, and the secondary pillar (below the Sun) is never as long as the primary (upper) pillar.
Photo details: Canon XTi Digital SLR camera, 200 ISO, 1/250 shutter speed, f/9.0, 17-70 mm Sigma lens at 70 mm.