Sunset Series from Hidden Beach
December 31, 2005
Provided by: Wojtek Rychlik, Pikes Peak Photo
Summary authors & editors: Jim Foster; Wojtek Rychlik
The remarkable photo series above shows various stages of a sunset taken from Hidden Beach in northern California (40 miles or 64 km south of Oregon border) on July 20, 2005. Click on photo for a larger view. According to U.S. Naval Observatory, sunset on this date actually occurred at Hidden Beach at 20:45, but the upper rim of the Sun was fully visible several minutes later due to atmospheric refraction, which is also responsible for the distortion of the Sun's shape. A mock green flash can be easily detected at 8:42:32 and at 43:42. Whereas the green flash occurs because of atmospheric dispersion (see links below for more details), a mock mirage results from a temperature inversion. Essentially, layering of relatively warm air atop a cooler layer, just above the sea surface, causes abnormal atmospheric refraction. This produces a mirage, causing the top of the Sun to appear detached and flash green. The uppermost tip of the Sun is also detached beginning at 45:02. Note the sharp brightness change in the photos. These shots were made initially using ISO 100 (f/32 and 1/750s), but for the last photo ISO 1,600 (f/8 and 1/750s) was used -- a 1,365-fold change of exposure within less than 7 minutes. To close out the year, a few other sunset photos are included as related links.
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