Can these Lights be Confused with the Famous BMLs?
This is an image of some city lights in Catawba Valley, Burke County, NC. Taken from the Highway 181 Brown Mountain Lights Overlook, approximately 16 miles northwest of Morganton. Looking southeast (140 azimuth) over the top of Brown Mountain. City lights include those of eastern Morganton, Drexel, and Valdese.
Selected individual lights are currently being identified by line-of-sight azimuth measurments, daytime and nighttime photography with teleophoto lenses (including a 1,900mm telescope), and follow up site visits for confirmation.
The single light above the skyline is a flashing white light atop a communication tower on High Peak (20 miles from camera, coordinates: 35.72280 N, 81.60810 W), 2.3 miles south of Drexel.
The six bright colored lights on the skyline (sloping line near left edge of image) are house lights on Rocky Road at 138.5-139.5 azimuth (21 miles from camera, coordinates: 35.71891 N, 81.58601 W), 2.0 miles southwest of Valdese.
Brown Mountain occupies the dark foreground while the South Mountains form the skyline ridges.
Image Info: Canon EOS Rebel T3i digital SLR camera with 420 mm telephoto lens, ISO 800, f/8, 20-second exposure, taken at 7:19 pm on 9Nov12 by Ed Speer.
Why do the lights look like they are out of focus? Because they are out of focus! It turns out its nearly impossible to capture well-focused images of the distant lights. First, camera shake during the long time exposures blurr the images, but long time exposures are needed to capture features of the landscape like skylines and ridge lines. Second, rising heat waves from the ground cause the lights to flicker, twinkle, undulate, and even change color due to the refraction by air currents of differing densities (as in mirages). The greater the magnification of the camera lens, the longer time exposure that is necessary and the greater the chance of blurry images due to camera shake and air refractions.
ReplyDeleteThus identifying individual lights is best done by observing its location and position relative to adjacent lights or lankmarks. Patterns of adjacent lights are often the most diagnostic, such as the vertical alignment of lights on a communication tower, a cluster of tower lights atop a hill, or a close-spaced line of lights on a skyline ridge like the houses south of Valdese.