Tuesday, November 27, 2012

Catawba Valley City Lights November 26, 2012

Compare this image with the previous one taken on November 9, 2012---both taken from the Highway 181 BML overlook with the same camera and lens.  The photos were taken 17 days apart, but show the same lights in the same colors, positions, and patterns.  There has been no significant movement or changes in 95% of the lights---however close inspection of the two images does show a few changes, which probably relate to moving vehicle lights and/or flashing tower or advertising lights.
As in the November 9, 2012 photo, the isolated single white light above the skyline is a communication tower on High Peak, while the sloping row of close-spaced lights on the skyline ridge near the left edge of the image are house lights on Rocky Road south of Valdese.  From right to left, the city lights of east Morganton, Drexel and Valdese are visible.
Canon EOS Rebel T3i DSLR camera with a 420-mm telephoto lens and ten-second exposure at f/8 and ISO 800.

1 comment:

  1. Many people report seeing moving lights---so what's up? Certainly some of the distant electric lights do move---such as cars, trains, and airplanes. Nearly 100,000 people live in the Catawba and Yadkin Valleys within 50 miles of the 181 BML overlook, so vehicles are to be expected. In fact, at least two lighted airports lie just below the ridge line to the east of Brown Mountain and night time photography often reveals airplanes in the sky.

    While the majority of the city lights do not change position, an optical illusion of movement can be caused by refractions due to rising heat currents. Even after dark, heat radiates from the ground upward to the sky and this is most active in the first half of the night---the same time when most people are viewing the lights. The refracted lights are seen to wobble, twinkle, undalate, fade in & out, and even change colors---giving the false appearance of movement. Observing individual lights thru a tripod-mounted camera or telescope lens, or photographing the same area weeks later, confirms the lack of movement.