Navigation lights on aeroplanes are used to signal the craft’s location and heading. They are the primary focus in Terence Chang’s wonderful long exposure photos. During a period from July 2008 and April 2010, Chang went to San Francisco International Airport (SFO) to photograph air traffic. What looks like handmade light paintings are the trails made by the navigation lights on the aeroplanes as they took off and landed from the airport. See a few of Chang’s long exposure shots after the jump.