In May , 2011 I went to Yunnan province for travelling.It was the time when I went to small minority tribe village.I took some pic.and I came back to my home Seoul, Korea.I organized my pics which were taken for Yunam travelling.and I found that pic. I tried to enlarge my pic. and that point shaped like triangle.I've been wondering since finding that pic.I believe that the point is not dust on lens.and as you can see distance was too far to see like kite or any plane.Please find my pic out and reply your viewthank you for helping me.