That white streak of light is a four wheel drive zooming past while I was taking a 30 second exposure. I figured the shot was ruined but, when I was finished shooting for the night and looking through the images, it turned out to be the best one. Not sure what the driver thought of me as he went past because I was standing off to the right of the tree with my torch and ‘painting’ the tree with light during the exposure so it wouldn’t come out pitch black. Turns out we both did some painting. The location was in the middle of nowhere - inland northern West Australia, miles from anywhere, which is where you want to be if you want a night sky without any light pollution. Apart from the vehicular kind.