Originally Posted by
Ivan J. Eberle
I think I can field this one with some authority since I worked beside astronomers at an optical telescope observatory for a dozen years. Stars remain pinpoint for about 2-4 seconds without any tracking, depending on magnification. So that's most likely a long telescope tracking exposure (tip off is the deep red hydrogen response.) And it's a composite image to get the tree. Common enough cheat, that to BS about it is pretty cheesy. Incidentally, it was astronomers who invented image-stacking, to get around noise issues with early noisy piezo-cooled digital sensors (they'd been using liquid nitrogen cooled ones, prior, to keep circuit noise down to manageable levels). It's so easy to stack exposures these days, that this might be dozens of images of the stars, too-- especially if shot with a relatively noisy DSLR tracking through or piggybacked upon a telescope.