The article talks a bit about it. It's a composite image, and he uses special lenses that capture non-visible light.
And when it's a composite image, you can capture the appropriate amount of light for each part of the photo. A single photo needs to compromise, think of how a photo of the moon never has stars in it, because if the exposure is long enough to pick up starlight then the moon is far too bright. The winning photo here is 60 photos stitched together, so each part of the final image is just right.
I think you can argue something like this winning image is as much photoshop as it is photograph, but it's still really cool.