So, first things first – I have absolutely no idea how in the universe this particular nebula got its name. It bears absolutely no resemblance to the novel by Tolstoy (except being ridiculously huge, hur hur), and I just can’t see how the boffins at the Midcourse Space Experiment managed to see a dove on one side and a skull on the other. Oh wait, they were imaging it in infra-red, which is pretty bloody useless for visual spectrum imagers like me!
I prefer to refer to it by its New General Catalogue number – NGC 6357. It removes confusion on what you’re actually meant to see, apart from a cool-looking nebula.
Interesting fact – at centre frame of this picture is star cluster Pismis 24, which contains some of the most massive stars known to science.
This was a 10-hour composite image – 5 hours hydrogen-alpha, 2 hours luminance, 1 hour red, green and blue.