Good question.  I'm not sure of the process you are describing but if it is just a method of projecting a photo onto a plane instead of view the photo itself, I'd say it is not allowable.  But, if you are projecting a Bryce created gel or whatever I'd say ok.  The criteria is, "is  the sky (or fake sky in this case) a 3d creation and not a photo of what nature has already done."   Did that help?

If you have a process that you think should be legal, then submit it with an explanation as WIP here and let the forum pass judgement before you upload to challenge.  I think that would be fair.  You may be pushing the envelop of creativity that needs to be shared.  Good luck.  I'm anxious to see what you have to offer.

I just noticed your link.  Definitely not a photo, but looks more spacey than atmosphere as it stands in your image.  If you can incorporate it into a scene to convince the voters it is a sky and not a nebula, go for it.  It is their vote that counts.

Who's "Orbital"? 

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