Well I think it's an awesome shot and totally meets the challenge (unless you try really hard not to see the sun!), I gave it a 10 and expected to see it much higher, around William's star trail photo. Beautiful color!
I'm saying that the subject of your photo is the parachutists, not "the sky" as per the challenge. One could argue that they are "in" the sky, but they are not the sky. My wife actually thinks that this does meet the challenge (and I can't argue that it's a great shot - very simple in composition, and great visual impact), but unfortunately for you she's not voting, I am. Therefore, I will be knocking off a mark or two for my perception of a DNMC. Sorry