You got this at exactly the right time of day to get the blue sky. You must have been using a 1.4 or 2x to get to 480mm. I'm impressed that the trees in the left foreground are in good focus. You were a long way away from them I would guess.
Good shooting, esp hand held with the long lens.
Great shot. I have never been able to get any sky color in my full moon shots. It seems when I get the exposure right to show detail in the moon, the sky goes black. I usually shoot with a about a stop and a half less exposure, which would certainly explain my black skys. In any event, Great shot. One of my favorites.