Dear Twilight Sparkle,
While I am pleased to note your enthusiasm for the night sky and your interest in star arrangements, I must admit that this is perhaps one of the more 'odd' requests I have had, and I'm actually somewhat relieved that you changed your mind. Mostly because I am suspicious of why you've made it.
In the future, just request a falling star for whatever clandestine meeting like everypony else, won't you? At least that way I don't need to design a new constellation and deal with ponies asking me why a star-squirrel is holding up the moon like a giant nut.
More importantly, do you really want to be responsible for the potential creation of a new star-beast?
Your friend,
Princess Luna.