Yeah, delete would be good at the least. Granted, nothing on the internet really ever goes away, (or at least that's what They tell you) but at the same time, having typos out there for the world to see seems like it could be avoided.
I like it ^^ It's a wonderful drawing and you really bring out the transluscence-ness of Luna's magical aura.
I only have a few critiques (From my over-analytical nature): Rarity's posing looks... awkward and forced, and I would think someone so savvy as you and stylish as rarity would have transitional makeup for the nighttime
Also, I dislike Twilight's expression... It's just... Odd..
But I can see the work you put into the other three, really nice Job ^^
I've always preferred night over day, simply because of the stars. I love the warmth that day brings too, mind you, but it's just the cool gales that lightly flutter throughout the trees and wind over the grassy hills, combine with the endless expanse of stars overhead that make night just... beautiful.
I always thought it might be a good idea for somepony to show Princess Luna that they really do appreciate her nights. No one would want a repeat of that late unpleasantness... not that Luna would do that again, of course, but why take a chance?