Retool of This: emkay-mlp.deviantart.com/art/N…
Feel free to use, but only with credit linked back to here!
EDIT: Yes, the star is red, and that is a color in the Solar Empire emblem. But lots of opposing countries have emblems with similar colors, and they may even be for different reasons.
My idea is that the colors I chose hold symbolic significance to the members of the revolution. For example:
Midnight blue and the horned moon may represent the night sky, the eternal night that Luna's followers seek.
The lighter blue/grey color, as well as the wings, may represent the hopes of the rebellion to overcome the tyranny that is the sun and to finally live in the peace of Lunar rule.
And last of all, the red star may represent the blazing fury of the rebels against the evil of Celestia's rule, and the star's placement on the horn may represent the magic and the power that their cause will give them to rise above and end her reign in Equestria.