This picture is simply spectacular, but there is one flaw. The curl on her forehead has far too much volume. Thin the top-left part of the curl and it should be perfect. Please do not be embarrassed by this mistake, I have judged many "Princess Luna" art pieces here and this flaw is extremely common.
This is perhaps one of the most fantastic renditions I have ever seen! The line work is so highly refined and extremely fluid! The character design is absolutely perfect and the body placement is just done perfectly! I also really love your amazing use of lighting and shading to greatly enhance the depth of this piece, adding another dimension of artistic beauty! Every element of this comes together gorgeously and it is a stunning piece of art! This is truly magnificent and I would really love to see more in the near future! Amazing work! Kind regards, Princess Luna