Celestia's adopting Philomena came as a bit of a surprise to Luna, and she took a while to get used to the firebird.The initial idea for the scene was having Celestia comforting a scared Luna, but what was scaring her went through a few different options, starting with just a moth, before I settled on using Philomena. I drew Philomena as an adult rather than a chick just because I found the adult phoenix easier to draw and place in the scene.EDIT: I've put Luna's muzzle back to a more traditional style, rather than the design I originally used. I had done it differently way as an experiment just to see what it would look like, but it didn't turn out as I had hoped.EDIT 2: Moved Philomena's head. I hadn't anticipated quite how hard it would be to see it when I had the idea. This should reduce further confusion. Background image by Spotted on Equestria Daily