Create an image of a celestial being riding a comet through a sky filled with mystical creatures and constellations, blending elements of astronomy, fantasy, and mythology in a breathtaking cosmic panorama.

Imagine a celestial being with glowing wings that shimmer silver in the light, riding a bright green comet rocketing through a sky filled with mystical creatures. Not only are there mythical beasts like dragons and unicorns soaring amid the constellations, but also unknown creatures from far-off fantasies, each more marvelous than the last. Infuse elements of astronomy throughout this scene, with multitudes of stars scattering light across the canvas of the sky, renowned constellations gleaming prominently, and even nebulae and galaxies decorating the far reaches of the scene. The image we are envisioning is a breathtaking cosmic panorama, where fantasy meets astronomy in a harmonious blend of mythology, evoking a sense of wonder and awe.