Interesting proposition: adding the moon phases to the clock. Adding clock faces is very easy, however integrating one module into the other (a clock into the weather module, or a partial weather query inside the clock module), now you’re working to make a third beast of a module. A possible solution might be to have the clock module listen to broadcasts from the weather module and adjust its face accordingly.
A possible working method:
configure the clock to have an analog face (with a default face)
configure the clock to listen to weather broadcasts
configure the weather module to broadcast moon phases
if/when the clock receives such notification (hopefully only once a day), it will change its face to match and timing will be of importance here when the mirror first loads up - what if the weather module broadcasts before the clock is up and running?
Then there’s the question of, how detailed do you want it to be? Do you want a 28-day moon phase displayed? Or a simplified 8-stages version?
Something else to keep in mind, having an actual image will increase the payload of the module itself. Right now all of the analog faces are SVG files, which are rather small, and they can be scaled without losing resolution. You can’t easily do that with an actual picture. Either you are including very large images in case someone (like me) decides to have a screen with ONLY the clock on it, taking up the full screen, and still be able to scale it small for the “normal” folks. Personally my vote would be to use plain black and white SVG images. They’ll be small and easily scalable.
Anyway, that’s my 2 pesos.