while scrolling through the public library, I was surprised that there was no Open-Source version of the Moon Phase indicator. All moon phase indicators in the public library were either protected or not exactly what I was looking for. There is a built-in "Moon Phase" indicator, but even for this one, we can't access its source code.
Therefore, I started searching for an algorithm that I could implement into PineScript.
So here we go, an Open-Source Moon Phase indicator. It comes with the option to color the background based on the recent moon. Compared to the built-in indicator, the moon is slightly shifted, because it is centered on the candle and not plotted between two candles like the built-in indicator is doing it.
Feel free to use the indicator for your analysis or build on top of it in an open-source fashion.