Board Thread:General Mod Discussion/@comment-25565811-20170120101550/@comment-25101089-20170120143308

It is true! The moon turns red on some nights, and on those nights, invasions have a greater chance of spawning.

The way it calculates lunar eclipses works by Shire Reckoning. The 'day' number (which is the number of Shire Reckoning days elapsed since the start date of Bilbo's birthday) is used: if the day is a multiple of 8 (a full moon), and dividing the day by 32 yields a remainder of 24, it's a lunar eclipse. This means that eclipses occur every 32 ingame days (every 4 full moons), starting on the 24th day (the fourth full moon to appear, including the full moon on the very first day). This is more common than in real life, but not loads more common. (Or if you choose to interpret the 8-day moon phase cycle as a month, instead of the actual calendar months, it's pretty much accurate to real life.)

I also linked moon phases to the 'day' number, instead of using the actual world time as is done in the vanilla game, which is more helpful if you want to use commands to change these things.

Having said that, maybe it would be better to have the moon phase cycle last 24 or 32 calendar days instead of 8, making 'moon-months' and 'calendar-months' correspond much more closely, as they should? But that would make lunar eclipses much rarer...