Tested in Suunto Traverse
This app calculate moon age in days:
/* While in sport mode do this once per second */ MoonMonth = 29.53; FirstNewMoonDayIn2000 = 6; DaysFrom2000 = SUUNTO_DAYS_AFTER_1_1_2000 + (SUUNTO_TIME/86400); DaysFromNewMoon = DaysFrom2000 - FirstNewMoonDayIn2000; MoonAge = Suunto.mod(DaysFromNewMoon/MoonMonth,1) * MoonMonth; postfix = "Days"; RESULT = MoonAge;