Re Kiddush Levana on Mars: Mars has two moons, Phobos and Deimos. Both are much smaller than Earth’s moon .but closer. Phobos ‘s orbital period is about 7.6 hours and Deimos, being further away, has a period of a little more that 30 hrs, (our moon has an orbital period of 29 days) Which one would be used to calculate the month? Mars’ own year is 637 days and a Mars day is just a few minutes longer than ours. so do the math. Mars year is about 15,300 hours divided by 30 hrs (using Deimos) = 510 months in a Martian year. That should keep you busy.