I thought I had implemented #Meeus's Earth #nutation algorithm incorrectly, because it gives -3.808 for Δψ (nutation in longitude) instead of -3.788 for the example. So I checked my implementation carefully for errors. Found an error in the Moon's argument of longitude. Not enough to make a difference. Found an error in the coefficient table, but it was a coefficient used only in Δε (nutation in obliquity). So I figured it must be precision related, so I converted everything to use Python's decimal type, along with the sine and cosine implementations from https://docs.python.org/3/library/decimal.html . Same result. So either there's an error in the book, I'm somehow missing some error in the implementation, or the example actually uses the low-precision version of the algorithm that he gives. If it's this last, that would be annoying, because the high-precision version has a lot more room for mistakes.

Time to find someone else's implementation and compare the results.

Due to human-induced #climatechange, the number of high tide floods has been growing over the last decade. Research from #NASA now suggests that in the mid-2030s, this might reach a more dangerous high as the effect of the climate crisis combine with a peculiar lunar cycle called #nutation.

https://www.iflscience.com/environment/climate-change-and-a-lunar-wobble-raise-alarm-for-major-coastal-flooding-in-the-2030s/

#ClimateCrisis #Flooding