SUN_SET_RISE_PRECISION=15# n_grid_points; higher is more precise but very costly; astropy defaults to 150, 15 seems to cause errors of typically one minute
SUN_SET_RISE_PRECISION=30# n_grid_points; higher is more precise but very costly; astropy defaults to 150, errors now can be in the minutes, increase if this is not good enough
@lru_cache(maxsize=256,typed=False)# does not like lists, so use tuples to allow caching