Ray-tracing analyses show that the NZ effect distorted the relative positions of Jupiter and the Moon in such a way that the looked-for fingerprint of the 1597 conjunction occurred almost 2 h after the true conjunction. The quoted direction for the apparent Moon-Jupiter conjunction is then found to be accurate to within 1°. This delay of the apparent conjunction largely explains the error of 29° in their longitude determination. The truthfulness of the observations brackening the first recording of the NZ effect, debated for four centuries, now appears to be beyond doubt.