Estimating the value of the inclination angle of the lunar plane to the ecliptic plane

Abstract

Sky appears to our students as a vast volume surrounding the Earth. The most striking astronomical events that they can witness in the sky are lunar phases and eclipses. However, eclipses do not occur as often as full and new phases of the Moon. This difference is due to the fact that the orbital planes of the Moon and the Earth do not overlap. The purpose of this study is to describe and actualize a method to estimate the value of the inclination angle of the orbital plane of the Moon to the ecliptic plane. Essential steps of the estimation method and a geometrical construct are given to assist the visualization and calculation of the inclination angle. Measurements required for such an estimate are the arc lengths of the lunar and solar directions from the zenith direction of an observer. The estimation method was actualized at the full Moon date that occurred about three months after the full lunar eclipse in 2015. This study also provides students with the chance to realize the existence of orbital planes in the sky.