The plane of the moon's orbit is currently inclined at 5 degrees to the plane of the ecliptic. However, the plane of the ecliptic 'nods' relative to the invariable plane, according to wikipedia at least, with a period of about 100K years. It seems reasonable to believe that the plane of the moon's orbit makes a varying angle to the plane of the ecliptic. Does anyone out there know what the range of values of inclination of the moon's orbital plane to the ecliptic, and what the period of variation is? Is there ever an epoch when the planes are close enough aligned to give an eclipse every month? If so, what percent change would that give to annual total solar insolation?