More moon node-talk

Event Date: April 17th
Time: 6:00 AM

Brief

   Yesterday, I showed the Moon, using it as a guide to find Neptune.  As a waning crescent, it is soon to fall into the glare of the Sun a couple days from now, and be too hard to see.  Besides, that, it will be reaching "new" phase, with its lit portion nearly completely turned away from us.  Looking at the image, the Moon is far enough south of the sub-horizon Sun: 12º to be approximate.  The Moon as a 13% waning crescent rises two hours before the Sun, at its given separation. 
In image one, is the Moon low towards the horizon, and its current phase.  Use the Moon to find much dimmer Mercury, which we used to find dimmer Uranus' location with optical aid yesterday.

Detailed

   On occasion at this time of year, at the same phase in about the same part of the sky, that the gap between Sun and Moon rise would be smaller: when the Moon is south of the ecliptic, and therefore, even further south of the Sun.  Because of the "precession of the nodes", the Moon is as much as 5 1/2º north and south of the ecliptic at two different parts of the sky.  Every 18.6 years, the Moon reaches these parts of the sky again at the same ecliptic latitude.  While in between, those extreme points move east to west in full circle; this translates to about 1.6º per month.  Since the Moon reaches the same part of the sky about every 27 days and 8 hours known as its sidereal period, it is either a little more north or a little more south, depending on where the nodes are--where its orbit meets with the ecliptic.  Since we see it north of the ecliptic in image two below, it is approaching descending node; where the ecliptic descends south of the ecliptic east of it. 

*click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

After the descending node finally reaches this part of the sky in late 2015-early 2016, the Moon's orbit continues to move south of the ecliptic at this point until 2021.  After that, each time that the Moon reaches this latitude, it will slowly become more and more north.Image two has Mercury unlabeled, while the orbit of the Moon, celestial equator and ecliptic are put in.