Nodes .... and other stuff you probably didn't node before (sorry).   Please use your own word when answering all questions.

Part 1 - What is the astronomical meaning of a node?

You learned in geometry that the intersection of two planes is a line.  If you place a circle on each plane, the circles intersect at two points.  These points of intersection are called nodes.

Part 2 - Nodes are sometimes referred to as ascending or descending.  What does this refer to?

ascending node            descending  node

You have already seen many intersecting circles in this class.  Usually there is something moving along one of them.  When the object gets to a node, it will either be going up (which defines the ascending node) or down (which defines the descending node).

Part 3 - When referring to the celestial equator and the ecliptic, where are the nodes?  Please give a name (used in unit 1) for both nodes (you don't have to distinguish between the two types).

Part 4 - Nodes are quite often referred to when discussing eclipses (solar or lunar), or transits (of a planet crossing in front of the sun).  Your job is to make this connection clear.

For an eclipse to occur, things must line up.  The plane that the moon orbits the earth is tilted 5 degrees with respect to the ecliptic (the path of the sun).  It should be clear that things will only line up at the nodes.  Several astronomy books simply say you can expect an eclipse (solar or lunar) when both the sun and the moon are at the nodes, but that doesn't mean much unless you understand that things are on the same plane when they are at a node.  In other words, when the full or new moon is at a node, the sun, earth, and moon on the same line.

Part 5 -  Why don't they ever pinpoint and label the lunar nodes on a sky map?  Explain.

Sky maps never plot the orbit of the moon (let alone the nodes) because they change with time.  The orbital plane of the moon "wobbles" in a cycle that takes just over 18 years to complete.  Look at the image above and you see the nodes appear at the top and bottom of the image.  If you wait about 9 years, they will appear to the left and right as the red circle shifts its position in space.