I'm playing Career mode on normal difficulty, and I took on one of those "put a probe in this specific orbit" contracts. I did it, but I'm still having trouble visualizing a few things.
For the sake of argument, consider a rocket/probe orbiting Kerbin with a 5 deg inclination. Let's say the apoapsis is 80k and the periapsis is 75k. Now then, I can visualize my orbital plane with respect to Kerbin just fine. What I mean is, if you could place a stationary camera at, say, the ascending node,

There's a celestial coordinate system used to measure the orbital elements. Zero longitude points in the direction of a point in space that is fixed relative to the stars. In real life, zero longitude is along the line formed by the intersection of Earth's equatorial plane and the ecliptic plane, pointing in the direction of the vernal equinox. In KSP it is not entirely clear what defines the direction of zero longitude.
One thing I've noticed, and this is totally unofficial, is that whe