Inclination - how to zero without a reference?

[Spricigo]

8 minutes ago, Zhetaan said:

reference

One can use whatever reference exist or use a myriad of methods to create one. Still, that is not the question. 

That said, I also fail to notice how launching from the north pole would ensure a perfect 90degree inclination. Piloting errors can screw a polar orbit as easily as it can do to a equatorial one. Let alone coriollis effect. 

 

[Zhetaan]

The Coriolis force is only relevant when moving between points of varying displacement from the axis of a rotating frame of reference.  The pole has rotation but the radial displacement is zero; to launch from the equator (high displacement) towards the pole (zero displacement) causes a great deal of drift.  To launch from the pole (zero displacement) to the other pole (also zero displacement) gives no drift and no Coriolis force; in effect, by orbiting above the poles you leave the rotating frame of reference entirely and let the planet rotate under you--which of course is why polar orbits are so nice for surveys, but I digress.

Consider:  you launch from KSC and head due north.  As the planet's surface curves towards the north pole, the radial distance from Kerbin's rotational axis decreases, so the surface velocity also decreases; you retain your equatorial eastward surface velocity, so as you move farther north, you also drift east.  The end result is that if you set your heading to 0° on launch and never change it, you will end up in an inclined but not 90° polar orbit.  In order to get 90°, you need to launch somewhat northwest in order to cancel that eastward surface velocity.  Now consider:  you launch from the north pole and head due south towards KSC.  You have zero eastward surface velocity, but of course Kerbin's equator does not, so as you head south, KSC pulls to the east of you and you end up passing it somewhat to the west.  As you continue heading south, however, that eastward surface velocity drops back to zero, and assuming that you held an exact 180° heading the entire time, you will pass directly over the south pole with no correction required.

Naturally, you have a point about pilot error, hence the need for a stable rocket and heading.  The reason to use the pole is because the pole makes achieving 90° inclination easier--that's not the same as saying it becomes easy.  Actually, I imagine the task to be quite difficult.  Additionally, since the navball does give a heading readout, deviation from that heading gives a means to detect, albeit not necessarily prevent, pilot error, provided that the character of the launch is such that no deviation is expected.  This happens only in two conditions:  launching from the equator to an equatorial orbit, and launching from the pole into a polar orbit.  Everything else has to deal with the heading changes normally associated with great-circle navigation.  There is no way to detect the equator in KSP, but the compass (which is admittedly some kind of alien spacemagic compass that always points to true north and doesn't depend on magnetic fields) does give a way to detect the poles.

Finally, since you have repeated yourself twice and I have no desire to cause you the frustration of doing so a third time, you have my apologies for failing to answer your objection that I am not answering the question asked.  The answer is that the fact that inclination is defined as an angle between the orbital plane and a reference plane means that if truly no reference exists, then neither does inclination:  it is a null question of the same order as, 'How much is three added to?' However, given the context wherein the original poster mentioned that being able to use the Mun was 'cool' for Kerbin but wanted a general reference, I took the question as meaning, 'How to zero without a readout or an equatorially-aligned reference point?' in which case it is possible--albeit difficult--to construct one from the available tools because the poles can be found and do provide physical reference points from which the equatorial references can be derived.

[Spricigo]

2 hours ago, Zhetaan said:

There is no way to detect the equator in KSP,

 

https://wiki.kerbalspaceprogram.com/wiki/KerbNet

 

 

[Zhetaan]

15 hours ago, Spricigo said:

[Cool picture]

Nice!  In that case, all you need to do is open that window and watch.  The extremes of latitude variation give the inclination.  It would probably be better to find those extremes for one spacecraft and then use that as an initial reference by which one zeroes the inclination of a second spacecraft, with checking using the scanner to ensure that one never deviates from the equatorial orbit.

That made all of this rather a lot easier; thank you very much.

[Sacs]

Something I usually do is to grab one of the early 'Rescue from Kerbin orbit' contracts,  the first ones are almost always in a perfect equatorial low orbit.  When I get to the target, I rename it to 'Inclination Zero' then leave it there as my reference.  :-)