Inclination - how to zero without a reference?

[Behemoth1702]

Hello guys,

just wondering. If orbiting around Kerbin with an inclination of 0.5, how to zero this out? I know that if you have a target you see AN and DN, but with kerbin orbit you don't because you can not target kerbin...

So I wonder - how to do this? If the mun is zeroed, can be used and that's cool. But for a general guide?

Thanks in advance!

Edited December 30, 2014 by Behemoth1702

[tomf]

The Mun is in a 0 inclination orbit so you can target it to get a reference. Otherwise I don't think it will be possible without mods. In my game I Kerbal engineer that will tell me my current inclination, and the fine maneuvre adjustment mod auto create nodes at AN or DN.

You might be able to monitor you latitude in the spacecraft information and when it switches from +ve to negative or the other way round that is one of the nodes.

Edited December 30, 2014 by tomf

[Behemoth1702]

The Mun is in a 0 inclination orbit so you can target it to get a reference.

Thanks. But what if a planet has no moon/reference point and all I have is theinclination readout from a mod?

[Jimbimbibble]

Just burn normal/anti-normal when you get to the node.

[Sirrobert]

No, unfortunatly there is no inclination readout in stock. And thus no way to get a specific inclination without already having a reference in orbit

[klesh]

You've got two eyeballs, only one is needed to guesstimate.

[Srpadget]

You either need a mod, or some existing object in a zero-inclination orbit to act as reference. (Kerbin has Mun, as noted above.)

In career, I treasure "Launch a satellite into an equatorial orbit around ..." contracts for exactly that reason--they give me a zero-inclination reference. And I *keep* those satellites to use as navigation aids (most contract launches I delete soon after completion because they clutter up map view so badly).

If I may ask, why do you need a precise zero-inclination orbit reference? Given the imprecision of a typical KSP trajectory, and the relative ease (low dV) of small plane changes in the game, when is 0.5 degree inclination "not good enough"?

EDIT: Re-reading the discussion, I see you DO apparently have a mod that provides inclination...but not the line of nodes (or at least not in a usable format)? If you have access to your craft's lat/lon, you could do your normal/anti-normal burn just as the latitude crosses zero (going from negative/south to positive/north would be the ascending node, and vice-versa).

Edited December 30, 2014 by Srpadget
re-read OP, answering the actual question

[Behemoth1702]

Thanks for all the replies guys!

You either need a mod, or some existing object in a zero-inclination orbit to act as reference. (Kerbin has Mun, as noted above.)

In career, I treasure "Launch a satellite into an equatorial orbit around ..." contracts for exactly that reason--they give me a zero-inclination reference. And I *keep* those satellites to use as navigation aids (most contract launches I delete soon after completion because they clutter up map view so badly).

If I may ask, why do you need a precise zero-inclination orbit reference? Given the imprecision of a typical KSP trajectory, and the relative ease (low dV) of small plane changes in the game, when is 0.5 degree inclination "not good enough"?

I could have written any value. I'm just wondering whether there was a way, that's it.

@ Satellites in 0 inclinaction - doing the same, haha.

[LethalDose]

EDIT: Re-reading the discussion, I see you DO apparently have a mod that provides inclination...but not the line of nodes (or at least not in a usable format)? If you have access to your craft's lat/lon, you could do your normal/anti-normal burn just as the latitude crosses zero (going from negative/south to positive/north would be the ascending node, and vice-versa).

Exactly this. You can never reduce your inclination below your current latitude, e.g. if you're at 10 deg latitude, it's impossible to burn at that point to get an orbit with inclination below 10 degrees. The good news is that, without exception, every closed orbit will cross the equator (Lat = 0) twice in a period. So just wait till you're crossing the equator to make the burn.

I know KER and VOID provide this data, I'd be shocked if MJ didn't as well.

[Anquietas314]

I know KER and VOID provide this data, I'd be shocked if MJ didn't as well.

I'll just add that KER and iirc MJ provide a readout of time to (equatorial) AN/DN as well. I've never used VOID but I suppose it might too. Looks like it doesn't

Edited December 30, 2014 by armagheddonsgw

[Behemoth1702]

Thanks for all the replies guys! With MechJeb or Kerbal Engeneer Redux I'll be able to zero my inclination, hehe.

This is marked as "answered".

[Ethen Sun]

You could go into the save file, if you really need to know.

Go to persistence.sfs, use Ctrl+F to find your craft, and it will be there in its orbital characteristics.

[Kryxal]

Here's a thought ... you could probably at least get your inclination below 1 degree by aligning normal or anti-normal and paying attention to your heading.

[Greenfire32]

On 8/28/2017 at 10:41 AM, Ethen Sun said:

You could go into the save file, if you really need to know.

Go to persistence.sfs, use Ctrl+F to find your craft, and it will be there in its orbital characteristics.

 

1 hour ago, Kryxal said:

Here's a thought ... you could probably at least get your inclination below 1 degree by aligning normal or anti-normal and paying attention to your heading.

The last post in this thread was made almost 3 years ago...

[Vanamonde]

10 hours ago, Greenfire32 said:

 

The last post in this thread was made almost 3 years ago...

But the question is still relevant. 

[Greenfire32]

55 minutes ago, Vanamonde said:

But the question is still relevant. 

 

On 12/30/2014 at 0:29 PM, Behemoth1702 said:

Thanks for all the replies guys! With MechJeb or Kerbal Engeneer Redux I'll be able to zero my inclination, hehe.

This is marked as "answered".

Just saying, OP got what they wanted and has since moved on. That's all that my point was.

[Superfluous J]

And now that certain aspects of Hyperedit are in Stock, there's another way to do this, on any planet.

1. Make a small ship. It can just be the cheapest thing you can build, but I'd pick maybe a Stayputnik so it doesn't get marked as debris.
2. "Launch" it, and on the launchpad open the Alt-F12 menu.
3. Go into the Orbits section, pick your planet of choice (Doesn't have to just be Kerbin) and set the orbit.
4. You now have a craft orbiting exactly equatorially, that you can target when needed. You paid for it and it's otherwise useless, so you shouldn't even feel bad about "cheating."

[evileye.x]

Honestly speaking, it does not make sense - to play KSP without orbital information display... (and dV information as well...)

So, pick up KER or 

 

[Hotaru]

32 minutes ago, evileye.x said:

Honestly speaking, it does not make sense - to play KSP without orbital information display... (and dV information as well...)

Don't forget that some people either prefer to play stock (for a variety of reasons, such as the extra challenge or the consistency of experience with other players) or can't use mods (most notably consoles)--and therefore it would still be nice to figure out a way of doing this in an unmodded game.

Unfortunately I don't think there is a way to get perfect zero inclination around an arbitrary body without mods on any platform (since consoles unfortunately don't have access to the debug menu). Any 3 of those 4 conditions are easy to achieve, but I can't think of a way to get all 4: eyeballing it gets you everything except a perfect inclination, using the Mun doesn't work anywhere but Kerbin, using mods requires using mods (funnily enough), and the debug menu isn't available on console.

I guess which option is the best depends on which kind of purist you are.

Edited August 30, 2017 by Hotaru

[Palaceviking]

On 30/12/2014 at 4:34 PM, Sirrobert said:

No, unfortunatly there is no inclination readout in stock. And thus no way to get a specific inclination without already having a reference in orbit

Mün is at 0 inclination,  target that

[Spricigo]

6 hours ago, Palaceviking said:

Mün is at 0 inclination

The (years old) question is not "what can be used as reference?"

 

 

[Palaceviking]

2 hours ago, Spricigo said:

The (years old) question is not "what can be used as reference?"

 

 

Granted...KER should be stock 

[Zhetaan]

I have a possible solution--possible because I have not tried it myself to verify it--that would take quite a lot of work, but may be able to supply you with a counter-reference.  It requires you to take a rocket to a pole, set it up there, and launch it into a pure polar 90° orbit.  Finding the pole can be done with precision (follow the compass north or south until it won't let you go north or south any more; also, there are usually easily-identified terrain discontinuities at the poles ... so perhaps you should avoid any cliffs), and the rotation of the planet there alters your delta-V (and therefore heading) by exactly zero.  Eliminating the vector addition on account of planetary rotation makes a polar launch one where aiming along a heading of due north or south will result in an inclination of exactly 90° (or -90°); the only other way this can happen is in a launch due east or west from a point on the equator.  Achieve polar orbit by holding the heading; any subsequent launches can get the inclination by taking the relative inclination to the polar rocket and subtracting 90°--or the next launch can use it to achieve zero inclination and then you can use that as a reference.

[Spricigo]

4 hours ago, Zhetaan said:

you can use that as a reference.

Again, the question is what to do when there is no reference. 

BTW I'd ask why the OP want a perfect equatorial orbit if he don't need to match inclination with anything.  But I forget where I let deLorean's keys.

[Zhetaan]

1 hour ago, Spricigo said:

Again, the question is what to do when there is no reference. 

BTW I'd ask why the OP want a perfect equatorial orbit if he don't need to match inclination with anything.  But I forget where I let deLorean's keys.

As I wrote, use a satellite in a polar orbit as a reference.  Getting to that is, so far as I know, possible but tedious:  you can use the compass to find the North Pole (find the place where every direction is 180° and you're there), which gives an exact 90° latitude reference.  Launch a rocket from there at a 180° heading and so long as it is stable in flight and held at that heading, the resultant orbit will be exactly 90° inclination because launching from the pole eliminates effects of planetary rotation.  Use a subsequent satellite to target the polar satellite and subtract 90° from the relative inclination to get orbital inclination.  If you can get relative inclination while targeting a landed object, then it becomes easier; plant a flag at the pole and you don't need the polar satellite.