Best way to change my inclination?

[FinnBot5000]

I have a space station in a circular orbit around kerbin, and I am trying to get my inclination as close to 0 as possible. Right now it is at 1.2 degrees, which isnt much but as I am trying to dock other ships with this, I would like to get it closer to zero so that I can adjust my other ships orbits to get them to match up, and it would be easiest if I can just get them both around zero. I know that you point yourself normal and antinormal to change the inclination, but I dont know where in the orbit to do it (i suppose it wouldnt matter in a circular orbit???). Either way I am fairly new to this (yes Ik my space station will probably fail cause docking is hard) and any help would be great!

[James Kerman]

10 minutes ago, FinnBot5000 said:

I dont know where in the orbit to do it

To get a perfect 0° inclination you need to burn at either the ascending or descending nodes (An or Dn). It really helps to lower the thrust of your vessel when fine tuning.

[FinnBot5000]

11 minutes ago, James Kerman said:

To get a perfect 0° inclination you need to burn at either the ascending or descending nodes (An or Dn). It really helps to lower the thrust of your vessel when fine tuning.

Ok, thank you for the help! How do I make the nodes show up? I thought that you are supposed to click on the planet (and set as target?) but I cant set kerbin as a target.

[James Kerman]

2 minutes ago, FinnBot5000 said:

Ok, thank you for the help! How do I make the nodes show up? I thought that you are supposed to click on the planet (and set as target?) but I cant set kerbin as a target.

No problems, click on the vessel you are trying to RV or dock with and select it as the target. You should then see the An/Dn,

[FinnBot5000]

1 hour ago, James Kerman said:

No problems, click on the vessel you are trying to RV or dock with and select it as the target. You should then see the An/Dn,

Right now I am just putting the ship into orbit (not docking with anything). I want the nodes to show up for the planet.

[AlpacaMall]

Specifically for Kerbin: The Mun has 0 inclination, so you can set it as your target and match inclination with it. That’ll get you your AN and DN markers.

[James Kerman]

30 minutes ago, FinnBot5000 said:

Right now I am just putting the ship into orbit (not docking with anything). I want the nodes to show up for the planet.

Oh okay, sorry I misunderstood. I don't worry too much about achieving perfect planetary orbits, Eyeballing the orbit line of the Mun and your vessels orbit by moving your view around until they are both single lines should get you pretty close @AlpacaMall has a better suggestion.

You use the widget at the bottom left of screen to get planetary inclination.

[FinnBot5000]

6 minutes ago, James Kerman said:

You use the widget at the bottom left of screen to get planetary inclination.

That is what I have been using to get my inclination, but I am wondering how to go about changing the inclination to 0.
I (probably incorrectly) assumed that the nodes would be halfway between the periapsis and apoapsis, and I started with burning facing normal halfway between them, but that raised my inclination, so I burned antinormal and that lowered it by about 0.4 degrees but then it started climbing again.

[James Kerman]

9 minutes ago, FinnBot5000 said:

I (probably incorrectly) assumed that the nodes would be halfway between the periapsis and apoapsis

The An/Dn could be anywhere on an orbit. I think you could play around with a manoeuvre node to find it.

[FinnBot5000]

10 hours ago, James Kerman said:

The An/Dn could be anywhere on an orbit. I think you could play around with a manoeuvre node to find it.

Ok I will have to work on that later. Thank you for the help!

Edited October 1, 2021 by FinnBot5000

[king of nowhere]

you can visualize the inclination of your orbit by fiddling with the window in the bottom left of the screen. i don't remember the shape of the icon to select, but i do it all the time.

if you make a manuever node, you can also visualize the inclination after you'll have executed the manuever. you can play with this to see where to burn to achieve perfect 0 inclination.

yes, on kerbin targeting mun is easier, but the other method works for every planet

[FinnBot5000]

4 hours ago, king of nowhere said:

if you make a manuever node, you can also visualize the inclination after you'll have executed the manuever. you can play with this to see where to burn to achieve perfect 0 inclination

Ok, thank you for the help! I will have to look at that!

I eventually managed to get the inclination to 0 after just going around my orbit and manually trying to burn normal, if that didnt, than i tried antinormal, if that didnt work than I would move a bit further around the orbit and try again. If the incliation decreased at all then I would make a quicksave so if I messed up next time I could go back.

[AHHans]

20 hours ago, king of nowhere said:

if you make a manuever node, you can also visualize the inclination after you'll have executed the manuever. you can play with this to see where to burn to achieve perfect 0 inclination.

There's also an iterative process to improve a maneuver node:

• Without changing the position (on the orbit == time of the maneuver node) of the node, increase the radial dV of the node until it gives the minimum inclination. Because the widget shows only one digit after the decimal point there is typically a wide range where the inclination stays at the minimum value. Use the lowest dV to get to that value.
• Move the maneuver node around the orbit line (== change the time of the burn). When you move the maneuver node closer to the ascending/descending node then the resulting inclination will be lower, so move the node to where the resulting inclination is minimal. Again: because of the widget limitations there usually is a wide range where "nothing changes", but here try to get to the center of that range.

I usually only need two or three iterations of these steps to get to a maneuver that gives me "0.0 deg" inclination. (And then I usually mess up the burn, but that is a different story... )

P.S. When I do have the AN and DN displayed then I start my radial burn somewhat before the node and "push" the node to keep it in front of me while reducing thrust. That way I can get a very precisely matched orbit. (E.g. when a single puff from the RCS thrusters moves the AN and DN halfway across the orbit.