pro & retrograde command reference

[micho]

Hi!

I'm flying DG Mk4, btw I like yours too, Dan, but is too complex and I'm trying to get to
the Moon. I'm now some 45,000 km from its surface and now and then I do correction burns
(hopefully the right way) and therefore I need also prograde and retrograde commands.

The question is to which orbit/planet do these commands refer while they're making attitude
changes of the spacecraft. I have a reason to believe that they refer to the Sun, I just want to
double check with you guys and girl . I'm almost sure about that because when I change HUD
orbit reference from Earth to Moon and Sun, Sun's appears to be the straight one - vertically
across screen.

Is there any way to change that reference, because after all I'm travelling to the Moon and not
towards the Sun. And also when I look at it from the outside the first impression I get DG might be
a little under the Moon but exactly leveled with the Sun. So you see, I'm assuming that due to
commands refering to the Sun's orbit my Moon's orbit insertion might fall distorted.

According to the Moon's surface my longitude is decreasing and latitude is increasing. Is this
normal?

[C3PO]

I'm not sure but I think the pro/retrograde modes of the autopilot always point to the body that
has the largest influence.

Has anyone else tried?

[Alan Lile]

I am farely sure that what c3po said is true...pro/retrograde is determined by the body of greatest
influence....I have been in one or the other mode traveling from one body....and when another
bodies gravitational pull takes othe....the pro/retrograde changes.

[CarlosTheTackle]

The current body that is referred to shows up on the Orbit HUD (in the top left corner of the screen
I think).

And yes, it is the most gravitationally significant body, so until you get reasonably close to the
moon, it will be the sun.

Makes doing a retrograde burn relative to lunar orbit a bit tricky, huh? What I do, if I want to do a
slow-down burn approaching the moon, but before I have it as my main gravity source, is to use
the surface HUD, which can be set to whatever body you want, with Shift-R (need the Surface MFD
up too). Then you can use the auto-pilot level function (L) to lie flat relative to the moon, and
perform prograde and retrograde burns using your velocity vector pipper to point yourself (yaw) in
the right direction.

[CarlosTheTackle]

Actually, that last note is BS. Sorry, it only really works in near-circular obrits, certainly not when you're on the long
bit of a narrow ellipse.