Lunar Terminator Shadow Orientation
Posted: 28.03.2008, 20:40
I'm trying to get a reference frame to show the Lunar Libration. I'm 99% of the way there with this:
When I go to this location, then center and track the moon, I can see both the effect of libration and the changing distance. But....
I am trying to orient myself so the lunar terminator is always "vertical" in my field of view; i.e., the northern-most and southern-most points for a vertical line. I thought that's what I had with the above bodyframe. But it's obvious when watching that the line it sweeps out is often not vertical and this can be seen at some quarter-phases most clearly.
How can I define this frame?
roland
Code: Select all
"LEO Moon Track" "Sol/Earth" {
Class "Invisible"
Radius 0.001
OrbitFrame {
TwoVector {
Center "Sol/Earth"
Primary {
Axis "x"
RelativePosition { Target "Sol/Earth/Moon" }
}
Secondary {
Axis "y"
RelativeVelocity { Target "Sol/Earth/Moon" }
}
}
}
BodyFrame {
TwoVector {
Center "Sol/Earth"
Primary {
Axis "x"
RelativePosition { Target "Sol" }
}
Secondary {
Axis "y"
RelativeVelocity { Target "Sol/Earth" }
}
}
}
FixedPosition [ 7000.0 0. 0]
RelativeVelocity { Target "Sol/Earth/Moon" }
}When I go to this location, then center and track the moon, I can see both the effect of libration and the changing distance. But....
I am trying to orient myself so the lunar terminator is always "vertical" in my field of view; i.e., the northern-most and southern-most points for a vertical line. I thought that's what I had with the above bodyframe. But it's obvious when watching that the line it sweeps out is often not vertical and this can be seen at some quarter-phases most clearly.
How can I define this frame?
roland