Position the observer between two objects

[TimeHorse]

I'm sorry if this has been asked before because I can't think of good keywords to search this concept but I'm at a lost for how to do this.

What I want to do is position the observer between two celestial bodies A and B such that it is looking at B with A directly behind it and if there was a line in 3-space between A and B the observer would lie upon it. Next, I want to define my height above B to a fixed distance FROM THE CORE OF THE OBJECT (not its surface). Then, I want to synchronize my position with respect to these constants: remain on that AB line at the distance from B as specified earlier.

Is there a way to do this? The software manual says that "Goto Object" is relative to the object surface, be it in km, AU or the relative unit of Radii. If this is true, then if I subtract the radius of the body from the desired distance from the body I should get the desired distance, but I've noticed that sometimes I type in a small distance and it calculates me as being at a negative height the next time I click "Goto Object". So I am confused by this.

But more confusing is how I set up my position so that it is locked BETWEEN two object rather than in a way where both objects can be visible.

As an example, say I want to always view the Earth centered such that the center of the display is the point on the Earth where the Sun lies directly over it, at a fixed height. But I want to do this arbitrarily, such as the Earth-Moon system or the Mars-Ceres or Sun-Ganymede. Is this even possible?

Jeffrey.

[selden]

I think you'll have to write a CelX script to do it. Determine the positions in xyz coordinates of the specified objects and place the viewpoint along the line between them, looking at the appropriate object. The algebra to do the position calculation is relatively straight forward.