The visual helper "Target Equator" green line is a projection of the target planet's equator onto the Celestial sphere, as far as I know.
The first strange thing is that that line is purple in my installation (Orbiter 2016).
Beside that, I attached one image of Bennu and one of the Earth (for comparison).
I used the global frame (F2) and I oriented the camera to see the retrograde Bennu rotation. To see the line passing over the center of Bennu, I needed to look from about 45 deg nord.
Now I changed to a well known celestial body without changing the camera orientation. We see the south pole up (which is correct) and we see the line passing exactly over the equator when we look the Earth from over the equator, which is also correct, but that doesn't happen with Bennu (I hope that my "English" is clear enough).
I'm not totally sure that it's a problem, but it seems strange to me.
For a more accurate orientation of Bennu, you may want to figure out the axis LAN parameter in the .cfg file (currently set to LAN = 0 ).
The Wikipedia entry for Bennu gives RightAscension and Declination of the N.Pole, so it can be calculated from that. (I might have a go at some point).
Also, the rotation offset needs to be set (currently set to SidRotOffset = 0).
You might be able to do that if you have an image of Bennu with a time stamp from the spacecraft.
Since I use SPICE to do all the calculation, I can calculate and verify anything, but the problem is to understand the exact meaning of those parameters in Orbiter.
What I'm trying to do is to use Orbiter as a 3D visualization tool. All the bodies are moved with the SPICE library (I'm currently using Orbiter 2010) and I orient ORX using the NAIF's data file (which include also the instrument FOV). I'm currently intersted in the preliminary survey phase. In other words, I need a perfect setup!
Do let me know if you figure out those parameters!
You can bet!