Epsilon Eridani - Star System of Halo: Reach

[dprice1291]

Presenting my first creation using U.S., a replica of the Epsilon Eridani planetary system. I have taken efforts to ensure the accuracy of the real-world star system, its asteroid belts, its two known (real) planets (Epsilon Eridani b and c), whilst also ensuring the presence and accuracy of the fictional worlds of the Halo universe (Beta Gabriel, Reach, Circumstance, Tribute, and Tantalus).
Sources (for real system elements):
http://exoplanet.eu/star.php?st=eps+Eridani
http://en.wikipedia.org/wiki/Epsilon_Eridani

Sources (for fictional system elements):
http://haloresurrection.proboards.com/index.cgi?board=mapinfo&action=print&thread=12
http://halo.wikia.com/wiki/Epsilon_Eridani
http://halo.wikia.com/wiki/Reach

[dprice1291]

I had a little bit of trouble creating a stable positioning for the moons of Reach, Turul and Csodaszarvas. My impression from the game is that the smaller moon (which I take to be Csodaszarvas, based on the naming of the other moon after a prominent bird in Hungarian culture that I would suspect lent itself to the larger of the two) should be orbiting at the L1 point between Turul and Reach; during the game, I don't recall seeing the moons changing position relative to one another. I hope there is a way to create a Lagrange-snap function for bodies, as, even with my best placement, the smaller moon always ends up drifting from its position into an independent elliptical orbit around Reach.

Also, my original plan for the creation of the system was to mod the "Solar System and nearest stars" mod to make a representation of the Inner Colonies of the UNSC, including the Sol System, Epsilon Eridani, Sirius, and others. However, I ran into problems due to the ecliptical plane of E. Eridani being inclined relative to that of Sol, which seems to be the baseline of the entire mod. It was extremely difficult to find a way to tilt the planets to the correct plane, and I in fact found it to be too risky in terms of accuracy and potentially-wasted effort to try it at this stage. If someone knows of a way to fix this, please inform me.

I took a few liberties here based on vagueness or lack of data with the information I based this on... for example, the orbital velocities, masses, appearances, and locations of the planet's moons were up for interpretation, as no images exist of them and no information other than names is posted. Also, the two real-world planets, E Eridani b and c, are depicted here with no moons at all, which seems unlikely; here, I decided to forgo them, for the risk of taking too many liberties in design and breaching my intention of keeping this simulation simple and efficient for fans. With all features that are modified, I took efforts to ensure that they are modified 'within tolerances'; that is, if an asteroid belt is listed in scientific literature as having a semimajor axis of 3.00 ± 0.75 AU, I list it as between 2.56 AU and 3.23 AU, for realism (since distances wouldn't necessarily be so exact and round). I may make some designs in the future, but I find this model sufficient at this point, barring criticisms and fine touches.
I appreciate any feedback at all!  

[atomic7732]

About the plane, if you have any data on what the plane is (which I'm sure isn't hard to find), you just keep the inclination at the same value, and similar "node" values (within about 5 - 10 deg)

[dprice1291]

According to Wikipedia, "From the Earth, this [dust/asteroid] belt is viewed at an inclination of roughly 25° to the line of sight", speaking of the ecliptic of Epsilon Eridani (http://en.wikipedia.org/wiki/Epsilon_Eridani#Dust_disk). However, I'm not sure if this 'line of sight' means the Solar Ecliptic (although this isn't an unanswerable question).
I suppose a major problem is that I am a 'noob' to this program. For example, when I am looking at the rotation data for Epsilon Eridani, I notice it has 3 values, x, y, and z. I've been playing with them, and I notice that when I set them all to zero, the body has no inclination relative to the solar plane and is balanced like a top. I'm guessing the y-axis is the actual axis of rotation based on linear geometry. Does this mean I look at this number to derive the inclination of any planets orbiting it? And how do the other axes - x and z - factor in that? I'm probably just missing it, but it'd be really great to find out if my hypotheses are correct. I want to make a whole series of these systems as separate simulations because I am a straight-out Halo fan who wants to do his interest honor (as a gamer and lover of fiction), but preserve the scientific integrity and accuracy that I treasure (as an avid science enthusiast and paleontology student).
Do you know of any way to orient Universe Sandbox's provided plane (the one for placing objects in orbit around another) to a given object's equator, other than the Sun's (i.e. in simulations that include the sun as the central point, but include other stars which I want to add planets to, but have axial tilts)? That would immensely speed things up, for certain.

[Dan Dixon]

This is really great. Thanks for sharing this with everyone.