2022-04-28, 05:51 PM
It did not occur to me that it would come out that way. I guess what I should have said was the other satellites mentioned have crazy high eccentricities and some retrograde orbits (high inclinations). Iapetus is close to the norm in this regard. When I was using SPICE to correct the positions in the other software, Iapetus would creep out of position by 300 meters in under 14 hours of simulation. All software can be improved but some like ST works well and quickly when used in the appropriate manner. Being that Iapetus is 10th mag and at the end of April, does not have stars that might be confused with it for a good week, it may be a non issue plotting its position.