I'm trying to get some code working properly which will check for an eclipse.  I'm having some problems, and have narrowed it down to this: I thought the function CelestialBody.getPositionAtUT(double)  returns the position at the specified UT, but my tests are showing otherwise: Test code, which find the Mun and prints out the position at 5 days (ignoring the ScaledSpace.ScaleFactor for now): foreach (CelestialBody rock in FlightGlobals.Bodies) if (rock.name ==