Its location is semi-random each run, but does follow a set of rules and has a certain consistency about it. It shouldn't be as hard to find as you have experienced...
Have you been lighting up active sensor bursts every once in a while as you scout out the nebula on the outskirts of the system? There are some *things* that will help lead you to the objective.
yeah, i have, i've been either sticking outside of the ring or actually in the nebula while spamming active sensor bursts every 30 seconds or so
i even hacked into Tiangdong's sensor array to try and get a bit of edge