Scott,
With everything so far described and the attached images I would personally hack the 4 sides and cut that conduit. Question. Why was the outlet placed out that far from the pier? Cut that out and cut over to the pier removing the four sides. Another question. In your one image after the concrete pour showing the pier, what are those pads on the outside of the pier? That looks like the thick felt or whatever it is between my sidewalk pads.
Of course when you go to cut this concrete remove "everything" from the observatory. Cover what you can. You have a load of room to work in there. A decent exhaust fan working towards you door opening will help keep the particulates down. Go slow, be patient and you will have an isolated pier.
Another test of your pier issue is to have someone jump anywhere in the observatory while you are viewing. Of course the webcam idea is the best. Or a live image view of say the moon while walking around.