1. I haven't got my NexDome yet (anticipation is killing me) but I'm looking at how things are dimensioned relative to each other. I saw a PDF schematic off the website that shows the dome centerline apparently where the center of the GEM OTA is pointing to vertical (the meridian) and dimension offset of the pier of like 12". Yet the Installation and User Manual essentially gives the impression that the pier and dome C/L can be identical (no offset for GEM mounts) and you have to have the Center of Rotation of RA and Dec axis dimensioned off the dome C/L.I have a friend who has ordered a NexDome and he insists the schematic diagram is correct.
2. Another question is I have a GEM mount and determining a north/south line is easy using a laser level since the mount is polar aligned and pointing true due North. How do you determine East/West?
If you use a tripod you can indeed move the mount to center the Ra/Dec on all axis.. the issue is more for people who put a permanent pier.. put it dead center in X/Y.
I do all my measurement in mm (I grew up in a metric system country). If you use TheSkyX, you can use any units.. as long as all numbers are in the same units (mm, cm, inch, feet, Angstrom, ..).