How to maneuver around in LV when zoomed in?

I'm still new to Nikon D7000. I came from Pentax but still own my beloved K5. I need help usiing live view to manual focus on lets say a star/moon for instance. Infinity focus isnt perfect so this is what i'd do on my K5. So in LV I'd zoom in and move toward my subject using the arrow pad and manual focus til perfection. I read the manual and it says something about choosing normal or wide af to be able to move around when zoomed in. It dosent work even with af on. Sometimes I like to focus on distant objects for star trail shots. What can I do to fix this. It must be simple. Right???