How to take the pith off an orange?
Before you peel it, if you roll the orange around on a hard surface while pressing down firmly with your hand, it will help to loosen the pith from the orange segments. It also makes it much easier to peel if you take a sharp paring knife and score the skin of the orange in pie segments. That is all the way around from stem to bottom and stem again, then move the knife half way around from that initial cut and do this again. And then halve those four segments. Then loosen the peel at the stem end and lift each of the beginnings of those eight segments of peel with your knife. Then peel off with your fingers. Most of the pith will come off with these segments of peel.
