Problem: I like to make even grids, especially for exploring or making hiways. Currently, that means a lot of counting.
Operation: If the active BH is carrying one, co-ordinates show at the top of the screen. You don’t have to place it. Co-ordinates are based on the original portal, not the poles, to maintain the initial mystery.
Cost: Metalwork Bench, level 2. Maybe also need to travel 1000 blocks from the origin before you can make it. (More realistic, but probably harder to program.)
Real World History: Wikipedia says the sextant was invented in 1731, but also says there are records of its use around 1600. Maybe the later date is a better design? The steam engine was patented in 1698.