One is far away, the other is very far away.
They are not in the same spot, just lined up in the same direction from the location you were in at that time.
For example:
X = you.
----- = the direction.
1 = lighthouse 1.
2 = lighthouse 2.
X-------------1-----------2
It's kinda hard to represent direction 8 exactly so I used "----"'s to represent direction 0, which is close to 8 and which isn't too big a hassle using regular writing style (left to right).
Both locations with lighthouses are within a certain range, that allows you to see the light of the lighthouses.
If you'd come closer, you'd possibly see the name of the closest lighthouse, and a general direction of 8 for the 2nd lighthouse that you saw in that direction, unless they were real close to eachother (as close as a few hours by foot, I reckon, would let you see both lighthouses' names, but I could be wrong).
There is an old thread somewhere which better explains at what range you see a lighthouse and at what range you see it's name, I'm not going to look for that right now but I do remember it was measured in pixels.
Edit:
Gah, while I was typing out this long reply, UloDeTero beat me to it with a shorter one...
