The extent of one's perception, understanding, knowledge, or vision
on the horizon
The sun peeked over the desert horizon to the east.
The sun lingered on the horizon, as if waiting for the closing clouds.
Cassie glanced at Bordeaux, who was watching the horizon apprehensively.
But with all his good qualities Frederick was not the man to take a clear view of the political horizon, or even to recognize his own and his country's limitations.
In this case the second bow is much fainter, and has its centre as much above the horizon as that of the direct system is below it.