LIMIT DRAWN AS TERRAIN
A boundary of what can be seen is drawn with the same line as a boundary of what is there.
01 DEFINITION
Condition in which the reach of an instrument is worked out from conditions that keep changing and then drawn onto the same picture as the things it is looking for, so a limit of the observing is read with the confidence given to a feature of the world.
02 CONDITIONS
03 WHERE IT APPEARS
04 WHAT AEON WORKED THROUGH HERE
How far the instrument could reach depended on conditions that shifted through the day, and the reach was drawn on the same picture as everything else. An area shaded as beyond reach was read as an area where there was nothing, and the shading kept its shape on the screen long after the conditions that produced it had moved. The work went into what the picture says about its own edge — what produced it and when — rather than into drawing the edge more precisely.
What stays unresolved is how a drawn edge carries that it will move — an edge marked provisional is one people plan around anyway, and one drawn plainly becomes a place on the picture where nothing is expected to be.