Chrono Vision is the power that a Palimpsest has. It is the power to read the events occurred through time, always seeing them and being able to show something in particular to others.
These Casters see different points in the past, present and future all at once, so their minds are always a little blurred. Because this ability is constantly active they have some trouble to identify what is really in front of them and what happened into the place during the past.
Even if this power can't be turned off, it's possible to focus on a specific moment or thing and find what was lost or see whatever the user or another could search. To show the visions, and maybe find the specific layer of time, the user need to form a circle, all the present then will see what the Caster sees.
Even if it was stated that Palimpsests can see the future it's not explicitly shown. It could be a misconcept or, maybe, the Casters themselves can't distinguish one from the other with this ability, or something similar.