Observation Post
The Onslaught point of interest on the night versions of a map, which fires an illumination flare that both spots the enemies it lights and leaves them taking more damage.
Also known as illumination flare, flare point.
It replaces the Comms Center after dark, and the reason is the night itself. On a night map everyone sees less far and hides better, so vision that used to be handed to a team wholesale is now aimed: instead of spotting the enemy team wherever it is, the flare illuminates one area of the map that your team chooses.
What it does there is two things at once. Every enemy inside the lit area is spotted, and while they are lit they take 10% more damage. The area stays lit for 25 seconds and shrinks as it burns down, so a flare is a window rather than a state: it is worth firing over ground your team is already shooting at, not over ground it hopes to reach later.
It is not a secret weapon either. Both teams see the flare in the sky, its position and size on the minimap, and which side it belongs to, so the side being lit knows it is lit and can leave. That is what makes it a timing tool: the flare is only worth its cooldown if the damage lands inside the window it opens.