Trijicon Accupoint for mid/long range hunting

[JimIsland]

What you are dimming is the fiber optic.

On the older scopes there's a collar. Newer ones have a dial. Both serve the same function which is to decrease or increase the amount of tritium.

 

[Macintosh]

The dial is fiber optic only. There is a wrap of fiber optic material (just like a bow sight) that absorbs ambient light from the large surface area on the side, and directs it through the core into a brighter glow in its center. The dial adjusts the amount of ambient light that the fiber optic is exposed to. This adjusts pretty quickly--it has nothing to do with days, its minutes. So in bright daylight, it can be "daylight bright" if you want it to be. This also means that if you are in a dark blind, you arent getting ambient light, so the fiber optic doesnt work the same way it would if you were outside. @Elkman17 "a few days in dark timber" has no effect ont he fiber optic--it's the preceding few minutes that matter. Remember, the darker the conditions, the less brightness is needed (and wanted) in the dot. If its dark, having the dot too bright is counter-productive. But in general my accupoint is an exceptionally good dark timber scope, for sure the best I've ever had a chance to use.
The tritium is in addition to the fiber optic, and is not adjustable, and is only for a faint glow when there isnt enough ambient light to power the fiber optic.