Scope question

[Raging480]

I just bought a NEF .243, used, and it came with a Tasco Lumina, 3-12x luminated recticle scope.  First, I know Tasco went out of business, second, I know many of you sophisticated hunters won't have anything to do with a Tasco.  BUT, I didn't see a battery or switch on this, and I don't have the papers for it, is anyone familiar with this product?  Second, I am fairly new to the world of scoping a gun, what is the dial on the front of the scope for?  I don't see those on lower powered scopes like the ones on my slug gun and muzzleloader.  Thank you for any helpful replies.

[Zachary]

I what is the dial on the front of the scope for?  Thank you for any helpful replies.

I can't say with 100% certainty, but much more than likely, it is an AO (Ajustable Objective), meaning that you can adjust the objective at a certain distance.

Let's say, for example, that you are looking at a deer at 150 yards.  Well, then you would adjust the AO to 150 yards.  If the animal is 375 yards, then adjust it accordingly.  In this manner, you get a very sharp image.  If the animal is 375 yards away, but the AO is adjusted to only 150, or even 200, then the image will not be sharp.

Usually only scopes with magnifications of 12x or higher have AOs.  I have never seen them on scopes under 12x.

Zachary