Some years back I read about a way to center a reticle that seems much easier and more accurate than turning the dial lock to lock, counting clicks and going halfway back.

I go into a well lit bathroom turn and put the objective squarely on the surface of the mirror (turn to high power if adjustable and remove any caps or covers).

While holding it on the mirror look through the ocular end and if the reticle is not perfectly centered you will see two reticles (you may have to adjust your view to have them both appear). You simply turn the elevation & windage adjustments until the reticles are aligned and it's centered.

I'm not an optical engineer so can you give me a simple explanation how this works?


thanks,

Rob

Not an optical engineer myself, but I would say it's because when the scope is not in it's optical center, the erector tube is at an angle. When this is true, and you hold the scope up to the mirror, you are looking through the scope at a slight angle at the mirror. Thus you see the actual reticle and the reflection of the reticle separately. When the erector tube is adjusted to be straight (scope is optically centered), you are looking the the scope at the mirror straight on, and thus you don't see the reticle's reflection as it is directly behind the reticle.

thanks TXRam,

Rob

TXRam,

That sounds good. I had no idea why it works, I believed it and used it.

Have used this method for years. It is quick and works quite well.

The really good thing about this method, is that it finds the optical centre of the lens system, which is not always the case when a scope is mechanically centred.

Ted

Absolutely. I just optically centered a new Weaver, the elevation dot lined up with zero but the windage was out by 10 clicks.