Optically Centering your scope - Very useful

Telescopes and Optics used in HFT

Optically Centering your scope - Very useful

Postby AGF » Thu Oct 25, 2012 12:23 pm

This is an extract from Saxons post , I just had to post it . The info is of great value to anyone shooting a scope. Thanks Saxon

Centring your scope
Before you fit your scope, you should set the turrets so that your scope’s internal workings (the erector tube) is in the centre position. There are a couple of ways to do this.

Centring the turrets
Turn the elevation turret to the limit of it’s travel (don’t put too much pressure on the final clicks in case you permanently damage your scope).
Slowly turn the turret (counting the clicks as you do so) until you reach the opposite extent of the turrets travel.
Divide the number of clicks you’ve just counted by 2 and turn the turret back that number of turns.
Repeat this for the windage turret.
You should now have each turret set in the centre of it’s range of travel.
This will give you a reasonable rough approximation of the optical centre of your scope and a good starting point for any further centring you want to carry out.
Optical centring with a mirror
If your scope has a variable magnification, select the lowest magnification. Start with your parallax set as above.
Find a mirror that can be laid flat on a flat surface – the thicker the glass on the mirror the easier it makes things.
Stand your scope up on the mirror so that the objective end is rested on the surface of the mirror.
Look through your scope from directly above, if it’s too dark you may need to shine more light onto the surface of the mirror (this is where having thick glass on your mirror will help because the thicker the glass the more light it’ll let through)
You should be able to see two sets of reticles when looking down your scope. If you can’t, then this method won’t work for you. Try to get more light reflecting back up from the mirror and try resetting the parallax to infinity if you have an adjustable parallax scope. If nothing works use the harder method detailed below.
Adjust both turrets until the two reticles that you can see are perfectly aligned with each other.
That’s it – you now have one optically centred scope.
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