Originally Posted by royinidaho
Watch it over a period of time and you may see that one conditions occurs more than others. This is the condition that you want to shoot under.
My survey theodolite has a 30x scope, and mirage is a problem for me, too.
I try to take long shots at low-mirage times, but when I can't avoid it, the above is good advice. Mirage is usually variable.
We call our technique "meaning it out", or picking the repeatable sight point. Watch the crosshairs come back to a point when the dancing is lower, and then average that out.