Whenever I find a that takes a while to understand or has a poor title I'll edit it after I post my answer. I find myself doing this quite a lot so out of interest I started tracking the illuminator badge.
What I've noticed is that if I've edited and answered a post and then somebody re-edits the answer that my original edit will no longer count towards illuminator. It seems the only way to get the badge is if you have the last accepted edit on a question, as well as an answer.
Is this by design?