Ranger's Casting Proficiency Achievement

Can someone explain how the Ranger's Casting Proficiency Achievement is earned? (/ACH -> General -> Skill)
My Divination skill is 176, but in this achievement, the only box not checked is Divination. (same is true for the next few achievements). The checkbox reads "Reach the maximum skill in Divination at Level 50."

At first, i thought it meant a skill of 50, but in looking through the achievements I see that is not how this works. So what is the maximum Divination at level 50? and what about level 60?

your skills and their caps are listed in the Skills window. click the Skills button on your inventory screen

Understand... but what WAS the cap at 50 was the question.

250

285

So if you are higher than level 50 and your skill is 248/276 will you still get the achievement
when you finally reach 276/276
ty

Yes. The achievement is still given regardless of level. You can get the 50 at 110

You'll get the achievement when you reach 250 base in all casting skills. 250 is the maximum base skill possible at level 50.