Orient is from the present participle oriens 'rising' from the deponent verb orior, the past particple of which is ortus. So, the verb should be ort and the noun should be ortion. But that never happened, so we have to settle for the strange word orientate and its noun orientation. If you don't accept one, you shouldn't accept the other. Sure, it violates the grammar of Latin, but then so does the word bus from omnibus.