Okay, I researched it in the library and I still can't open this temple door. It's night time during a full moon- is there some other step I'm missing?
Viewing post in Caliross, The Shapeshifter's Legacy comments
No, if you have the ritual spell, and you cast it in front of the temple inside the forest near Tarkas during a full moon, you should get the door to open (you can tell there is a full moon because a symbol above the door appears). I just tested it and it worked, so I am not sure what could be the problem.
Equipment doesn't appear in your regular inventory, but it should appear in the "charms" sub-section. Anyway, if you did everything right you should be able to equip it in the "accessory" section of your equipment page. If you checked already, maybe send me a link to your savefile, and I can try to figure out what went wrong.