The National Turkey Federation recommends roasting a turkey in a 325 degrees F. oven until a meat thermometer indicates the internal temperature registers 180 degrees F. in the thigh and 165 degrees F to 170 degrees F in the breast. Pop-up timers are helpful as a preliminary step in judging the correct temperature, but a meat thermometer is the best final authority to determine doneness. Click here for more information:
http://www.eatturkey.com/consumer/cookinfo/turroast.html