A couple of random notes:
- You want to preheat the oven to a higher temperature, then turn it down as soon as you put the turkey in. Preheating: get the oven up to the target temperature, then leave it there for at least 10-15 minutes. The oven thermostat is measuring air temperature, but you want to wait for the oven walls to heat up. The reason to preheat to the higher temperature is to seal the meat more quickly, so it gets less dried-out by the longer cooking time.
- If you are using a convection oven, use a much shorter cooking time. I have a convection oven, but I don't use the convection when roasting turkeys. I'm never quite as satisfied with the results.
- For a 13# turkey, I think you'll be looking somewhere north of 3 hrs 15 minutes. Start checking earlier than that, both to hedge against me being wrong and against your oven running hot.
- Opening the oven door every so often isn't the worst thing in the world, but don't overdo it.
- 145 leg temp is too low. Double-check me on this, but I usually aim for closer to 180.
- Beyond the use of a quick-read meat thermometer, the eyeball test is the juices. Pull on a leg or wing and examine the juices that run out. If the juices are red/pink, it's not done. If clear, it's done.
- Unstuffed birds cook faster than stuffed birds.
- If you like gravy, you'll find that you get better gravy if you include onions.
- For reference stuff like this, I find that _The Joy of Cooking_ is still the best cookbook option. Older editions are actually better; the newer editions have updated the recipies to save labor, but they produce less optimal results. 1970s is a good era for JoC. Any editions published after Rombauer (Bombeck) passed away are suspect.
- The reason to cook upside-down is to make the breast juicier. It works quite well, and I recommend it, even though it sacrifices some of the best skin to the gravy.
- Lazy tip: besides doing all of the work with melted butter, you can take the dry or mostly-dry turkey, sprinkle on your dry seasonings, then spray it all over with a thin coat of canola oil. You can get spray cans of canola oil pretty much anywhere. For example, the regular "Pam" is plain canola oil. The oil helps seal the turkey and keep it more moist.