Remove the turkey neck from the cavity and the giblet bag from the neck. Rinse the bird with cold water, inside and out, and dry very well.
Rub olive oil all over the bird. Season the bottom side of the turkey with all seasonings.
Place the turkey breast side up on a roasting tray in a roasting pan. Season the inside of the cavity with all seasonings and place half the onion, 8 cloves of garlic, fresh thyme, fresh sage, celery, and orange halves in the cavity.
Place the other half of the onion and 2 cloves of garlic in the neck area. Season the top of the turkey with all of the seasonings.
Place the meat thermometer in the thickest part of the thigh and place it in the oven.
Roast for about 3 hours or until the meat thermometer reads 180 degrees, basting every 30-40 minutes. Let the turkey rest for 20 minutes before carving. Enjoy.