Combine apples and lemon juice in a large mixing bowl. Combine sugar, flour, lemon rind, nutmeg, cinnamon, and salt. Spoon over apple mixture; toss lightly to coat well.
Spoon filling evenly into a greased 9-inch pie plate, and dot with butter.
Roll pastry to 1/8-inch thickness on a lightly-floured surface; place over apple mixture. Trim edges; seal and flute. Cut slits in top crust to allow steam to escape. Bake at 350° for 1 hour. Cool 10 minutes before serving.