Roll half of pastry to 1/8-inch thickness on a lightly floured surface; fit into a 9-inch pie plate. Set aside.
Combine sugar, flour, nutmeg, orange juice, syrup, and butter in a large mixing bowl; stir well. Add apples, stirring lightly to coat; spoon filling into pastry shell.
Roll remaining pastry to 1/8- inch thickness; place over filling. Trim edges; seal and flute. Cut slits in top crust to allow steam to escape. Bake at 375° for 15 minutes. Reduce heat to 300°, and bake an additional 45 minutes. Cool pie before slicing.