How does Coleridge create a supernatural and mysterious atmosphere in the opening section of Christabel?

Christabel opens on a mysterious note. It is a chilly night, not dark, but the moon seems dull. The time is midnight and the castle clock strikes twelve. The hooting of the owl and drowsy crowing of the combine to add mystery. Finally there is the popular superstitious belief that the spirit of Sir Leoline's dead wife stalks this hour and the mastiff bitch growls at her appearance. With all these Coleridge creates the mysterious and supernatural atmosphere in the very opening section of the poem.