Possible Clues:

• Dark sky's omen
• Rule or controlling device pronounced the epitome of what's right
• See 12
• Come down and brake audibly
• Reason for a tarpaulin
• No Dr. ought to have this with the artist at home
• Not so fine for a ruler, by the sound of it
• Mac user's motivation
• Shine alternate
• "Still Falls the __": Edith Sitwell poem