Brown onion in oil.
Add tomatoes, stirring until mixture reaches boiling.
Lower heat and simmer, covered, 5 minutes.
Add wine, parsley, celery, and salt and pepper to taste.
Simmer 30 minutes.
While tomato sauce is simmering, parboil shrimp 2 minutes in 3 quarts boiling water with 2 teaspoons salt.
Add shrimp to sauce.
Simmer 1 minute.
Garnish with feta.