Corn Chowder with onion

1/2 cup chopped thinly sliced cooked ham 1 1/2 cups 1% low-fat milk 1 (1 lb) bag frozen whole kernel corn 1 can condensed cream of celery soup 2 green onions[...]

4 ounces bacon , sliced into 1-inch pieces 2 tablespoons unsalted butter or 2 tablespoons olive oil 2 cups chopped onions 3 celery ribs , trimmed and chopped[...]