Place bacon in soup ot ant sautee over med-low heat until fat is rendered and it starts to crisp, 10-15 minutes.
Meanwhile, slice kernals from corn cob and reserve both.
Once bacon is ready, pour off all but 2 T of fat, leaving bacon and drippings in pot.
Add the onion and celery and cook until slightly browned and tender, 10 minutes or so.
Add corn cobs, milk and potatoes to pot, making sure to fully submerge the cobs in the milk.
Bring to a boil, then reduce to simmer.
Cover and simmer for 10-15 minutes or until potatoes or tender, then remove cobs.
Add corn kernels, salt and pepper and gently simmer until corn is tender, about 5 minutes.
Remove about 1 and a half cups of solids from soup and puree until smooth.
Add puree back to soup with the butter and let stand until butter is melted, then stir.