This is my first artichoke I've grown, so I'm not sure how long to wait before it's ready. The bud's still pretty small, but the leaves do seem to be separating a bit at the base, so I thought maybe it needed to be picked now/soon regardless of size...?
With my limited experience, I would say pick. The structure should generally be tight when it is time to pick. You fruit looks prime to me.
For future reference, you want to pick before the center opens out - the spreading of the lower petals is your warning. If you let the third tier of lower petals open, then the center is about 1-2 days behind them. And have you ever eaten them with a white-wine and parmesan sauce? Yummers!
Great tip - thanks, Lorax! I'll do that for the next ones that are developing. This one was tasty, but evidently could have waited a bit, because the choke had not developed yet. (Though that made it easier to eat!) And that white wine Parmesan sauce sounds WONDERFUL!! If you have a recipe, do tell!