Not in the summer Hank. Sometime between Nov and March.

Yup, wait until late fall or early spring during its dormancy. Trimming those vertical branches will allow more light to get into the productive parts of the tree. I see in the photo a few branches growing downward that can be trimmed too. If you see any suckers they can be trimmed right now, you don't have to wait. Looks like that tree is working hard for you, you're going to have a great yield of apples.

Thanks for the replies, I knew that was the rule but they seem to be longer than in years past.