Can You Identify These Apples?

My parents don't pay much attention to plants and trees and flowers. Thus, after their landscaper told them what kinds of fruit trees he had planted in their yard, they promptly forgot what he said. This left me to try to guess what we're growing based on the fruits I pick.

Some were easy, like the unmistakable Asian pears. Others have stumped me, like the firm green apples that ripen every August. At first I assumed they were Granny Smith, but then I read that Granny Smith apples are late-season ripeners. These apples are most definitely early ripeners, looking ripe in early August every year. The flesh is tart and a bit dry... but that could be due to lack of water. :-) Here's a picture of my first harvest - any ideas as to what kind of apples these could be?