If you start Shacharit Shemoneh Esrei during zman, and finish it out of zman, what is the halacha? For example, if you are davening towards the end of the 4th halachic hour, and you start Shemoneh Esrei just before the end, but finish after the end of the 4th halachic hour, does it still count as the full mitzvah?
See the Aruch Hashulchan is siman פט who asks this point exactly. He brings a Tos' who deals with the question of how Bilaam could have cursed the Jews in the one split second during which God gets angry. In one of Tos' answers he says that if he started the curse during that moment and continued afterwards it would still count. The Aruch Hashulchan suggests that this should also apply here. But, it should be noted that other poskim are strcit on the point.