Fajr: true dawn to sunrise.
Dhuhr: solar decline to one mithl (the two disciples) or two mithls (the cited view of Abu Hanifah), excluding the noon shadow.
Asr: the end of Dhuhr until sunset.
Maghrib: sunset until shafaq disappears, with disagreement about redness versus later whiteness.
Isha: the disappearance of shafaq until true dawn. Witr is performed after Isha and before dawn.