Time for Tahajjud?
The time for Tahajjud is the same as the time for Isha; Tahajjud prayer can be offered anytime after the Isha prayer until the time for Fajr begins. There is a narration by Al-Haythami: "Whatever prayer is offered after Isha is Qiyam al-Layl, meaning Tahajjud." Keeping in view the practices of the Prophet, the jurists have written that if one wishes to spend one-third of the night in Tahajjud, the middle third of the night is most virtuous, and if one wishes to offer Tahajjud for half the night, it is most virtuous to spend the latter half in Tahajjud. (Kitab al-Fatawa / Vol: 2 / Pg: 118)