Fatwa ID: 04630
Answered by: Mufti Eunus Ali
Assalamu Alaikum. Hazrat, if one is performing Tahadjud, and the salah is completed after the point of Fajar adhan has commenced, is the Tahajud salah still acceptable?
In the name of Allah, the Most Gracious, the Most Merciful
Any optional salah which is initiated during the latter part of the night and during the course of the prayer Fajr salah time enters; it is superior to complete that optional prayer. Insha Allah the salah will be accepted and will not have to be repeated.
Only Allah knows best
Written by Mufti Eunus Ali
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham
 Al Fataawa Al Hindiyyah, Volume 1, Page 59, Darul Kutubul Ilmiyyah