Is it permissible to perform the night vigil prayer (Salat Qiyam al-Layl) after the break of dawn, taking into consideration the time of the Fajr adhan in Istanbul, the delay in establishing the congregational prayer (Iqamat as-Salat), and the difficulty of combining Qiyam al-Layl, seeking forgiveness in the pre-dawn hours (Istighfar fi al-Ashaar), and praying Fajr in congregation before starting the morning work?

Praying after Fajr (dawn) is not considered part of Qiyam al-Layl (night vigil prayer). Many scholars, such as the Hanbalis, have prohibited it, except for the two rak'ahs (units of prayer) of Fajr. The time for Qiyam al-Layl begins at the start of the night. It is permissible to perform it early and then sleep, or to perform it during the pre-dawn hours (Sahar) and sleep a little before the iqamah (call to commence prayer). The matter depends on what best serves one's interest and allows for reconciliation between praying in congregation and work circumstances.