Timing of fajr prayer
Question

                If the calender table indicates 4:45 a.m. as Ishraq till what 
time can Fajr be prayed?
Thank you
Praise be to Allah.If what is published in the calendar conforms to what is actually observed in reality, then 
the answer to your question is what was narrated by Abu Huraira in the hadith of the 
Prophet 
 (peace be upon him): "Whoever catches a raka'a of the morning prayer 
before the sun rises has caught the prayer" (i.e. on time) (Bukhari).
It must be noted, however, that praying the five daily congregational prayers in the 
mosque is wajib (compulsory) for men.