Answered by Ustadh Torab Torabi
I know that the time for suhoor ends 10 minutes before fajr. Does this mean that the time for Isha ends 10 minutes before fajr as well, or can you pray until the start fajr (proper)?
The time of Isha is from the end of Maghrib until the beginning of Fajr. Thus, if a person were to complete Isha prayer before the entering of Fajr, the prayer would be valid, yet disliked (makruh).
It should be noted that to make it a habit to pray Isha minutes before Fajr would be prohibitively disliked (makruh tahriman) and against the Sunna.
The time for suhoor is actually valid until the moment Fajr enters. It is sunna to delay suhoor as much as possible without becoming fearful of accidentally breaking the fast. (10-15 minutes).
Jazak Allah Khayr.
And Allah knows best,
[Ustadh] Torab Torabi
Checked and Approved by Shaykh Faraz Rabbani