Answer
(Fatwa: 719=679/B)
According to Hanafi Fiqh, the time of Isha Salah starts after disappearing of Shafaq Abyaz (white twilight). But, some scholars of Hanafi Fiqh like Imam Abu Yusuf, Imam Muhammad are of the opinion that time of Isha Salah starts after disappearing of Shafaq Ahmar (red twilight). This opinion has been narrated by Imam Abu Hanifa as well. So, in view of the narrowness in time in a state of exigency you can pray Isha Salah in Ramazan (in June) after Shafaq Ahmar so that there is no problem in praying 20 Rakat Taraweeh. In a state of exigency it is allowed as praying Asr Salah is allowed on Misl-e-Awwal (when the shadow of any object is equal to it along with its original size).
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband