It is Impermissible to Perform the Prayer while Doubting the Beginning of its Time
31-7-2022 | IslamWeb
Question:
NEED URGENT ANSWER: My local mosque began to pray the ‘ishaa’ prayer at 10:15pm here in Britain (UK) and I recently saw the existence of the red afterglow still in the sky from my garden at 10:19pm, which isn't visible from my room window. I cautioned the imaam of the mosque on this and he said that the white light exists till fajr. I clarified to him that I'm referring to the red afterglow and not the white light/thread. He responded by saying that there's no difference and stated that the scholars have ruled a 60 minute calculation after maghrib to determine the starting of ‘ishaa’. I told him that one of the scholars of Saudi said that there is no evidence for that, to which he responded that they have their evidences. He mentioned that if you're allowed to combine, then why cannot you pray after a little after maghrib. He mentioned that some people have examined from the 19th floor of a building and examined the changing of the sky and noted every change down, and they concluded that the white light stays till fajr. But what is not convincing me is the fact that my brother-in-law and I saw the red afterglow with our naked eyes whilst they were praying ‘ishaa’ (because we quite often go to another mosque that prays ‘ishaa’ at 11:00pm) and later on I saw the red afterglow faded away and I saw light but I think that is the light of the street lamps and was reassured by my sister and brother-in-law that it is. Should I continue to pray at my local mosque and if not, then what should I do regarding my previous ‘ishaa’ prayers that I prayed with them before coming to realise the existence of the red afterglow being present at around that time, bearing in mind that I always had a doubt about the time in which they pray ‘ishaa’ and bearing in mind that I do not know how many ‘ishaa’ prayers I prayed with them outside the correct time and for how long this has been happening for, since I have been going to the other mosque quite often?
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
First of all, we cannot authoritatively determine the beginning of the time of the ‘Isha prayer in your country because we do not know the reality of the situation and when the red twilight actually disappears.
However, what we can authoritatively confirm is that what the Imam said regarding the time of ‘Isha that it begins 60 minutes after the Maghrib prayer is not true.
For more benefit, please refer to Fatwa 307522.
Also, what the Imam had said that it is permissible to pray the 'Isha prayer a short period of time after the Maghrib prayer as a way of analogy of combining between them is also not correct.
Because combining the prayers is invalid unless there is a sound reason for combining them.
Combining the prayers without a sound reason is one of the major sins as stated by the Salaf (righteous predecessors).
The rule here is that it is not permissible to perform the prayer while doubting about the beginning of its time, and it is not permissible to perform it unless it is certain that its time has begun or that one predominantly thinks so.
The time of the ‘Isha prayer begins when the red twilight starts to disappear; therefore, it is not permissible for you to pray in the mosque, where you doubt that they do not pray on time. So you have to wait until you are sure or you predominantly think that the time has of the prayer has started. You can rely on one of the trustworthy calendars about the timing of the prayer in your country.
You should continue to advise the brothers in this mosque and to clarify to them that it is not permissible for them to start the prayer before it is certain that its time has started, or before they predominantly think that its time has started.
As regards the ‘Isha prayers that you had performed previously (in that mosque), then the prayers that you had performed while doubting about the beginning of their time, you have to make them up. If you do not know the exact number of those prayers for certain, then you should estimate them and make them up until you believe that you are acquitted from sin.
Allah knows best.