It can be prayed anytime.

Among the best times probably would be the last third of the night

What is the most correct and appropriate time to do Istikhara?

Prayer | March 25, 2014 6:37 pm
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Suppose there is a 4 rakah congregational prayer going on and if I come late and join the prayer and I missed 3 rakahs with the imam. How many tasahuds do I have to sit when I make up the missing rakahs after the imam has said the salaam?
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Today I woke up late and missed Fajr congregation. So I prayed at home the Fard prayer only during sunrise. Is my prayer valid? I found one hadith which states something like, no one should pray during sunriseI prayed Fajr at that time based on the hadith that whenever a person wakes from sleep must pray. Please clarify.