Conditions for the validity of Salaah

Q: I have heard recently that some Fuqahaa have permitted  a certain amount of degrees leeway on either side when facing the qibla. Could you please elaborate on this?

Q: Nowadays we use a prayer time chart but we hear from Darul Uloom Deobond that this is not accurate and they quote a hadith that for calculating the time of Esha salah we have to calculate the time difference between the rising and setting of the moon in every 3rd day of the current lunar month. Suppose the difference is 1 hr 47 minute then Esha will be 1 hr 47 minuets after Magrib for the same complete month and the process will continue. What is the truth?

Q: I will be sailing on a ship from Cape Town to Sydney in Australia. Since I will be losing time going East. How can I calculate the time for Fajr?

Q: I would be leaving my country and will travel in a ship as I got selected for the Navy. I want to know on what timings I can perform Salaah on the ship as there would be no Adhaan. So, please answer on what timings to pray Salaah while travelling on a ship and if I miss Friday Salaah, how can I repent.

Q: For Sunnah Salaah does one have to make it with the niyyah of the Fardh Salah one is praying it for? E.g making niyyah that I am performing 2 Sunnah of Zuhr?

Q: How is it to perform salaah wearing a T-shirt?

Q: We are Hanafi. If I am leading the salaah at home, and my wife wants to read salaah behind me. What intention should I make? E.g. during ramadhaan, I read Esha, Taraweeh and Witr. Do I need to make an intention for each two rakaats that she is behind, or can I make an intention once for Esha and let it count for all. How must the intention be made? Verbally, in the mind, or just a realisation that she is behind me?

Q: I follow the Hanafi fiqh and the time for Asr salaah is at 6pm but I live in a city in which we only have one musjid and they read asr at the Shafi'ee time of 5:15pm. Is it okay for me to read asr with Jamaat according to the Shafi'ee fiqh even though I follow the Hanafi fiqh?

Q: I have heard that Salaah is more makrooh when our trousers (pants) are folded up during Salaah? Please advise with the reference from Hadith.

Q: Is one allowed to change one's niyyat of Salaah (during salaah) from Fardh to Qadhaa?