Times of Salaah

Q: Upto how many minutes before Ghurub aftab, Salatul-asr can be prayed and how many minutes before ghuroob aftaab, makrooh time for salatul asr starts?

Q: My question is about differing start and finish times for Salaah. The mosques I have near to me have different times for Salaah. For example one mosque start time for esha is 9:30pm and another is 10:20pm. If I usually pray in one mosque can I follow the timing for the other, again as an example I follow the mosque with the 10:20pm start but offer my esha prayer before that as the other mosque clearly starts at 9:30pm. Is this permissible?

Q: What is the reason behind prohibition of Salaah during Tulu' (Sunrise), Zawal (Zenith) and Ghurub (Sunset) period of the sun?

Q: I am giving exams when I depart from my home. It's Zohar time so I offer it but when I arrive at my home, it's maghrib time so can I offer Asr Salaah at Zohar time or at Maghrib time?

Q: A radio station broadcasts Surah Waaqiya immediately after the Magrib Azaan. Is it permissible to delay performing the Maghrib salaah by about seven minutes and listen to the recitation of the Surah first?

Q: What is the last time of asr? As in how many minutes before maghrib can asr be read?

Q: Sometimes when I wake up for fajr, I wake up a little late and the time of fajr is nearly on its end. So in that circumstance can I pray only fardh? Because if I pray Sunnah, then to complete my fardh I have to rush my prayer.

Q: As I live in a city and because of the buildings, I can't always see the sky openly. How can I determine that time when salah is forbidden? Is there any trustful program to use, do you know one? I hope it is the one that shows time as salah calendar as I don’t always have wifi on at home? And also, if I didn’t make my fard yet and the forbidden time started, can I still make my salah if I see that due to some reasons I will miss it - like toilet is busy, water is going to be off, etc? How sinful is it to make salah at this time? Also, if I start salah some minutes prior to this time and ended it when this time has started, do I have to repeat my salah?

Q: Is it okay to offer Asr Salaah in Shaafi'ee time rather than Hanafi time? (I am a hanafi)

Q: Is it true that Esha time sets in one hour after Maghrib Salaah and is it permissible to perform Esha one hour after Maghrib Salaah?