salaah time

Performing Salaah in the forbidden time

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?

Delaying the witr Salaah

Q: My question is about witr Salaah:

1. After performing Esha Sallah at 8.00pm, can I delay my Witr Salaah till 11.00 pm(my sleep time)?

2. Can I combine Tahajjad and witr at the above mentioned time?

3. What will be my last Salaah before I go to sleep, Tahajjad or witr?

Performing fajr Salaah at home if one fears missing the Salaah

Q: For whatever reason which Allah (Ta'ala) knows best I woke up for fajr salaah a bit later than usuall i.e. within permissible time but not enough to make it to the masjid as I felt I could miss the Jamaah and fall within an impermissible tome. I commenced with salaah and performed a short but not hesty salaah with Jamaah at home. I had completed salaah and tasbih* and dua by 04:35am- 20/12/2015-durban. Latest Jamaat commencment time in locality is at 04:25 (Masjid is Al-Hilal)- did my salaah fall within the permissible time and was my decision to perform salaah at home with jamaat at home valid on grounds that I could have missed salaah and permissible time completely had I driven to the masjid. Note that we follow the Shafi'i Madhab so the duration of salaah included dua e qunoot which was incumbent on me as the imam leading salaah.