Salaah

Going late to the Musjid for zuhr Salaah

Q: I am at home and the zuhr prayer jamat will soon start in the masjid and I have only a few minutes to perform my 4 sunnats. If I perform the sunnats before I leave for the masjid, I will miss the beginning of the jamat (I will catch the last 1-2 rakats). Should I do this, or should I instead leave early to the masjid and pray the 4 sunnats after the fard, thus catching the jamaat from its beginning?

What is twilight

Q: What is the definition of twilight? In beheshti zewar English it says the redness on the western horizon, when that disappears then esha time comes in. However some kitaabs mention the twilight according to imam Abu hanifa as the whiteness after the redness. Which is correct. Why is it mentioned as redness in the beheshti zewar, would this not make our esha time early like the shafis etc.