By the heaven and Ma Banaha.
The meaning here could be for descriptive purposes, meaning "By the heaven and its construction."
This was said by Qatadah.
It could also mean "By the heaven and its Constructor."
This was stated by Mujahid.
Both views are interrelated, and construction means raising.
This is as Allah says,
وَالسَّمَأءَ بَنَيْنَـهَا بِأَيْدٍ
With Hands did We construct the heaven. (51;47)
meaning, with strength.
وَالسَّمَأءَ بَنَيْنَـهَا بِأَيْدٍ وَإِنَّا لَمُوسِعُونَ
وَالاٌّرْضَ فَرَشْنَـهَا فَنِعْمَ الْمَـهِدُونَ
Verily, We are able to extend the vastness of space thereof. And We have spread out the earth;how excellent a spreader are We! (51;47-48)
This is also similar to Allah's statement,
وَالاٌّرْضِ وَمَا طَحَـهَا