These are some quotation from the article.
But since 39:5 states that the day is rolled onto the night, then by definition part of the night will have some daylight in it
I agree that there is a gradual movement into night. But it seems that the article uses this information to conclude that at sunset night begins and day ends. I have a different interpretation. As long as there is light in the sky day did not end. But this does not mean that night has not began. the above verse can best understood in the light of other verses. Such as the one you mentioned
And a sign for them is the layl, We strip/peel/remove from it the nahar, whereupon they are those in darkness. [36:37]
Where it is clear that night and day can happen at the same time. For a short period.
It is important to note that in the article the verse is translated as
“Another sign for them is the night: we “naslakh” (gradually extract) the
daylight therefrom, till they become in total darkness.” 36:37
In arabic, the word is nahar which should be translated to day. Not daylight.
The second indication to offer us the correct definition of the night can be found in the following verse:
“You shall observe the Contact Prayers (Salat) at the "tarafai” (two terminals) of the day .......” 11:114
The argument is that the two terminals must represent a defined point.
The only specific and defined points in time around the ends of the day are sunrise and sunset
My opinion is that total darkness after sunset and before sunrise can be 2 terminals. (not for 1.5 hours but at the point or period of total darkness only)
We also read in 11:114 a reference to the “Zulaf al-layl”. This phrase translates to the “near parts of the night”. What are they near to?
Here I did not understand what is he trying to say. I think the verse is clear.
Finally, and to seal this issue, we are given Quranic words in Sura 91 which provide conclusive proof as to the timing of the “Nahar” (day) and the “Layl” (night). The following words speak about the sun:
[91:1] By the sun and its brightness.
[91:2] And the moon that follows it.
[91:3] And the "nahar" (day) that reveals it.
[91:4] And the "layl" (night) that covers it.
Here it depends on how you take the meaning. Either sun by itself is what is revealed and covered or the sun and its brightness.
Maybe the the biggest difference between my understanding and the article is that I believe that night and day as I said earlier overlap. While in this article when day ends night starts and vice versa.