By the star when it descends, (53:1)

Almuntakhab Fi Tafsir Alquran Alkarim

I swear by the celestial body when it goes down to make an apparent descent toward and below the horizon

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(53:1) By the star when it sets: *1

By the star when it descends, meaning

*1) In the original the word "an-najm"has been used. Ibn `Abbas, Mujahid and Sufyan Thauri opine that it implies the Pleides. Ibn Jarir and Zamakhshari have held this same interpretation as preferable, for in Arabic when the word an -najm is used absolutely it usually implies the Pleides. Suddi says that it implies Venus; and Abu `Ubaidah, the grammarian, holds that here the word an-najm has been used generically so as to express this idea: "When the day dawned, and the stars set." In view of the context we are of the opinion that this last interpretation is more preferable.
 

By the star when it descends, meaning in Urdu

قسم ہے تارے کی جبکہ وہ غروب ہوا