By the Star when it goes down,-
Najm is interpreted in various ways. As most
commonly accepted, it means either a Star generically,
or the close cluster of seven stars known as the Pleiades
in the Constellation Taurus, which the sun enters about
the 21st of April every year.
In mid-April, or a little later, the beautiful cluster would
set just after the sun, after having gradually ascended
the sky in the winter months. In late May, or a little
later, it would rise just before the sun. In its western
aspects, it might be considered a spring constellation.
To open-air nations (including the Arabs) whose climate
usually presents starry skies, this is an object of great
interest, and many folklore tales gather round it.
When so glorious a cluster is content to bow down in the
horizon and merge its light in the greater light created
by Allah, it becomes a symbol of humility in beauty and
power before the Most High. Whose revelation discloses
the summit of beauty, power, and wisdom.
Hawa in the text may mean either “goes down (or sets)”
or “rises”. Whichever meaning we take, it makes no
difference to the interpretation given above
Yusuf Ali, Abdullah. Translation and Commentary of the Quran. (surah 53 verse 1. Quran Arabic with English Translation & Commentary (Tafsir) by Abdullah Yusuf Ali, Free Download (quran4u.com)