I will attempt to give a short answer to this very tough question which require both knowledge of history of photography and science. I don't claim expertise in both subjects. Given the fact that astrophotography reached the masses later than photography, one may look for answers through the history of photography.
If astrophotography belongs to the genre of
documentary photography, it must provide a straightforward and accurate representation of objects and events.
But...
Contrary to popular belief, any photograph is a subjective representation of reality. Even the act of seeing a photograph is subjective, since
our eyes are poor optical instruments and require the intervention of the brain to conceive the image.
With that in mind, the question becomes, "what we want to achieve by presenting the viewers an astrophotograph?". Some possible answers may be:
To attempt a faithful representation of an astronomical event.
To educate the viewer about astronomy/astrophysics and the scientific method.
To demonstrate our processing skills.
To show off our expensive equipment.
To earn prizes in well-established contests.
To earn "likes".
Depending on the answer(s), one chooses where the line is drawn.