Almost impossible for a photograph of the sky to be without stars but they should not overpower the main subject of the photograph, if that is a galaxy or a nebula. However, when stretching the data to reveal detail in the galaxy or nebula stars generally enlarge too and detract from the nebula or galaxy, the centre of the photograph.
There are several ways to keep the stars small enough and this one requires separating the stars from the main subject of the photograph. It works well with galaxies and where nebulae are not also full of stars.