Star reduction

Within the "Sky" module of Nebulb there is a specific functionality to apply a star reduction/attenuation:

Star reduction

With the "Reduction" slider it is possible to dim the stars so that they are less visible and the other celestial objects (e.g. the nebulae in the galactic centre of the Milky Way) stand out much more.

Below is an example of the result you can obtain using the star reduction functionality in Nebulb:

Image showing all stars at their original intensity levels

Image in which the stars shine less brightly because the star reduction has been applied at 50% intensity

Image in which the stars are hardly noticeable after having applied the star reduction to the maximum (100%)

Why do so many stars appear in Nebulb?

The fact is that the sky is full of stars, although due to light pollution not all of them are visible in the photos (unless captured in an area with very low light pollution).

However, by applying light pollution reduction in Nebulb, everything underneath (nebulae and stars) is brought out. This is why the difference between the level of stars that can be seen in the images (before and after light pollution reduction) is so large, which is why this star reduction tool can be particularly useful.

You can see an example of this below:

Region (at 100% zoom) of one of the original RAW images where stars can be seen, but not too many.

Same region as above, but after stacking. As the noise has completely disappeared, many more stars can be seen.

By applying light pollution reduction the light offset that covers the sky disappears and therefore everything underneath (nebulae and stars) stands out much more, which is why the number of stars may now seem excessive.

By applying a star reduction (100% in this example), the stars are greatly reduced, making them stand out much less in the image, thus giving more prominence to the nebulae in the sky.

Please note the most characteristic stars

The star reduction, like many other aspects in photography, is something very subjective, since there are people who like images with many stars and others who prefer them with very few. Precisely because of this, in Nebulb you can apply the star reduction gradually (so each user can set the level of reduction that he/she likes the most for each photography).

That said, one thing that is usually taken into account when applying star reduction is that there are very characteristic stars that, in the case of not appearing in the image (or being very dimmed), can generate a somewhat strange sensation in the observer.

An example of this are some of the stars in the galactic centre of the Milky Way, such as those in the Lagoon nebula or in the Antares region.

Image of the galactic centre of the Milky Way without applying any star reduction. The Lagoon nebula (left) and Antares (right) are highlighted in red.

Same image as above, but applying a reduction of stars to 100% intensity. In this case, both the stars in the Lagoon Nebula (left) and the stars in the Antares region (right) have been very faint and are practically not visible, which may create a somewhat strange sensation for the observer.

However, by setting a star reduction level below the maximum (70% in this case) a good balance is often achieved between a large star reduction and keeping the most representative stars visible.