Bright colored dots in a long-exposure photograph may be sensor noise rather than stars, but brightness alone cannot distinguish them. Compare neighboring original frames, check whether the dots stay at the same pixel locations while the scene changes, and protect genuine small lights. Correct only confidently identified defects; an AI-generated star field is a different creative image.
Separate fixed dots from the photographed scene
Use originals at the same orientation and scale. If the camera was recomposed, a real star or distant lamp normally changes its position within the frame. A suspicious sensor-related dot may remain near the same pixel coordinate. If the camera stayed locked on a tripod, position alone is weaker evidence because both the scene and sensor pattern can remain stable.
Compare color, shape and neighboring detail, then consult another exposure if available. A tiny star can also be colored, and a saturated point light can be only a few pixels wide. Do not remove every isolated red, blue or white point simply because a noise-reduction preview makes it easy to select them.
Work on a rendered copy with a limited scope
First develop the RAW file without exaggerating sharpening or shadow lifting. Keep the camera original and its processing settings. On a separate copy, mark a short list of suspect coordinates and apply a tiny local correction. Check that a repair did not smear a nearby star trail, branch or horizon.
Nikon's long-exposure-noise-reduction documentation describes reduction of bright spots or fog and notes an additional processing wait for that camera. It is a capture setting, not evidence that an uploaded image editor has recovered missing astronomical detail. Other camera models have different options; use their own manuals rather than copying one universal setting.
A hypothetical harbor example
Imagine two night photographs taken after a slight camera pan. Several harbor lamps move horizontally in the second frame, while a magenta point stays close to the same sensor coordinate. The photographer flags that point for review. A nearby yellow point moves with the lamps and remains protected.
This comparison is an illustrative diagnosis, not a confirmed measurement. If there is only one exposure, uncertainty is greater. Preserve ambiguous points or make an explicitly edited presentation copy instead of claiming that every removed light was a sensor defect.
Avoid global cures that remove the subject
Strong whole-image noise reduction can soften stars and fine texture along with unwanted dots. Repairing a handful of defects locally may be preferable. If thousands of points or broad colored fog obscure the scene, return to RAW processing or consider a new capture; a few cosmetic patches are no longer an adequate solution.
For an Imagild creative treatment, start with the accepted corrected copy, then check whether the chosen Skill changes the sky intentionally. Keep the documentary original separately.
Acceptance and future capture
Inspect the repaired export at 100 percent and at its intended display size. Require intact real lights, no dark pinholes where dots were removed, and no invented constellation. For future photographs, test the camera's supported long-exposure options before an important session and allow for their capture workflow. Sharper-looking generated stars should never be presented as evidence of what the camera recorded.