I'm making a small solar system, complete with a star and planets. I want the star to appear in the renders, but using it as a light source makes the renders much worse because its light is noisy. I would much rather use a point light as the light source, but I still want the star to be visible in renders. Is there a way to make it so that the light from the star is still visible in the camera, but it doesn't affect the rest of the scene? I'm using Cycles.
If you go to the Object Properties tab on the emission object, there under Visibility > Ray Visibility you can disable everything except for Camera.
This way the emission object will be visible but not affect the scene in any way, it will shine no light onto objects, it will not be visible in reflections etc. You can even put your point light into the center and the emission object will not block the light, so you can use the point light as light source for your planets.