Hello Richard. There are currently two ways to do this in 3D.
1) You can retrieve the 3D positions of the stars you are interested in and literally add 3Dpoints that are colored and scaled to represent brightness. This might be difficult when combined with the use of ViewVector since having objects that are really close to the camera like the Moon and also really far away objects like the stars might be really tricky to keep all of that rendered. Might have to adjust the ViewRange option to include those new objects. Supports in all things at true scale might be hard for the rendering system. Might be able to reduce the true distance so they are much closer, but still behind everything in the scene
2) You could add a Sphere to the scene that is textured that shows the stars you want. You would need to orient the Sphere and rotate it properly using Astronomy`AstroOrientationMatrix. It would need to be big enough to enclose all objects in the scene. ViewRange might need adjusted, Lighting might need tweaked. Texture might need to be really high resolution to look as sharp as real 3D points.
