What would the Halacha be with purchasing a home planetarium which is basically a slide that goes into a projector that projects the image onto the wall and ceilings. On the one hand it’s very realistic so may be compared to a 3D image or better but on the other hand it’s not really any image as it’s only projected on the ceiling but doesn’t last permanently on the ceiling. Also it’s purpose would be partially for relaxation as well as studying the night sky and knowing how to identify the Mazalos etc.
It is permitted, because there aren’t really images or a real picture of the stars on your ceiling, rather it is light that is being projected on to the ceiling to give such an effect. This would be similar to making a crescent shaped shadow with your fingers on the wall. That isn’t considered making an image, therefore it is permitted.