Remove as much furniture from the room as possible. Cover the floor and any remaining furniture with drop cloths. Tape off the surrounding walls where they meet the ceiling with masking tape to prevent drips and smudges.
Place a ladder near the wall and climb high enough to comfortably reach the ceiling. Use a paint brush to edge the room with about three inches of paint, working inward from the point where the ceiling meets the wall. Select a shade of blue that complements the other decor in the room. Everything will look darker with the lights off so even an airy sky blue will transfer well to night time. For a more dramatic effect, use an even darker shade of blue.
Fill in the center of the room with a paint roller attached to an extension handle. This will allow you to stay securely on the floor while you paint the majority of your ceiling. Add a second coat if desired. For those with a textured ceiling, several coats may be necessary for even coverage. Wait at least 24 hours for this paint job to dry before proceeding.
Turn off the lights and use a projector with star transparencies or toy planetarium to shine constellations on the ceiling. Follow this guide to create a scientifically correct representation of the night sky.
Use a medium-sized synthetic bristle paint bush to create your stars. Dip the brush in glow-in-the-dark paint and press it against the ceiling so the bristles fan out in all directions. This will create a realistic starburst that’s fuzzy around the edges. Each star will be slightly different since this effect creates somewhat random results. Lift the brush straight down from the ceiling after creating each star.