People have been fascinated by the movement of stars and celestial bodies for generations. Modern planetariums present educational demonstrations that replicate this motion. Those who don't live near a planetarium can build their own mini star projector. Mini star projectors can be something as simple as a tin can with holes punched in it and a person holding flashlight inside, or something as complex as a pentagonal, automatically rotating, metal ball with a LED light inside. Building a mini star projector out of a large plastic ball can easily and inexpensively serve most people's needs.
Print a map of the stars, or draw your own map using pictures of the constellations as a reference. Poke holes through the stars on the map using a pencil for the large stars and a pin for the small stars. Tape the map to the plastic ball.
Mark the location of the stars on the ball by coloring the white paint pen over the holes in the star map. Allow the paint to dry. Remove the map. The ball should have little white dots all over it.
Drill holes in the ball using the electric drill where the white "star" dots are located. Use larger drill bits for the pencil dots and smaller drill bits for the pin dots. Cut a hole with the jigsaw in the bottom of the ball slightly smaller than the large end of the funnel.
Insert an LED light into the fixture. Slide the fixture into the funnel so the light bulb sticks out the end of the small part of the funnel. Epoxy the base of the fixture to the inside of the funnel to keep it from slipping back down the funnel.
Insert the funnel into the plastic ball so the bulb is near the center of the ball. Screw the base of the funnel to the plastic ball with the screws. Screw one side of the motor to the base of the funnel and the other side to the wooden triangle base. The ball should rest at an angle due to being mounted to the side of the triangle base.
Insert batteries, and turn on the light fixture. Turn off the room's lights. Turn the hand crank on the motor to rotate the star projector.
- Map of the stars
- Large, hard plastic ball (hollow, black)
- White paint pen
- Electric drill
- Drill bits, various sizes
- Plastic funnel
- LED bulb
- LED fixture, battery operated
- Wooden triangle base (about 1-foot tall when on end)
- Slow motion telescope drive (hand operated)
- Screw driver
Make sure not to get any epoxy on the light bulb or the area where it attaches to the fixture, so you will not glue the bulb to the fixture.
Work in a well-ventilated area and consider using a respirator. Drilling through plastic and working with epoxy can create toxic fumes.