A few years ago I decided we needed a planetarium at my school. I quickly realized that a planetarium was way outside the budget. So, I decided we would have to build one. Another teacher and I collaborated to challenge our high school science and geometry students to design and build a massive geodesic dome that we could turn into a planetarium. We were awarded a grant from the Billings Education Foundation to buy supplies and this is what we came up with:
While doing research for the project I found information about building large scale geodesic domes at Desert Domes, which proved to be a great starting point to figure out dimensions of different frequency domes.
Students then scaled up the dimensions for a 4V (frequency) dome. This type of dome required 6 pentagons, 5 full hexagons and 5 half hexagons (information below). We chose this configuration because it meant we only needed to cut out two different types of triangles: Pentagon triangles with sides labeled AAB and Hexagon triangles labeled BCC (information below). We bought a pallet of corrugated cardboard with white on one side and cardboard brown on the other, made some templates and began cutting triangles.
Initially we had planned to use extra large 1 inch binder clips to hold the structure together but this proved to be fatal two times. The entire dome collapsed as binder clips slid off the cardboard and went shooting across the room. With two fails under our belt, we had to rethink our plan.
Eventually I found Mr. McGroovy Cardboard Rivets online, and they proved to be just the tool needed to get our massive dome built. It takes a team of people to hold, rivet, add a triangle, hold, rivet, repeat, but it is well worth the effort!
Materials Needed to Build a Cardboard Planetarium and Projector
Cardboard
We purchased a pallet of double walled, corrugated 4ft x 8ft sheets. Brown on one side, white on the other. Check with local paper or cardboard box suppliers or order online at...
The U-Line sheets were recommended by Bennie G who build a dome with these plans. They purchased 100 40x48" sheets which allows about 10 sheets for mistakes.
Cardboard Rivets - minimum of 4 boxes of rivets recommended (Alternative Box Rivet Option)
DIY Planetarium Projector
Originally we'd planned to make a box with holes poked in it and a light inside to project stars on the inside surface until I found Paul Bourke's site titled "Dome Projection Using a Spherical Mirror". I immersed myself into Paul's work and ultimately came up with a design for a planetarium projector that would work for our design. I bought a of couple inexpensive plastic shelves (find them here) and cut the supports so the spherical mirror (find it here) and the projector would sit at the correct height.
We learned that when it comes to digital projectors, you get what you pay for. We started with a budget Epson projector that worked well (similar models here) but later switched to a Casio DLP projector (similar models here) with much higher resolution. Of course, with greater resolution comes a higher price so go with whatever you already have or whichever model you can afford.
That was all it took! The design and concept worked magically and we saved about $10,000 by making our own!
Instructions for how to build a planetarium projector are in the YouTube video (click here)
Planetarium Movies
By chance I happened to find that Discovery Dome and ePlanetarium make some of their professionally produced planetarium movies available to educational institutions for only the cost of the DVD and shipping! You can purchase these amazing planetarium videos at the Space Update website!
Streaming ePlanetarium from YouTube
Another option is to stream the ePlanetarium videos directly from YouTube, although according to licensing this can only be used for educational purposes and you cannot charge anyone to view them. Visit the ePlanetarium site, click on a video you are interested in and click "View Widescreen", this will bring up a warped version of the video that will play on the projector setup described on this page.
Stellarium
No planetarium, even one made of cardboard, is complete without a way to project an accurate night sky to gaze skyward and enjoy the stars. So, I downloaded Stellarium, a free, open-source astronomy program. It is a spectacular program and even has folklore constellations pre-loaded in the program so you can teach kids about constellations from cultures around the world. Download it even if you don't have a dome - it is amazing!
Solar Walk (App)
Solar Walk has several built in features that allows you to tour the solar system as well as other features of the Universe. It includes tours with narration and has short videos that help you customize the learning experience for whomever is in the dome. Just plug the tablet or phone directly into the projector and let the learning begin. (Get it for your device here: Android / Apple)
Click here to watch:
Craig visits with the crew at Montana This Morning on CBS (KTVQ) about the planetarium geodesic dome and takes them on a field trip to Billings Senior High so they can experience it in person.