DIY Planetarium

June 1, 2021

article & photos by stephanie hobby

Making your own indoor planetarium is fast, easy, and can even be done on camping trips. All you need is flour, water, a plastic bag, a large bowl, magazine or newspaper, pen or other semi-sharp point, and a light source (an iPhone flashlight works great!) If you want an accurate representation of the night sky, there are many free online charts

Step 1 

First, you’ll need to start by mixing a paste of two parts water to one part flour in a separate bowl. Whisk until smooth and there are no lumps. Set the paste aside.

Step 2 

Wrap a plastic bag around a large, upside-down bowl; cut or tear inch-wide strips of magazine or newspaper.

Step 3

Coat each paper strip with paste, and run it between your fingers to remove the extra liquid. Put one end of the strip at the top of the dome, and smooth it down to the rim of the bowl. Repeat until it is covered and there are no holes. Leave it out to dry. 

Step 4 

Once the paste is completely dry, gently peel the paper bowl from the plastic bag. 

Using a pen or other relatively sharp point, poke different sized holes around the bowl. You can use a sky chart to make a more accurate representation of the night sky.

Step 5

Once you have the holes how you want them, take your paper bowl and a small lantern or cell phone flashlight to a dark space. If you are camping, this makes a great night light inside a tent. Put the light under your paper bowl to see the “stars” on your ceiling.

What’s happening?  

Notice that the smaller holes make “stars” that are harder to see. Try this in different lighting conditions. If you’re in a dim, but still lit room, can you still see the smaller, fainter stars as well? How does this concept relate to light pollution? If you’re using a lamp to light a room, try covering it with a towel so the light only points down. Does that make it easier to see your stars on the ceiling? What ideas do you have to curb light pollution? Is there anything you change at your house to reduce your family’s impact? Enjoy, and have fun! 

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