Constellation in a Jar Nightlight DIY

I used to live in the country where I could look up at night and see a dark blanket spotted with light. There were so many stars I wondered how people used to identify constellations. Then, in 1994, I received a Box of Stars (not an affiliate link) book and kit. Since then I have enjoyed making a constellation in a jar that suits the books I’m reading, the mood I’m in, or just because I want to see it as I drift off to sleep.

Here’s how you can make one.

Supplies needed:

  • A clear jar, preferably one with an opaque lid.
  • A tap light (and batteries for it)
  • A sheet of aluminium foil
  • A ruler or measuring tape
  • A needle
  • A Sharpie
  • A template (optional)


Step 1: Measure the jar’s height and inner diameter. You’ll need these numbers for fitting the aluminium foil.
Step 2: Fold the foil according to the height of the jar.
Step 3: Calculate the circumference (C = 2·Pi·r)
Step 4: Fold the foil for the circumference, then check the fit before cutting off the excess.
Step 5: Use a constellation template or free-hand draw where you want your stars to be.
Step 6: Poke holes in the foil to let the light shine through.
Step 7: Put the foil and the tap light into the jar.
Step 8: Make some hot cocoa and enjoy.

In the video below I demonstrate how this is done in a little more detail.

If you or you know someone who loves astronomy, you should check out this month’s giveaway. It’s an astronomy game that really challenges the astronomy fan to reach for all the bits of random knowledge they so happily accumulated but rarely get to show off.


Learn more about the game and enter the drawing
Game details and the drawing can be found here:

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