Session 3B: Making our Model of Orion

There are only seven stars in our model. We'll model the two shoulders, the two legs/knees, and the belt but skip the other stars. Otherwise it gets too crowed. To do this, you'll need the following items:

  • 7 beads. I used all black pony beads in my original model because they are easy to see, but you can use colors, too. Rigel is a blue giant star so for one copy I made, I substituted a pale blue ball from a pony-tail holder (uhm, this destroys the pony-tail holder, okay?). Betelgeuse is a red supergiant, so I substitutded a red ball from another pony-tail holder.
  • Hot-glue gun. This will be used to attach the beads/balls to the top of the skewers. And, of course, glue sticks.
  • 7 bamboo skewers. These are the things you use for making shish-kabob on the grill. They're thin, strong, and flexible. They'll have to be cut to the correct length.
  • A piece of styrofoam sheet, about 6x12 inches to form the base. Any old scrap you have from packaging will work fine.

The attached PDF has two templates, one for cutting the bamboo skewers to the correct length and another for how to position them onto the base. First attach the template to the base. You can tape, glue, or just pin it in place. The template has to be placed diagonal onto the base or it won't fit. You can also trim the template to eliminate any wrap over the edges.

Next, for each star, cut a skewer to the correct length, glue a bead to the top, stick the skewer into the corresponding spot on the base template/styrofoam. I cut my skewers so as to leave the pointed edge attached which made it easier to poke a hole through the paper, but it really doesn't matter which end you cut. Do try to put the skewers in so they stand straight up from the base.

Viewing the Model

When you're done, you'll probably be thinking this doesn't look much like Orion. Well, it won't unless you put your eye in the correct vantage point so you are looking at the "stars" from the position of Earth. If you've followed the template on this page, then that place is about 8-12 inches from the edge of the base in the direction where all the lines drawn on the base converge. You want to try to place your eye at the height of the belt stars. It works best for me if I only use one eye. Then I have to move the base around a little to find the right spot where the three belt stars line up. Once I have that, I can see the shape of Orion.

The real "fun" is when you move your head away from that spot. This is like flying around in space and viewing the stars of Orion from different places where it really doesn't look anything like our familiar constellation. The point of the exercise is that the constellations we are used to seeing are really just accidental alignments that our imaginations turn into pictures.


I've also added a model template for the Big Dipper which we did not use in class but which I later used at the Northeast Astronomy Forum (NEAF) 2008.  It works the same way and the supplies are the same since there are only seven stars used.  This model is, however, somewhat more user friendly since many of the stars are at a similar distance making the placement of your head a little less critical.


These models are not to scale!  In order to make for comfortable viewing, I cheated on both of them, but especially on Orion.

With Orion, the distance ratio between the farthest and the nearest stars as about 6:1.  So if I try to put them all on a single 6-inch by 12-inch foam board, my eye needs to be about 2-inches from the front of the board to be in the same location (to scale) as the Sun's position.  At that distance, I can't focus on the closest bead at all and the view is very uncomfortable.  So I kept the same relative distances (sort of) and added a large offset (1000 light years!) effectively making Earth much further away.  But that creates another problem.  If I use the same angular separation, the stars begin to cluster together very tightly.  So I increased the angles by a constant scale factor of 3 to spread them all out again.  This makes it possible to put your eye about 8-12 inches from the front of the board and get a nearly correct visual view of Orion while still getting a sense of the 3-D structure.

I did the same thing for the Big Dipper, but the distance offset was 300 light years and I actually shrank the angles by 2/3 to fit them on the board.