The Southern Cross (Crux) is an iconic feature of the southern sky. It is my favorite constellation: it's the smallest of the 88, but on average has the brightest stars (featuring 3 of the top 25). Two even brighter stars (3rd and 11th), Alpha and Beta Centauri, point at the Southern Cross (and are hence called "the Pointers"), and these 6 stars can be used to find due south (see figure above). Four of the six stars are blue-white, one is orange, and Alpha Centauri is a beautiful golden yellow (actually two sun-like stars). The six stars include the first two binary star systems detected, and the first star (Alpha Centauri, the closest star system to us) to have its distance from us measured. The Southern Cross lies in the plane of our Milky Way galaxy, which is considerably more prominent in the southern hemisphere sky as it looks toward the dense galactic center rather than the sparser outer regions of the galaxy as in the northern hemisphere. Some other interesting objects in the vicinity of Crux include the massive shadowy Coalsack Nebula and the Jewel Box cluster.

I love astronomically-inspired chandeliers, having made two based on the solar analemma. I was born and grew up in NZ, and the constellation is part of the flag, as it is for Brazil, Samoa, Australia, and Papua New Guinea, so the Southern Cross was a natural inspiration for a new one. While doodling a shape to base the frame on, I drew a breaking wave form through all six stars. It had the happy result of generating a stylized koru (the shape of a growing fern frond, and a staple feature of Maori art) in the negative space. Not everyone has been immediately reminded of these shapes though - I've had everything from a dragon's tongue to a shepherd's crook to a question mark! But that's OK - I like the fact it starts a conversation, and given that I'm in Canada, it is perhaps unsurprising people are not reminded of a constellation that most have never seen or a shape that doesn't culturally resonate.

To make it more astronomically authentic, the lights can be programmed to mimic the color and relative brightness of the individual stars (I have a scene in the Wiz app called "Crux"). It also has a disco mode, which is fun for parties!

Supplies

Tools: laser cutter, cordless drill, trim router, orbital sander.

Supplies: 3 mm (1/8") plywood, construction adhesive, formica laminate, wood filler, spray paint, light sockets, cables for hanging, pendant light cover, light bulbs.

Note: links above are affiliate links, from which I receive a small commission from sales (it does not cost you anything extra). The links are to the actual tools/materials I used; if things are missing links I probably got them locally.

Step 1: Design

All design was done in Fusion360's sketch mode. The stars were first placed in their correct relative positions using a canvas. I mostly used arcs and spline curves and there was a lot of trial and error involved in getting the shape of the wave/koru as pleasing to my eye as possible while keeping the stars centered on the complex curve.

To make the chandelier fit on the laser cutter, I made jigsaw-like cuts offset on each layer. The size of the chandelier isn't critical and there is no reason it couldn't be bigger or smaller. However it cannot be scaled without also adjusting the sizes of the finger joints and the circular cutouts for the lights.

The Fusion360 file is freely available at https://a360.co/3S3EOZE and an stl is attached so you can view the design in 3D if interested.

SC.stl
Download View in 3D

Step 2: Laser Cut

I used a Speedy360 laser cutter to cut the shapes out of 3 mm plywood. The cutting files are attached as .ai and .eps.

Step 3: Assemble

Glue the two layers that make the bottom of the chandelier together on a flat surface, using weights as clamps. Do the same with the top layer, making very sure that the smaller layers are facing each other and that the bottom layer is facing in the correct direction (you don't want the mirror image!). Use the holes in the plywood as alignment aids to get everything lined up perfectly. Note the inside layers are slightly smaller than the outside; you'll see why in the next step. Once dry, bolt the lamp bases into position in the top layer (hole positions have been laser cut). You will have to cut two of the bases to fit - it's easy to do because they're plastic, any saw will do. The one second from the tip needs about 1/4" (6 mm) trimmed from each side, the one at the tip needs about 1" (25 mm). Be sure to avoid trimming off the mounting holes!

The large holes accommodate the bulbs on one side, and allow access to the wiring on the other.

Now glue the finger jointed bridging pieces into the bottom layer and then into the top layer. Ensure the vertical pieces are exactly vertical by clamping the end piece against a block of wood (that precaution will draw all of the other pieces vertical). Clamp using weights and leave to dry.

Step 4: Wire

Wire the sockets together in parallel. To do this, run a wire to each of the connectors on each socket. Bring those wires to a central point, then ponytail the wires together (all the gold ones together, all the silver ones together). Add an extra wire to each to allow connection to power. I decided to do some cable management and drilled holes in the top layer to route the cables inside the chandelier and to use zip ties to fix the cables at the top.

I arranged for the power to be sourced from roughly in the middle. I used some leftover cabling from another project. Test it before you close in the sides!

Step 5: Edge Pieces

Cut strips of laminate 98 mm wide. Any colour is fine; the whole chandelier will be painted. Cut them to the lengths of each side (it is easiest if you do the two long pieces first and cut slightly long). Glue in place using construction adhesive and plenty of clamps and duct tape. Note how the laminate fits in the rabbet created by the differentially sized layers. Wipe off any excess glue on the outside. Trim the end using the palm router and add the end piece; trim all edges with the palm router and tidy up using a file and/or sandpaper.

If you are having difficulty bending the laminate for the tightest part of the curve, get a heat gun and bend the laminate around a large can first while heating gently. Hot laminate bends easily. If you don't have a heat gun, try sanding the back of the laminate to make it thinner and more flexible.

I made the mistake of making a join in a sharply curved region. I had to do a fair bit of clamping and filling and sanding , which was time-consuming and tricky. In hindsight, I would have made the join at one of the finger-jointed cross-pieces where the curvature was near-zero.

Step 6: Fill and Sand

Get some wood filler or Bondo or similar. Fill in all the cracks and cover the face of the plywood as well (especially the jigsaw joins). Sand. Repeat until the surface quality is to your liking. Plywood's grain tends to pop out with painting so covering the whole surface with a thin coat of filler is a good idea.

Step 7: Paint

Stuff a ball of paper inside each socket to prevent overspray. Spray paint the chandelier in whatever color you like. I chose black. Many thin coats with very light & fine sanding between coats will get you the best finish. I didn't bother to do the top at all, as it is not visible from below.

Step 8: Hang

I used 3 adjustable cables. I found it to be easiest to do this with help, the chandelier is not heavy but it is awkward and you will soon run out of hands if doing it by yourself. String it up using cord, get the whole thing positioned to your liking and leveled, then replace the cord one at a time with the cables. Tweak the level once securely in place. Wire the chandelier to power.

Because the chandelier is a torsion box, it is not prone to warping so don't worry too much about exactly where the cables are - I just placed them as far apart as possible.

Step 9: Add Lights and Program

I used 6 programmable LED lightbulbs so I could select the colors to match the stars. If you don't feel you need this level of nerdy detail, just use regular bulbs. I set each one up to represent the relative brightness and color of each star. Set this as a "scene" so you can return to more conventional lighting if you like (or even party mode!). The chandelier is very bright on maximum setting - each of the 6 LED bulbs is a 60W equivalent.

And yes, I do have two astronomically-inspired chandeliers in the same room. I'm already planning a new one for the kitchen!

In the (in fairness, wildly unlikely) event you reproduce this project, please post a picture! I'd love to see it.