Solar Analemma Chandelier 2.0

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Introduction: Solar Analemma Chandelier 2.0

About: Analog maker dabbling in digital manufacture

Some years ago I built a solar analemma chandelier, using 364 addressable LEDs as the source of the light. It was a lot of fun and a real talking piece, but as a practical dining room light, it was far from ideal - it was not quite bright enough nor was the quality of the light especially good (to get a nice warm light you have to set it to almost yellow). So I have built a brand new one using 51 LED bulbs instead, one for each week of the year (the bulb at the crossover point serving two dates, hence 51 not 52 bulbs). Each bulb is the equivalent of a 40 W incandescent bulb, so it provides masses of (dimmable) light. It doesn't quite have the wow factor of the programmable LED analemma, but it is much more practical and still looks beautiful.

The solar analemma is the shape described by the sun when photographed over the course of a year at the exact same time of day and same location.* Because the Earth's axis is tilted and its orbit is elliptical rather than circular, it generates an asymmetrical figure of eight. And a beautiful one! This one mimics what the sun would look like if I took a photo at 12 pm every Tuesday of the year from my house.

* this is a famously hard photographic challenge - the first example was recorded by Dennis di Cicco in 1978-9 (3rd photo above). My favorite has to be Tunc Tezel's "Tutulemma": an analemma photograph that includes a total solar eclipse! (4th photo above). More info on the solar analemma available here.

Supplies

You will need either a 4' × 8' CNC machine OR a laser cutter, a jigsaw, and a router with a flush-cutting bit. When I made the last one, I had access to a ShopBot while I was an artist in residence at Autodesk's Pier 9 workshop. But I no longer have this access, so I adapted the design to a laser cutter. You will also need some plywood (1/2" and 1/4"), some formica laminate or edge-banding, wood glue, and whatever stain/paint finish you want for the chandelier. You'll also need some cables to hang the chandelier and 4 strings of 15 bulbs. And some replacement bulbs.

Step 1: Design and Laser Cut

I already had a design (Earth's orbit took care of all the pesky details of creating the beautiful shape, and Larry McNish of the Calgary Centre of the Royal Astronomical Society of Canada did all the hard work of creating the spreadsheet that computes the layout) for the analemma, stretched so that it filled a 4' × 8' sheet of plywood. Happily, this stretching has the effect of separating all of the points to a reasonable distance in all directions. I adapted it for 51 bulbs and so it could be cut out on a laser cutter. The idea was to break up the big design into pieces small enough to be cut on the laser, then the pieces would be used to generate a template that locked together like jigsaw pieces. But what made this idea work really well is that the template becomes part of the build! The Speedy360 I used had a bed size of 500 × 800 mm, but the longest pieces are less than 500 mm so most laser cutters ought to be able to handle them. The files are attached to this step in .dxf format. Cut them out of 1/4" (6 mm) plywood (I used 3 mm plywood, but in hindsight that was a mistake - see next step).

Step 2: Glue and Cut

Lay the template pieces out on your sheet of 1/2" (12 mm) plywood using the picture from Step 1 as a guide, and glue them down with wood glue, holding them in position using weights. Make sure you thoroughly clean up any glue that oozes out. Once dry, cut out around the template using the jigsaw, leaving whatever margin that you feel you can safely cut to (a few mm = 1/8" should be fine).

Note: I used 1/8" and 5/8" plywood, but found the bulbs wouldn't quite screw in properly. I only found they didn't fit after finishing the build and hanging it up - I had to remove it, drill out deeper holes, refit the lighting harness and rehang. Yikes. If you use 1/4" plywood for the template, the holes will be the perfect depth.

Step 3: Trim

The magic happens with the flush-cutting bit - clean up the nasty jigsaw cut with the router to leave a beautifully finished figure-of-eight. Your 1/2" (12 mm) plywood is now 3/4" (18 mm), and the template has become part of the build itself, which is really satisfying. Tidy up the internal corners of the figure-of-eight using a sharp chisel.

Step 4: Drill

The lights have a collar that is accommodated by the laser-cut holes in the template. You need to cut slightly smaller holes in the 1/2" plywood. Use the circles you cut out with a central hole pre-cut to drill small holes to get the centers perfect, then from the other face drill 1 3/8" (35 mm) holes in the plywood using a Forstner bit.

Step 5: Edgebanding

With my original analemma chandelier I used maple edge-banding, but this time I wanted a black frame so wasn't worried about matching the materials, so I used some strips of laminate left over from building my kitchen counters. This worked really well - the laminate is plenty flexible enough but much stronger and stiffer than the edge-banding, and it didn't need any additional support (except for the crossover part, which I strengthened with some blocks, see photo). I glued it on the edge with construction adhesive and lots of clamps. I tidied it up with a flush-cutting bit in my laminate trimmer (a one-handed router). Some wood filler to fill scratches and seams, plenty of sanding and it was ready for painting.

Step 6: Add Finish

I spray painted the chandelier with lots of light coats of black gloss paint.

Step 7: Lights

I bought 4 sets of string lights, and chopped them up to get a more compact harness. Each join was twisted, soldered, and covered with heat-shrink tubing. This was pretty time consuming and I can't imagine doing it without some decent wire strippers. Pop a socket in each hole and screw the T-junction to the chandelier using the holes provided (I used 1/2" screws and some small washers). The sockets should fit fairly firmly in the holes but even if they're a bit loose, don't worry - the bulbs will hold them in position.

Step 8: Hang

Suspend the chandelier using wire cable at several points. I used 6 hanging points and eye screws in both the ceiling and the frame. It is a hassle to get it level - I strongly suggest getting help! Tie it up at 3-4 points using cord and some helpers, use a spirit level or laser level to get it hanging perfectly, then add the adjustable wire cables. This kit has all the parts you need.

Wire the harness to your ceiling fixture (I used a pendant light cover) using pony tails. Add the LED light bulbs. If you don't already have a suitable dimmer, get one! You'll need it, 51 lights is WAY too bright for most dining room settings unless you're planning an interrogation or a photo shoot.

Enjoy your new light fitting, and make sure your guests appreciate the astronomical significance of that interestingly asymmetric figure-of-eight.

Step 9: On Reflection

One of the neatest things about this chandelier is that it creates beautiful reflections everywhere in the room. On paintings, plates, wine glasses, eyes, you name it! All very cosmic.

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    23 Comments

    0
    NerdSnipe
    NerdSnipe

    20 days ago

    I absolutely love this! I do feel like it might need a disclaimer about the load that it pulls. Most American houses seem to be wired for 15 amps. If running full steam at 40 watts with 51 bulbs this is pulling over 18 amps. This will trip breakers for many people (though with that many bulbs you probably don’t ever need it that high). If you want to make this you’ll probably need a dedicated 20 amp breaker with the appropriate usage of wire just for this one light fixture. You’ll probably be breaking code too, which limits the number of lights on any breaker. Also… the heat… soooo hot! Be smart and don’t use energy wasting incandescents. Use the LEDs for sure.

    0
    makendo
    makendo

    Reply 20 days ago

    Yeah, it uses 40W *equivalent* LED bulbs, so it’s only actually drawing 4W per bulb, total 204W. And it is hardly ever above 30% brightness

    0
    KevinKarney
    KevinKarney

    21 days ago on Step 9

    Great Idea! I love it. I am writing a book about the Equation of Time and the analemma. With your permission, I would love to include an image from your submission.If anyone else builds this, It would be great to use coloured LEDs and change the colour of the LED nearest the date. Another much more difficult challenge is to place a tiny mirror on a south-facing window ledge and, when the sun shines, mark the reflected spot on the ceiling at (e.g) noon. Over the year(s), you can plot the analemma and thus create a noon dial. I know of three examples where this has been done - (not by me!)

    1
    makendo
    makendo

    Reply 21 days ago

    Sure, you are welcome to include any image with the appropriate attribution. Check out v1.0 of this analemma at https://www.instructables.com/Solar-Analemma-Chandelier/, it was done with 364 addressable LEDs and lights up like a sunrise starting at the day of the year you're in. I like the mirror idea, very cool - alas I have no unshaded south-facing windows!

    1
    Netguy
    Netguy

    23 days ago

    Looks fantastic. Why 51 and not 52 weeks?

    0
    makendo
    makendo

    Reply 22 days ago

    Great question! The crossover point just uses 1 bulb even though the sun is in that one position twice per year.

    0
    Netguy
    Netguy

    Reply 21 days ago

    Ahhh. Makes sense. I thought that might be the case. Thank you.

    0
    AnneGast
    AnneGast

    Reply 22 days ago

    I was wondering the same thing.

    0
    SeanMakes
    SeanMakes

    22 days ago

    Beautiful job! I like your previous one as well!

    0
    makendo
    makendo

    Reply 22 days ago

    Thanks, me too… v1.0 is hanging on my office wall now

    0
    snorlaxprime
    snorlaxprime

    22 days ago

    Great work, love to see the infinity shaped of the solar analemma shape

    0
    edabney
    edabney

    22 days ago

    Hey, I was revisiting many of your earlier projects and noticed that most of the videos are no longer available. Are they available on a different channel or a different platform now? Thanks

    0
    makendo
    makendo

    Reply 22 days ago

    Ugh. Probably a change in how YouTube and/or Instructables allows links - a lot of them I set up to autoplay (no sound!) so they looked like an embedded gif. Thanks for letting me know, I'll go see if I can fix them...

    0
    makendo
    makendo

    Reply 22 days ago

    Yeah, it seems YouTube videos can no longer be embedded in steps. I've updated the original solar analemma chandelier instructable with the right YouTube links. Thanks again!

    0
    OneBirdieMa
    OneBirdieMa

    23 days ago

    Magnificent!

    0
    makendo
    makendo

    Reply 23 days ago

    Thanks!

    0
    Donald Bell
    Donald Bell

    24 days ago

    Outstanding! I love the way this looks. Modifying the lights seems like a chore, but worth it for the end result.

    0
    makendo
    makendo

    Reply 24 days ago

    Thanks Donald! Yes, I did it in 3 stints of about an hour each. The wirestrippers gave me a friction blister in the first stint. I thought initially I'd just do some cable management but the cables were longer and heavier than I'd imagined, so I didn't want that extra weight overhead. Do you remember the original addressable one?

    0
    Donald Bell
    Donald Bell

    Reply 24 days ago

    Absolutely! Vividly. Along with your laser vape lightsaber, warping infinity mirror, periodic table lamp, laser cut contour map... classics, all of them.