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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! So I decided to make an LED chandelier with 365 LEDs, which mimicked the solar analemma and therefore acted as both a stylistic astronomical calendar and a source of illumination for our dining room. I decided to stretch the analemma in such a way that it could be cut out of a 4' × 8' piece of plywood and the LEDs could be placed accurately. This last requirement was really important to me... and made the project vastly more challenging, because every. single. last. LED. needed to be uniquely located and was uniquely spaced.

* this is a famously hard photographic challenge - the first example was recorded by Dennis di Cicco in 1978-9. Check out some of the others. My favorite has to be Tunc Tezel's "Tutulemma": an analemma photograph that includes a total solar eclipse!

Step 1: 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. I used his spreadsheet to calculate the solar analemma for the exact latitude and longitude of my house for the calendar year 2016, did some manipulation to convert it into the right aspect ratio to fit it comfortably on to a 4' × 8' sheet of plywood, and imported it into Fusion360 using Add-Ins > Scripts > ImportSplineCSV. That created all the points I needed. I created offset lines 50 mm out from this line on both sides, and extruded the resulting shape 18 mm (I planned to cut it out of 3/4" plywood). I then bored 364 holes (yes, 364; two of the holes at the "X" of the figure 8 almost overlapped, so I averaged their position and just made one hole there) 8 mm in diameter all the way through the material. Another 364 holes 14 mm in diameter were bored in the same position but only 15 mm deep.

<p>Absolutely beautiful. Even better, it might be the fussiest project I've ever seen! Well done, sir.</p>
<p>Thanks. Certainly the fussiest I've ever done! Was worth it though</p>
<p>I am a novice when it comes to Programing, but it is easy to tell Mike wrote a beautiful code. Thank you for sharing your chandelier, it is epic! </p>
<p>Agreed! He did an amazing job. And thanks</p>
<p>The link to the LEDs on Amazon does not work. Does anyone know which LEDs these are?</p>
<p><a href="http://amzn.to/2h2ELye">Link fixed</a>. Thanks for the heads-up.</p>
<p>Sorry to harp on this, but Im still not getting the link to work for the LEDs. Amazon showing &quot;no page here&quot;</p>
<p>Sorry! Thanks for letting me know. Try <a href="http://amzn.to/2gKQU7v">this link</a>.</p>
<p>Where can one get the spreadsheet to calculate the analemma?</p>
Contact Larry McNish (see step 1). He is very generous, but I am unwilling to pass on his hard work myself.
<p>WannaDuino!!! Likes iT!!!</p><p>Amazing dear friend,</p><p>You are also an amazingly good photographer, can you maybe explain the picture how to make, Where you are 4x in the frame? so 4 pictures become 1?</p><p>WannaDuino!!! </p>
<p>No, it's just a movie taken with my phone that I sped up to 4x (four times) speed using iMovie. Otherwise I doubt people would be patient enough to watch the whole thing.</p>
<p>This is brilliant! I've wanted to do my own analemma photos over a year where I live -- but sadly my inspiration in this case runs far ahead of my abilities! THIS, however, I may be able to translate into something I CAN do. Thank you so much! </p>
<p>Thanks. Good luck with the build, if you do take it on.</p>
<p>My expertise is more with fiber arts (the hoity-toity name for sewing and needlework) -- and what comes to mind has to do with fabric on a stretcher -- eventually to be hung from (on?) a ceiling . . . . but given that I'm about to purchase a new house, it seems, it seems unlikely I'll get to anything that creative any time soon. Thanks esp. for the post of the analemma with solar eclipse. // Question: do you happen to know if anyone has ever compared the analemma with the shape of the Mobius strip? I know, nothing to do with each other, but it doesn't hurt to ask . . . . </p>
What will you do to hide the massive power supply in your dining room? It's a great project.
<p>Good question! It is a beast. I need to make something to hang the fitting from in my dining room, and I will make room in that for the power supply.</p>
I have concrete ceilings so likely not possible. I'm assuming this transformer can be hard wired to a switch?
<p>I'm not going to cut into my ceiling either - they're solid wood. It will be more of a ceiling-mounted box. But yes, the transformer can be wired directly into the home supply like any light fitting.</p>
<p>Excellent project! I really like how you can switch between the different modes of lighting. I might try adapting your code for a LED project I've been working on. </p>
<p>Thanks Jeff. Thinking of a party mode for <a href="https://www.instructables.com/id/Cielo/">Cielo</a>?</p>
<p>its cool.. think to use hacksaw and drill since i dont have a machine..</p><p>look mine to <a href="https://www.instructables.com/id/Lumen-Histoire-IoT-App/">https://www.instructables.com/id/Lumen-Histoire-IoT-App/</a></p>
<p>I bet you'll win at least 2nd place in the Make It Glow contest.</p>
Really, Really Cool. I have always been fascinated by the solar analemma phenomenon and you've captured it really well. Good job :)
<p>Thanks! </p>
<p>This is awesome! I love it :) I'd love to see it as a chaser light that gets brighter and stays on longer between lights during the summer section and gets dimmer and shorter during the winter part.</p>
<p>Thanks. The great thing about having addressable LEDs is that you can reprogram them to do whatever you want. Your idea sounds cool. </p>

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Bio: Analog maker dabbling in digital manufacture
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