Embiggen Your Eclipse 2017 Experience With A Sun Funnel

As exciting as Eclipse 2017 is going to be this Monday, for some folks it might appear a bit — underwhelming. Our star only occupies about half a degree of the sky, and looking at the partial phase with eclipse glasses might leave you yearning for a bigger image. If that’s you, you’ll need to build a sun funnel for super-sized eclipse fun.

[Grady] at Practical Engineering is not going to be lucky enough to be within the path of totality, but he is going to be watching the eclipse with a bunch of school kids. Rather than just outfitting his telescope with a filter and having the kids queue up for a quick peek, he built what amounts to a projection screen for the telescope’s eyepiece. It’s just a long funnel, and while [Grady] chose aluminum and rivets, almost any light, stiff material will do. He provides a formula for figuring out how long the funnel needs to be for your scope, along with plans for laying out the funnel. We have to take exception with his choice of screen material — it seems like the texture of the translucent shower curtain might interfere with the image a bit. But still, the results look pretty good in the video below.

Eclipse 2017 is almost here! How are you planning to enjoy this celestial alignment? By proving Einstein right? By studying radio propagation changes? Or just by wearing a box on your head? Sound off in the comments.


7 thoughts on “Embiggen Your Eclipse 2017 Experience With A Sun Funnel

  1. Don’t use your favorite eyepiece. If your scope is too big, it will overheat. Best to use a small scope ~4 inch size is best and a “junk” glass eyepiece to do the projecting. I bought a less than perfect Edmond Scientific Astroscan unit that is so friendly that I take it out for almost all solar events. My dog and I used it to watch a partial solar eclipse a few years ago. Short video shows what I mean. :-)

    1. This. Test runs with my Celestron 70mm made some magic smoke in the eyepiece. I used a paper-punch and aluminum foil to shield the lens mount, plus used the smaller port in the primary lens cap and may cover that with mylar to decrease the input — we’ll see. At the very worst I’ll be back to pinhole projection and out a cheap eyepiece.

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