Solar Filter Holder for Binoculars

thingiverse

I've been preparing to capture and photograph the upcoming US total solar eclipse. This is a simple ring design for securing solar filter film onto a pair of binoculars. It was engineered specifically for Bushnell 10x32 binoculars, which have a 42mm diameter at the front lens tube, but can be adapted for other models by scaling up or down in both dimensions to accommodate differing diameters. Print two copies on your 3D printer, with them facing downwards as shown. To assemble this design, carefully cut a piece of certified solar filter film large enough to completely cover the front lens element. Place it atop the lens tube, then slide the retaining ring onto it to secure it in place. On my print, it provides a decent friction fit, but if the binoculars are going to be handled frequently and you want extra assurance that the filter stays on, wrap some gaffers tape around the joint for added security.