Low Cost Solar Viewer

thingiverse

This is an updated version of my Solar Projector https://www.thingiverse.com/thing:6243278 but designed to be lower in cost and requires no cutting of plastic like the original. Once the 3D parts are printed, this viewer can be assembled in very little time.It would make a good STEAM project for schools and other organizations.It uses a 4" x 24" cardboard mailing tube. The 4" was chosen to provide a larger viewing area and so it doesn't have to be re-positioned as often.The tube can be used as-is or personalized by painting, using decals or wrapped with decorative paper.This design is based on Tasco's newer 10 x 25 monocular as it appears the older one I used in the previous design may have been discontinued. I ordered one from Amazon for about $16. https://www.amazon.com/TASCO-568125-Essentials-Monocular-Black/dp/B01EC4VO0E/ref=sr_1_1?crid=9EURMFN3GT5D&keywords=tasco+10x25+monocular&qid=1699570518&sprefix=tasco+10x25+monocular%2Caps%2C503&sr=8-1The 4" x 24" mailing tubes are available at various locations but I ordered a pack of 12 for $4 each from Walmart. https://www.walmart.com/ip/Tubeequeen-Kraft-Mailing-Tubes-with-End-Caps-Art-Shipping-Tubes-4-inch-x-24-inch-Usable-Length-12-Pack/976748432?from=/searchAs with the previous design, the wrist strap mount on the monocular needs to be removed so it will slide in the 3D printed mount and this is done by simply unscrewing the mount. I cut out a circular piece of paper for the viewing screen and attached it with a small piece of double stick tape in the center so it can be removed and replaced if necessary.The only other items required beside the monocular and mailing tube are a 1/4-20 nut for the tripod mount and some zip ties to hold the tripod mount to the tube.You can glue the 3D printed mount and viewing cap to the tube or just use tape such as electrical tape that I used.The monocular is inserted eyepiece down into the viewer and the mount is designed to only hold onto the eyepiece portion so that it can be focused by rotating the end of the monocular that extends out of the mount.The monocular is only held in by friction so it might fall out if the viewer is held upside down so it may be best to remove it when transporting the viewer. Update:I created a small shield ring that can be placed over the monocular to provide some extra blockage of stray light from getting around the monocular but it may not be necessary. It will be tight and may need to be sanded around the inside of the ring to open it up to fit.SAFETY NOTICE:Never look at the sun directly through the monocular.Update:I found that the smaller Tasco monocular is their newer version but Walmart may still sell the larger version so I created a version of my 4" mailing tube mount for the larger Tasco monocular which comes in a blister pack whereas the newer, thinner one comes in a box.I also added a corresponding larger lens cap that includes a loop to tie a string to the loop on the mount.With the larger Tasco monocular, there has to be a larger gap between the opening and the monocular due to the extra diameter of the grip so I created a split grommet to fill in this area after the monocular is almost fully inserted but it may not be necessary.I accidentally tipped over one of these viewers and broke the tripod mount at the 1/4-20 nut. I had to make that area thin (about 0.05") so the nut sits low enough to get enough threads from the tripod but it was rather thin so I updated a version which is a little thicker (about 0.075")Update:While I like the larger viewing area of the 4" viewer, it does seem a bit bulky so I created a mount and viewing cap for a 3" x 24" mailing tube. These tubes are cheaper and may be more readily available. Staples.com shows that they may be available in their stores. I ordered a pack of 12 from Walmart for less than $3 per tube and these are the white rather than natural cardboard tubes.Update:I was asked if the viewing plate was removed, could the Sun's image be projected on the ground which might make it easier for more people to see the image.I tried this but the image can get too dim to see clearly so I took this as a challenge to come up with a new design that might be better for larger groups.What I came up with is a larger diameter one using a larger and more expensive monocular and a new overall design which still needs some refinement but the success so far has lead to improved viewing caps for both the 3" and 4" versions and maintains their low cost.My newest viewing caps also print faster and use less filament while providing a wider area from which the image can be seen.I use Cura's tree support, only touching the baseplate for these.