6 inch diameter solar viewer

thingiverse

I have been working on designs for solar viewers for the April 8, 2024 total solar eclipse and initially came up with this one: https://www.thingiverse.com/thing:6243278 then I improved on this to make it less expensive and easier to assemble: https://www.thingiverse.com/thing:6306688.Since designing these, I have made larger ones using a 10 - 30 x 50 zoom monocular I found at Amazon for a good price. I later found a similar one even cheaper - less than $20 when I ordered it and the quality seems very good for the price.https://www.amazon.com/gp/product/B0CDPV3F4C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1A tube would make this heavy so I designed an open design, initially using carbon fiber arrow shafts and designed and 3D printed a central support truss and end caps. This was at about the limit of my printer and thus 8" in diameter but the truss alone took over 20 hours to print and used almost 1/3 of a spool of filament (Cura estimated 325 g). It took over 40 hours to print all of the parts and this was at 200 mm/s.Then the arrow shafts would not fit through the truss even though I designed the holes oversized. I tried drilling these out and tried different size drills and ended up with a 12" long 21/64" drill but it overheated going through the long holes and melted the PLA which ended up twisting and cooling onto the drill. This took a while to try and save the truss and drill. I was able to finish this 8" version but there were enough issues that I did not try and clean up the design.I had seen that someone had designed a 6.3" Newtonian telescope using threaded rods so I came up with a much easier to build 6" diameter viewer that used less filament and printed much faster. My first design was based on 1/4 - 20 threaded rods but that was heavy so I redesigned it to use #10 - 24 x 24" threaded rod from Home Depot:https://www.homedepot.com/p/Everbilt-10-24-in-x-24-in-Zinc-Threaded-Rod-802137/204274010Plus 12 10-24 nuts and 6 10-24 acorn cap nuts for a finished look.Being larger and heavier, I looked for a more robust way to add the 1/4 - 20 tripod mount and found these rivet nuts with a flange which would prevent them from pulling out. I did not rivet the nut in, my prints have turned out accurate enough the nut just taps in with a hammer and stays in place but you may have to open up the hole a little if it is too tight or glue it in if it is to loose.https://www.amazon.com/gp/product/B0BVF8Z3HD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1For the position of the truss, I would normally adjust it to have the center of mass over the tripod mount but, because the center of mass is so far above the mount, I set it up so the center of mass is above the mount when the viewer is at about a 45 degree angle.You can adjust the nuts on the truss to get all of the rods aligned or adjust the tripod mount.Since the top and bottom plates might not be perfectly aligned along with the monocular's axis, there may be some direct sunlight on the viewing plate. I designed a larger diameter sun shield to correct this and made it out of TPU to provide some shock absorbing in case the viewer tips over. I have had this happen because it is top heavy.I also designed an optional extension lever for the zoom ring on the monocular. This uses M3 screws.To hold the monocular to the top plate I used a nylon 1/4 - 20 thumb screw but had to cut it down to work.https://www.amazon.com/dp/B0BXHV4TBR/ref=twister_B0BXHTMPM7?_encoding=UTF8&th=1The 2 close-up photos show the size of the image at 10X and 30X.I have included a "family portrait" of most of my recent solar viewers I have designed.