Mini Sun Funnel Idea
A sunny day on the heels of the 2015 GLPA Conference in Grand Rapids, MI, was cause to bring out the telescope and test some Sun Funnel ideas.
After testing the prototype Sun Funnel, I tried some alternative designs. For example, I made a mini Sun Funnel by inserting an eyepiece into a paper towel tube and capping it with a small sample of wound cardboard holder with rear projection screen.
Because the tube diameter is so small, only a fraction of the sun's surface area fits within the projection. In the image above, a pair of sunspots are visible just within the bright limb of the sun.
Meanwhile, other people have suggested using a shower curtain instead of the more expensive rear projection screen. I affixed a toilet paper tube with shower curtain material snugly to an existing eyepiece. You can even see the circular magnet in the corner.
Again, you can see two sunspots just within the curved limb of the bright sun. Only a fraction of the projected sun fits across the tube.
More experiments to follow.