Fresnel Lens

UPDATE - - 06 NOV:

Another version for your consideration. The original one was segmented and based on spherical geometry. This one is a single piece and based on parabolic geometry. This makes a better image from parallel rays, such as come from the sun. You can see from the pictures that the focus/intensity is significantly better.

This is a little smaller than the fully assembled previous one. This is as big as will fit in my tank all at once. Using the segments, I can make pieces at least twice the size of what I already did.

PS - The stripes near the bottom are very minor irregularities from the printing process. Due to the angle of the sun, they look overly dramatic. Not to worry.


ORIGINAL - - OCT 28:

A segmented Fresnel (Frah-NEL) Lens. It has a focal length of about 7 inches.

Now I am just a few bricks, a kerosene lamp, and a rock island short of a lighthouse.

https://en.wikipedia.org/wiki/Fresnel_lens

Due to the smallish build volume of my printer, t