The arc here is about 1.5". Next up I'll make a ball gap and add some capacitors. Stay tuned...
|Smell the ozone|
|So far so good...|
I found a fast way to mark and cut the 36 aluminum tape strips used for the "rods". I had a scrap piece of 1/4 inch thick aluminum plate, with a straight base about 4 inches long. Setting the base cross-wise on the aluminum tape, I marked the 1/4 inch width, Then I flipped the plate on its side, and used the long edge as a guide for cutting the tape at the marks with a hobby knife.
|Don't look too closely|
|Click to enlarge this mistake|
|Doing it right the second time|
"Ulexite is also known as TV rock due to its unusual optical characteristics. The fibers of ulexite act as optical fibers, transmitting light along their lengths by internal reflection. When a piece of ulexite is cut with flat polished faces perpendicular to the orientation of the fibers, a good-quality specimen will display an image of whatever surface is adjacent to its other side"In other words the image appears to be on the upper surface, not under the rock the way it would under a piece of glass:
"...if unpolarized light enters the material at a nonzero acute angle to the optical axis, the component with polarization perpendicular to this axis will be refracted as per the standard law of refraction, while the complementary polarization component will refract at a nonstandard angle determined by the angle of entry and the difference between the indices of refraction, known as the birefringence magnitude. The light will therefore split into two linearly polarized beams, correspondingly known as ordinary and extraordinary."In other words, light of a one polarity will pass the crystal at one index of refraction while light polarized at the complementary angle (∆ 90° or 270°) will be refracted at a different index. The result is two separate images. The relative position of the secondary image to the primary image changes as the crystal is rotated.