Kaleidoscope Fun

Reflections

From time to time, just for fun, I've made a number of kaleidoscopes and holoscopes, mostly from cut-and-stick auto replacement mirrors. These auto mirrors are less expensive than front-surface glass mirrors, and they can be cut with ordinary scissors rather than requiring glass cutting tools and expertise.

My kaleidoscopes are rather ugly when compared with exquisite models made by artistic experts. Mine have no exterior decoration and are held together with masking tape and duct tape. Nevertheless, they produce some nice complicated views. Four of my constructions are shown in the first picture below. From left to right they are: a tetrahedral holoscope, a narrow kaleidoscope with three mirrors, a cubical holoscope, and a three-mirror kaleidoscope which produces a spherical image.

First, consider the cubical holoscope. Five identical small square glass mirrors are taped together with an equal size auto replacement mirror closing the cube on top. Reflecting surfaces all face inward. As you can see in the next picture, I cut away the corners of the top mirror. Three of the missing corners are covered with different colors of transparent plastic. The remaining open corner in the upper left is a viewing hole.

Light entering the cube through the open corners undergoes multiple reflections producing repeated images. Looking through the viewing hole while shining light down on the cube from above produces the following scene.

If I gently press on the slightly flexible top, some lines of multiply reflected images bend.

The tetrahedral holoscope is a 4-sided tetrahedral volume whose sides are equilateral triangles. Each internal surface is a mirror. I cut holes in all four vertices, making the "top" vertex viewing hole the largest. I covered the remaining three holes with red, green, and blue transparent plastic respectively. The next two images are views into the tetrahedral holoscope when it is illuminated by an overhead light along with three additional separate lights pointed at the color-covered vertices.

It looks like the openings with colored plastic should have been bigger because all the colored reflections seem small.

The narrow triangular kaleidoscope produced surprisingly interesting patterns when illuminated from the viewing direction. The next four images were generated by looking at breakfast cereal boxes through the kaleidoscope. Different cereal boxes and slightly different camera tilts produced different patterns.

The last of the four kaleidoscopes produces an amazing spherical pattern. The three sides of the device are cut to specific angles to achieve this effect. The light source is from the same direction as the viewing direction.

Someday I hope to find a way to illuminate the kaleidoscopes from the bottom instead of from the top.

Sunspot Surprise

Flaring Spot

During recent months while the Sun approached sunspot cycle minimum I've observed a disappointing lack of dramatic solar features. Just in time for August's solar eclipse, however, two significant sunspots appeared and provided nice background markers for that event. Then, two weeks later, more sunspots blossomed, including two major groups nicely placed near center on the solar disc. What a pleasant surprise! All requirements for good observing lined up on September 4th: clear sky, no wind, temperature in the 70's, and good seeing.

Features were distributed across the entire Sun, so it was worthwhile to attempt a panorama capturing the whole scene. The following image is a 48-panel mosaic showing lots of action. Good seeing conditions prevailed throughout capture of 48 video clips, so this is one of the most detailed mosaics I've been able to construct. Sunspot group 2674 is nearly centered on the disc. Sunspot group 2673, threaded with white energetic emissions, is located to the lower right of center. Some smaller white active regions and a few filaments are scattered about. Two significant prominences are visible, including an enormous one at lower left. (Click on any image below for larger views.)

The next 9-panel mosaic shows an enlarged view of the two major sunspots along with a hook-shaped filament.

Next is an individual close view of sunspot group 2674 with multiple umbras stretched horizontally across the image.

The following enlarged view of sunspot group 2673 shows detail in the energetic white emissions threading through the group.

The white threads were continually changing as I watched for more than two hours. They brightened quickly from time to time when minor flares burst forth saturating the camera as you can see in the image below.

Two days after my observations this area emitted two X-class solar flares, the most powerful type of flare. The second flare was the most powerful to appear in eleven years! Auroras appeared as far south as Virginia and North Carolina, but they were truly spectacular in Norway!

The final image shows a close view of the large, curtain-like prominence hanging above the solar limb.

Since sunspot 2673 was changing rapidly, I decided to record a time lapse video of the action. For two hours, from 10:20 to 12:21 EDT, I recorded one video clip per minute. I hope to eventually assemble the 122 still images into a movie of the flaring activity I saw.