Parry 1820 - explanation

3D Model

The display of 1820 was made by crystals of different shapes and orientations. Here I consider only light effects given by Parry crystals. Parry oriented crystals are columns laying flat as though they were put on a table. Such a situation is very rare. Their length can vary. I have chosen regular columns twice longer than broad.

At first you see the original view. Then the part given by Parry cystals is more and more distinct and the others faint. It happens over and below the horison.

Rays can go diffrent ways, yet still give the same result. It is shown for rays that do not change their direction (going straight from the Sun), and for those forming the Subsun.

The Sun is 23 degrees over the horison. The crystals shown here are deflected by 0, 15, 30, 45, 60, 75 degrees from the direction to the point situated on the horison below the Sun.

At the end you can see all light spots yielded by them. The spots are extremely strenthened. When light was refracted they usually look like a rainbow.