Frosting Light Diffraction Patterns

When looking at the sun through the frost patterns on the windshield of my car on May 4, 2014, I saw a well-defined yellow and red corona. The ice crystals on the window pane worked as an obstacle which diffracted the light, which means they deviated it into different directions. So the light waves can reach areas which are blocked out when following the direct way. A diffraction pattern always consists of bright and dark spaces. The dark spaces are those where waves extinct each other, while the bright areas are at the positions where the light waves add each other. Coronae which are really circle-shaped form in grids with periodical gaps as for example in fabric. Irregularly collocated diffracting particles, however, form coronae which change their shape significantly when seen from different angles (1–2).

Author: Claudia Hinz

Colourful flies leg

Since a short time I ever and again go down into the microcosm, a very interesting and colourful world. A lot of optical phenomena in the sky can also be found in this little world. The origin of the colours are usually diffraction and interference. Actually it´s no wonder, that these tiny structures are able to bend the light. So it´s probably possible that the bristles of a flies leg get colourful. Well, I think, I should analyze the hairs on my legs, too.. . 😉

The compound eye shows interesting effects as well and the wings anyway. Some flies have seemingly a gold foil between the eyes.

More pictures of my journey into the microcosm can be found here: – 1 – 2 – 3 – 4 – 5

Author: Sven Aulenberg, Saarburg, Germany

Compound Eye of a Horsefly

July 11, 2008:

I was very astonished when I was working and suddenly a horsefly fell upon my workbench.
The animal was about 3.5 cms in length. It was a very hot day, and the “flying fellow” had obviously lost his way, landed up in the workshop and could not find the way out. Well, the animal was lying there without moving, and the sunlight caused nice diffraction colours in its big compound eyes.

Author: Michael Großmann, Kämpfelbach, Germany

Silver Fir Diffraction

The photo here was taken by Mónika Landy-Gyebnár. It shows light through the branches of a silver fir with thick, short grown needles. The camera was looking towards the sun and out of focus – just like in the spider web post of September. The curved structure is caused by diffraction. The image shows well-visible colours, and what makes the photo even more interesting is the horizontal lines across these coloured bands. Could it be some interference pattern created by the less spectacular slanting stripes on the side of the image? Or something else? More pictures

Author: Ágnes Kiricsi, Hungaria

Flag corona

Light diffraction doesnt only originate from aerosols like little water droplets or pollen floating freely in the atmosphere, but also from so-called diffraction gratings. These consist of a large number of equally spaced holes or slits, from which the light rays interfere and form an interference pattern. In this example, which I photographed in the beginning of April, the thick woven fabric of the European flag serves as a diffraction grating and shows a beautiful corona.

Author: Claudia Hinz, Brannenburg, Germany