Friday, June 23, 2006

Pine pollen corona in Finland

Continuing on the favorite topic of pollen coronas, here are two rather painstakenly constructed images of pine pollen corona.

The white dots are wind dispersing seeds, probably of some willow species. They are more abundant in the lower image, which was taken in town. The upper image was shot in the midst of pine heath, with correspondingly less white fluffs in the air.

On 13. June 2006 in Eastern Finland. Larger sized versions are here.

Thursday, June 22, 2006

Miraged Ships

On June 11, 2006, Thorsten Falke and his girlfriend Bärbel Wichmann decided to have a picnic at the south-beach of Düne, a one square kilometer little island in the North Sea and in the neighbourhood of Heligoland.

Even though the picnic basket contained several tasty titbits the sky was even more tempting with its unusual mirages. Ships passing Heligoland and Düne at a distance of 10 km or more appeared somehow "stretched". They looked longer than they really were.

Thorsten and Bärbel are still wondering how this effect come about. The sun was shining the whole day and because there was almost no wind, a warm air layer probably lay above the water surface. They suggest that when a ship is on a course of 45° (for example) towards or away from the observer, the bow of the ship is closer/further to the observer than the stern. This, combined with the warm air layer, may cause the unusual extension/or sometimes shortening of the ship.

The two images are 15s apart. More mirage images here.

[Text: Thorsten Falke & Bärbel Wichmann]

Tuesday, June 20, 2006

Pollen corona during solar eclipse

A pollen corona was seen by several observers at the Southern coast of Turkey during the total solar eclipse of 29th March 2006. This nice picture taken by Emma Herranen shows the atmospheric pollen corona with three colour segments only a few seconds before the second contact, as illuminated by the diamond ring phenomenon. The inner parts of the solar corona are seen as a white circle around the Moon.

Thursday, June 15, 2006

Colourful refraction by the surface waves

On June 13th Thorsten Falke from the German North Sea isle "Düne" (near of isle "Helgoland") was walking along the seashore, when he saw criss-cross light structures on the seabed obviously caused by refraction by the surface waves. He had seen the phenomena often before but this time it seemed to be coloured. He decided to paddle out into the water to take pictures. It was difficult to see the colours visually because of the rapid movement of the little waves (only 2 cm "high") but in many of the pictures the colours were evident. The appended picture was taken with a macro lens and shows a shell in 10 cm deep water with a colourful refraction band across it. Because of the macro lens the picture is nearly 2 times life size. Another refraction is located at the upper edge of the picture. If he remembers rightly, the light was coming from the left side and was parallel to the wave crests. The main interest of Thorsten is to observe whether the colourful refraction is seen only when the wave crests are parallel to the light direction or if it is also visible when the crests are at right angles to the sunlight.

Tuesday, June 13, 2006

Cedar Pollen Corona

I saw this extremely splendid cedar pollen corona on May 19, 2005 at Hachioji, Tokyo. Last year, the amount of cedar pollen was so large that we could observe some beautiful coronae (but it was a nightmare for people caught by hay fever).

Cypress pollen is another source of pollen coronae in Japan. However, the season of Japanese cypress pollen is almost same as that of our cedar pollen so that it is hard to distinguish its contribution from the cedar pollen's contribution. (The amount of cypress pollen is less than cedar pollen.)

Saturday, June 03, 2006

Subhorizon rainbow

This deep-subhorizon part of a rainbow was photographed by Günther Können on 2 Oct 2005 on a flight from Amsterdam to Madrid. Although cloudbows are frequently seen from an airliner, rainbow sightings are relatively rare. To my (Günther's) experience, the best chances are when the altitude of the plane is not too high. It was the second time that I saw such a distinct one, the first time being 23 yr ago.

Pollen Corona by a False Acacia

In Japan, pollen coronae are normally caused by ceder pollen (and possibly Japanese cypress pollen). However, a pollen corona by a false acacia is observed by Mr. Yasuike on May 25th 2006, in Matsumoto. He said that an amount of false acacia pollen is quite large in this season around Matsumoto (it is not typical for the other areas in Japan).
It might be the first report of a pollen corona in Japan, other than by ceder (or cypress) pollen.