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.

16 comments:

Tom said...

Hi,

it looks not really like a pollen corona, are you sure, thats not a corona on high clouds? Many sun eclipse observer have seen haloes. But however it is, the pic is staggering!!! Thanks for posting!

Reima Eresmaa said...

Hi,

yes, I am quite sure on the pollen. You can easily make an estimate of the radius of the corona by comparing it to the diameter of the Moon's disk. You will find the radius of the innermost segment to be around 0.3 degrees, which, as far as I know, better matches with the typical radius of a pollen corona than with the typical radius of a cloud corona.

In addition, the observers reported flowering pine trees in the vicinity of the observing site. No clouds were reported, though.

Anonymous said...

There were also slight clouds high up in the sky too, but there were large amounts of pollen in the atmosphere (This was confirmed by our very allergic friend who kept reaching for his handkerchief all the time during the solar eclipse).

Folks at Side had about equal amount of couds, but nobody there got this strong colour rings. We in Belek (me, Pasi Ojala, some hotel photgraphers...and perhaps couple of others in the are) seemed to be the only lucky bastards. It came to my mind that there was a small pine forest near the hotel district where as Side is a pretty much a plain beach. The
could wind which came with the totaly might have moved the pollen from those pines.

- EH

Anonymous said...

And one more thing: this image is pretty much in the original condition. we haven't changed the colours in any way. The only changes are image cropping (the focal length of the objective was only about 170 mm) and the text in the corner.

I didn't notice the pollen circle at the time of photography. This is mainly because I don't usually observe this kinds of phonomena and the intensity of a solar eclipse is so stunning that simultaneous, more subtle things are easily missed. One thing with a partial solar eclipse phase is also that everyone keeps repeating 'do not look at the Sun, do not look without any protection...'.

- EH

Marko Riikonen said...

I would not expect such a good corona from ice crystals. This is clearly pollen corona.

Les Cowley said...

One reason this corona is quite sharp is because the light source has a much smaller angular size than the 'normal' sun or moon. The source size effect is unimportant when the diffracting droplets or particles are less than 30-40 micron diameter because the resulting corona is then large compared to the sun disk.

However this corona was made by comparatively large 90 micron mean diameter particles or drops.

An IRIS simulation for spheres of that size and showing the effect of source diameter is at

www.atoptics.co.uk/point.htm

Does a diameter of 90 micron help identify a possible pollen source?

Les

Peter Kraemer said...

Hi,

we also watched the eclipse from a beach near Side. At 2nd contact, we noticed something like a pink-coloured glory around the diamond ring. As there were some cirrus clouds, which also had showed parts of the 22°-halo a short time before, we thougt that it came from the cirrus clouds.
Maybe we also saw a faint pollen corona without recognizing it.

Greetings
Peter

Les Cowley said...

To add further to Peter Kraemer's comment... We watched the eclipse somewhat east of Manavgat. The sky around the sun was cloudless but there were some clouds to the west. On the way back to the airport four hours later there were some of the brightest iridescent clouds that I have seen. Could be a coincidence - or maybe not.

Les

Marko Riikonen said...

Here are some pollen images and sizes, also Pine.

Les Cowley said...

I don't see a variety there Marko that is ~90 micron dia., reasonably monosized and sufficiently 'spherical' to be randomly oriented. But I'm sure there is a pollen that fits!
Les

Claudia Hinz said...

Thanks to Emma for this wunderful picture!!! It's a sun corona around the moon and reverse ;o)

I've read sometime, that the pollen radius of Pinus pinea are larger than from Central European pinus. But I'm not sure, if they blossom in the Turkey already so early. Do you ask the man with handkerchief, on which pollen he is allergic ... ;o)

Cordial greetings
Claudia

Marko Riikonen said...

Pine pollen corona is circular when sun high enough. The average size of the pollen surely varies with pine species, as Claudia says. Pine pollen, however, is not generally allegry causing agent at least in Finland, but perhaps the most sensitive individuals can get symptoms when enveloped in pollen cloud.

Les, what mean particle size and distribution you get for the pine pollen corona in my new posting?

Les Cowley said...

Marko,
Assuming that the green disk on your image is the sun then the corona can be matched by one produced by spheres ~46 micron mean diameter. How does that compare with pollen samples?

Marko Riikonen said...

I can't seem to find any info on our Pinus sylvestris pollen size from the internet. Anyway, here is great site for photos. You can even download a book of pollen, 574 pages.

On this site are photos of Pinus nigra pollen, that also grows in Turkey. The pollen size is referred as 51-100 um.

Anonymous said...

The guy with the allergy is sensitive to many various types of pollen, at least the finnish birch. So, that doesn't help us to determine the source. :-/

There were also some palm trees near the place where we were monitoring the eclipse. Those palms are clearly visible in this picture. Although the amount of pines in the vicinity was much larger.

The halo was visible in Belek too.

-EH

Günther Können said...
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