Tuesday, March 06, 2007

Odd radius halos in diamond dust in Finland

On 23 February an another diamond dust display with odd radius halos occured in Vaala, Finland. Temperature was dropping from -29°C to -24° during my observation.

A parhelic circle and circumzenithal arc were present with nice parhelia. A subsun and subparhelia were also seen as sparkling ice crystals in front of the ground.

Odd radius halos labelled in this enhanced photo are A) a pyramidal heliac arc, B1) upper 24° plate arc, B2) lower 24° plate arc and C) upper 23° plate arc.

The most brightest odd radius halo was 18° halo and in some photos there probably are also 9° upper plate arc and 20° halo. The ice crystal cloud was produced by a local heating plant about 2 km away. More photos can be found here.

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Blogger Michael Ellestad said...

Did you get any crystal samples?

07 March, 2007  
Blogger Jarmo Moilanen said...

Unfortunately not.

I did all these diamond dust observations in February during my working day. I do not have any good way to keep my crystal sampling equipments with me during my work hours. I need to get that problem solved. This was a really interesting oppornity to get crystal samples. I missed it now.

07 March, 2007  
Blogger Michael Ellestad said...

Well as they say there is always a next time.

10 March, 2007  

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