Wednesday, May 10, 2006

Unknown halo in Germany

This archive picture photographed Dieter Klatt on october 25th, 1996 in Oldenburg (North Germany). It shows an upper unknown arc with faint 22° halo, right parhelia and a eft fragment of parhelic circle.


Blogger marko riikonen said...

The quality of the the photo is not very convincing. Claudia, can you give the sun elevation? And what about the lens? Some kind of wide angle thing that you screw on the normal lens?

I don't see parhelic circle, only short tail from right parhelion.

About the Lowitz - Parry connetion. Untill year 2000 we have 9 observations of Lowitz arcs without Parry arcs (many of them photographed). The Lowitz arcs from plate crystals should not have anything to do with Parry arcs, their co-occurrence is only coincidental.

10 May, 2006  
Blogger Claudia Hinz said...

Dear Marko,

unfortunately I give a better Scan from the original slide, the halo was not so bright.

Sun Elevation: 21°
(Oldenburg, 25.10.96, 13.46 CET)

I Germany we had only two cases with upper Lowitz without Parry, the second is here

Both observations are very old, until 2000 we (ca. 30 obersevers in complete Germany) have never seen this case ;o)

It seems to me very strange, but if it's in your opinion an ordinary phenomena in too bad quality, of course I can delete this posting.


12 May, 2006  
Blogger marko riikonen said...

It's definitely worth knowing this observation. It's just that the thing looks so odd and the photo is not exactly the top notch quality. But now as you gave the sun elevation, we can perhaps say something more definitive about it on the basis of simulations. I'll see about it later.

12 May, 2006  
Blogger marko riikonen said...

Here is a comparison of the Klatt photo with Lowitz simulation that I made. The Lowitz arcs don't quite match with the halo in the photo. It's likely that the projection is not exactly the same in the photo and simulation, but the difference should not be too big. So I am puzzled about what's going on in the photo. The photo superposed with simulation seems to reveal some asymmetricity in the halo, which suggests it might not be a halo at all.

The simulation is made with HaloSim by Les Cowley and Michael Schroeder.

14 May, 2006  

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