Thursday, 9 December 2010

Column crystals halos on 8/9 December 2010

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Halos from column orientation were the main feature of this night in Tampere. In the beginning I was looking at the display with Luomanen but we did not have cameras. The display sort of took us off guard, it was thickly overcast and temperature at -5 C.  Anyway, Y-pillars were visible in Hervanta and we got crystal replicas at least.  Closer to the streelights beautiful circumscribed halos appreared, but it looked like there was some tilt involved. Columns with hollow ends in the replicas.

Later I continued on my own and took photos under streelight near Mustavuori.  Took also crystal photos - the crystals have become more equidimensional (the temp also had dropped to -7 C). Plenty of triangles (the photos above are all from this live sample) which probably have been falling in Parry orientation but Parry was impossible to distinquish under the lamp. Certainly triangular thick plates do not take plate orientations because there was no sign of plate halos in this display. Kern from triangular plates is only theoretical consideration.

For the last I went back to Hervanta where I photographed the Y-halo from the police training area floodlight. Also helic arc is visible. At some place there was also parhelia. The display lasted several hours and who knows how long it had been going on before we entered the scene.

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