Abstract

On 5 June 2008 there was a rare display of eight concentric halos in Tampere, Finland. I present a preliminary analysis of this display. A brief comparison with earlier major odd-radius displays is made. Short faint arcs intersecting the Sun and their resemblance to the theoretical odd-radius helic arcs are discussed. A stacked image consisting of 72 individual frames of the display is presented. A single frame is provided for comparison, and the visual observation is described in some detail. Postprocessing techniques for halo photographs are discussed. A stacked simulation and the relevant crystal populations are presented.

© 2008 Optical Society of America

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References

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  1. Ursa Astronomical Association's halo mailing list archive 2008; from 5 June 2008 onward, http://www.ursa.fi/ursa/viestinta/listat/ilmakeha2-l/summary.html.
  2. W. Tape and J. Moilanen, Atmospheric Halos and the Search for Angle x (American Geophysical Union, 2006).
    [CrossRef]
  3. M. Riikonen, “Distinction of 22, 23, and 24° halos from snow surface,” http://www.ursa.fi/blogit/ice_crystal_halos/index.php?title=distinction_of_22_23_and_24d_halos_from_&more=1&c=1&tb=1&pb=1 (2008).
  4. M. Pekkola, M. Sillanpää, and J. Ruoskanen, “Valkean taivaan vieraat. Tähtitieteellinen yhdistys URSA, Helsinki” (1998).
  5. J. Ruoskanen, “Riihimäki 5.6.2008,” http://www.kolumbus.fi/jukka.ruoskanen/Halot/050608/index.html (2008).
  6. J. Luomanen, “Pyramidal halo display 05 June 2008, Tampere,” http://www.kolumbus.fi/jari.luomanen/x-ilmakeha/atmosphere1497-1537.html (2008).
  7. M. Riikonen and J. Ruoskanen, “Stacking technique in halo photography,” presented at the Ninth International Meeting on Light and Color in Nature, Bozeman, Montana, USA, 25-29 June, 2007.
  8. J. Luomanen, “Pixel workout - exposure, histogram, and bit depth in halo photography,” presented at the International Halo Meeting, Artjarvi, Finland, 14-16 July, 2006.

Luomanen, J.

J. Luomanen, “Pyramidal halo display 05 June 2008, Tampere,” http://www.kolumbus.fi/jari.luomanen/x-ilmakeha/atmosphere1497-1537.html (2008).

J. Luomanen, “Pixel workout - exposure, histogram, and bit depth in halo photography,” presented at the International Halo Meeting, Artjarvi, Finland, 14-16 July, 2006.

Moilanen, J.

W. Tape and J. Moilanen, Atmospheric Halos and the Search for Angle x (American Geophysical Union, 2006).
[CrossRef]

Pekkola, M.

M. Pekkola, M. Sillanpää, and J. Ruoskanen, “Valkean taivaan vieraat. Tähtitieteellinen yhdistys URSA, Helsinki” (1998).

Riikonen, M.

M. Riikonen, “Distinction of 22, 23, and 24° halos from snow surface,” http://www.ursa.fi/blogit/ice_crystal_halos/index.php?title=distinction_of_22_23_and_24d_halos_from_&more=1&c=1&tb=1&pb=1 (2008).

M. Riikonen and J. Ruoskanen, “Stacking technique in halo photography,” presented at the Ninth International Meeting on Light and Color in Nature, Bozeman, Montana, USA, 25-29 June, 2007.

Ruoskanen, J.

M. Riikonen and J. Ruoskanen, “Stacking technique in halo photography,” presented at the Ninth International Meeting on Light and Color in Nature, Bozeman, Montana, USA, 25-29 June, 2007.

M. Pekkola, M. Sillanpää, and J. Ruoskanen, “Valkean taivaan vieraat. Tähtitieteellinen yhdistys URSA, Helsinki” (1998).

J. Ruoskanen, “Riihimäki 5.6.2008,” http://www.kolumbus.fi/jukka.ruoskanen/Halot/050608/index.html (2008).

Sillanpää, M.

M. Pekkola, M. Sillanpää, and J. Ruoskanen, “Valkean taivaan vieraat. Tähtitieteellinen yhdistys URSA, Helsinki” (1998).

Tape, W.

W. Tape and J. Moilanen, Atmospheric Halos and the Search for Angle x (American Geophysical Union, 2006).
[CrossRef]

Other (8)

Ursa Astronomical Association's halo mailing list archive 2008; from 5 June 2008 onward, http://www.ursa.fi/ursa/viestinta/listat/ilmakeha2-l/summary.html.

W. Tape and J. Moilanen, Atmospheric Halos and the Search for Angle x (American Geophysical Union, 2006).
[CrossRef]

M. Riikonen, “Distinction of 22, 23, and 24° halos from snow surface,” http://www.ursa.fi/blogit/ice_crystal_halos/index.php?title=distinction_of_22_23_and_24d_halos_from_&more=1&c=1&tb=1&pb=1 (2008).

M. Pekkola, M. Sillanpää, and J. Ruoskanen, “Valkean taivaan vieraat. Tähtitieteellinen yhdistys URSA, Helsinki” (1998).

J. Ruoskanen, “Riihimäki 5.6.2008,” http://www.kolumbus.fi/jukka.ruoskanen/Halot/050608/index.html (2008).

J. Luomanen, “Pyramidal halo display 05 June 2008, Tampere,” http://www.kolumbus.fi/jari.luomanen/x-ilmakeha/atmosphere1497-1537.html (2008).

M. Riikonen and J. Ruoskanen, “Stacking technique in halo photography,” presented at the Ninth International Meeting on Light and Color in Nature, Bozeman, Montana, USA, 25-29 June, 2007.

J. Luomanen, “Pixel workout - exposure, histogram, and bit depth in halo photography,” presented at the International Halo Meeting, Artjarvi, Finland, 14-16 July, 2006.

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Figures (5)

Fig. 1
Fig. 1

Crystals used in the simulation.

Fig. 2
Fig. 2

Stacked image with 72 individual frames of the display.

Fig. 3
Fig. 3

Close-up detail showing the separation among the 22, 23, and 24 ° halos.

Fig. 4
Fig. 4

Single frame for comparison with the stacked image in Fig. 2.

Fig. 5
Fig. 5

Simulation of the display superimposed against the curving horizon and the Sun filter.

Tables (1)

Tables Icon

Table 1 Crystal Populations Used in the Simulation and the Corresponding Halo Forms

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