While sub-Kern was strong in the 7/8 December display, the Kern arc was less so. For one thing, I did not see it visually. In the two photos showing it, it can hardly be distinguished from the overlapping heliac arc. The other one of these photos is shown here. On the right is a heavily enhanced version zoomed at the zenith region.
-
Recent Posts
Recent Comments
- Jill on Complex halo display in Destne
- Elmar Schmidt on Odd radius halo – 2 April
- Dominique Morisseau on New book on halos
- Michael on Helic and Tape arc in Cirrus
- David Johnson on Subhelic arc in Finland
Archives
- April 2012
- January 2012
- October 2011
- September 2011
- June 2011
- May 2011
- January 2011
- December 2010
- November 2010
- October 2010
- September 2010
- August 2010
- July 2010
- June 2010
- May 2010
- April 2010
- March 2010
- February 2010
- January 2010
- December 2009
- November 2009
- October 2009
- September 2009
- August 2009
- July 2009
- June 2009
- May 2009
- April 2009
- March 2009
- February 2009
- January 2009
- December 2008
- November 2008
- October 2008
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- August 2007
Categories
Meta
Strange how that the regular Kern is faint and hard to see but the sub-kern was strong and easy to see. Theres something about those subhorizon halo raypaths that makes arcs like sub-Kern brighter. I just don’t get it.
A light ray does not travel easily 1-3-5 raypath that makes Kern. Before it reaches face 5, it is likely to meet another face and thus contribute to another halo. But with sub-Kern raypath 1-3-2-5 reaching face 5 is easier because of the basal face reflection before that. This is why sub-Kern is brighter.
Solution for more intense regular Kern is to make plates thicker (even column-like) or make them triangularish.
In this photo, contrary what I wrote, actually the Kern might not be that much overlapping with helic arc, but rather continuing it (imperfectly). Compare to previous posting photos.