|Lowitz Arcs, Germany
One of the finest images of the once controversial Lowitz arcs. See below for a key to the three Lowitz components. Taken by Thomas Klein on November 1, 2014 at Miesbach, South Germany. Lowitz arcs were only part of this magnificent halo display with many other rare arcs.
All images ©Thomas Klein, shown with permission
|The colour subtraction enhancement at left of Thomas Klein's image shows an unusually complete set of Lowitz arcs. Most unusually, the upper and lower Lowitz arcs are seen to cross and extend beyond the sundog. The middle arc - rarely seen - extends above and below the sundog.|
22° Lowitz arc formation - There are three ray paths between plate crystal side faces giving upper, middle and lower arcs.
|A display that deserves to go down as one of the great ones.|
|A colour subtraction enhancement of the display made by Thomas Klein. It shows very rare (from Natural crystals) Parry supralateral (Tape) arcs. More tellingly, it shows 46° Lowitz arcs. One of them could be confused with a 46°circular halo fragment from randomly oriented crystals.
The HaloSim ray tracing at left shows all Lowitz arcs in red. The outer (46°) arcs are from rays traversing a crystal basal face and a hexagonal prism side face.
One of Thomas's images show a 'helic' arc - a form of this can also be generated by Lowitz crystals.
|Lowitz first recorded (in 1790) a lower arc stretching from the sundog to the 22 degree halo. Perhaps that is why the traditional place to search for them was near sundogs. Perhaps that is why they were controversial until the 1990s. In fact, the upper arc is most easily observed as it crosses the upper tangent arc to meet a Parry arc.|