Wednesday, 16 August 2006

HOP meeting 13 - 16 August 2006

Meeting of Halo Observation Project members was in Kuncice pod Ondrejnikem (Czech republic) - beautiful landscape of hills and woods. We had very nice observations of some rare halos: Parry suncave arc, 9 halos and 18 halos, on the high clouds. See PHOTO from Martin Popek. On photo from left to right: Vladimir Odvarka, Roman Manak, Lukas Kosarek, Jan Kondziolka, Martin Jankovic, Martin Popek and me. Photo was taken on meteorological station, Lysa hora.

Monday, 14 August 2006

Subhorizon diffuse arcs with Liljequist subparhelia

Francesco De Comité took this great photo from an airplane between Brussels and Madrid in 7 August 2006 at 19h31. Unfortunately no more additional photos are available from this display.

There is really well developed diffuse anthelic arcs crossing subparhelic circle. Subanthelion point is illuminated by these arcs. In this case it is clear that there is no subanthelion, since bright spot on subanthelion point has clearly square shape caused by diffuse arcs. Column ice crystals have to have good orientation.

Other very rare halo shown in this photo is broader segments on parhelic circle on both sides on subanthelion point. Unfortunately these broader segments are not very clear and they are cutted by edges of the photo. These broader brightenings are so called Liljequist subparhelia caused by plate ice crystals. Liljequist subparhelia have been photographed earlier at least by Walter Tape (see Tape's book Atmospheric Halos in page 71). Tape's display is very similar than this Francesco's display.

Since Francesco's display has rare halo made by plate ice crystals, it would be a really good case to look for still undocumented 120° subparhelia. Hunt for 120° subparhelia is still going on...