Bad Honnef · A rare weather event, a so-called halo phenomenon, was photographed by a GA reader on Friday afternoon in the sky over Bad Honnef: What was the reason for this?
When Rolf Herzbach looked up into the almost cloudless sky above Bad Honnef on Friday afternoon at about 2.30 p.m., he saw a rare weather phenomenon: the appearance of a so-called halo phenomenon. A circular line had formed around the sun, so that when the GA reader sent in the photographs, he jokingly reported seeing a “corona sun”. This is a very appropriate description, because the outer layer of the Sun's atmosphere or a ring-like luminous phenomenon is also called a corona (from the Latin).
After viewing the images, the German Weather Service (DWD) in Offenbach confirmed that they were of a small solar halo phenomenon. “In the region around Bad Honnef, the cirrus cloud sky on Friday afternoon provided favourable conditions for the formation of a halo phenomenon,” said Olaf Pels-Leusden of the DWD. The ring around the sun was formed by the refraction of the sun's rays in the small ice particles of the cirrus clouds (high, thin-layer clouds), the metereologist explained.
In addition to the appearance of small halos, large (and even rarer) events can also occur, such as the presence of mock suns (parhelia) and mock-sun haloes, and white columns of light, amongst others. All celestial phenomena are caused by light refractions in the differently structured ice particles in the clouds. Pels-Leusden explains that the haloes described above can also occur in moonlight.
Other GA readers also reported seeing the “Corona Sun” in Königswinter, for example.
(Original text: Dierk Himstedt, Translation: John Chandler)