A halo appeared so prominently around the sun and remained there for
hours before disappearing. Many photos and Facebook updates appeared
during the morning hours, with the halo so clearly visible under the
Southern African sky.
The optical phenomenon consisted of a clearly visible rainbow that
appeared to be around the sun, with a large area between the sun and the
rainbow that appeared darker than the rest of the sky around the
rainbow.
These rainbows, or rings are caused by ice crystals that form within
cirrus clouds. Cirrus clouds usually appear at very high altitudes,
usually above 8000 meters or 26,000 ft. These clouds tend to be very
thin, due to the lack of abundant moisture at those altitudes. This type
of halo is also called a 22° halo, with the ring around the sun
appearing usually 44 times larger the sun.
The crystals that form in the clouds are hexagonal in shape, which
act as prisms for the sun’s light. It is important to remember to always
use a good set of sunglasses and to never look directly at the sun, as
even one moment’s gaze directly into the sun could cause permanent
damage to a person’s eyes.
Johannesburg is located within the province of Gauteng, South Africa
and usually enjoys a very pleasant climate with summer temperatures
ranging from about 15 – 30 degrees Celcius, and winter temperatures
ranging in the single digits to the lower teens. Johannesburg started as
a mining town in the 1800′s when rich gold deposits were discovered,
and has since grown to what is today known as the financial hub of the
South Africa.
The images below were captured while the halo still appeared around
the sun. You can clearly see the area between the sun and the halo or
rainbow appearing darker than the rest of the sky.