22 Degree Halo Over Ponza, Italy

October 02, 2019


Photographer: Alessia Scarso
Summary Authors: Alessia Scarso; Jim Foster

Shown above is an eye-catching 22 degree solar halo over Ponza Island in Italy, as observed from my airplane window on April 7, 2019. Halos such as this one occur when sunlight is bent by randomly aligned ice crystals that are either free-falling in the atmosphere or constrained in cirrus clouds. Note that unlike rainbows, the red color is closest to the Sun. Also shown here are parhelia or sundogs having white tails extending away from the Sun. Sundogs always form at the same solar elevation as the Sun and are more conspicuous than halos since the crystals forming them are more aligned and tend to be larger than crystals responsible for halo formation. Always be careful when looking toward the Sun.

Photo Details: SONY ILCE-7RM3 camera; 1/1,000 sec. exposure time; ƒ/4; ISO 100; 35mm; composition of 2 photographs. Adobe Lightroom and Photoshop CC 2017 (Mac) were required to help with dust and window distortion.