Solar Halo Over Thessaloniki, Greece

June 10, 2020


Photographer: Christina Irakleous 
Summary Authors: Christina Irakleous; Jim Foster

Featured above is an amazing 22 degree halo I observed above Thessaloniki, Greece, during the late morning on April 16, 2020. A contrail nearly bisects the solar disk – its shadow is just below it. Ice crystals that compose cirrus type clouds are responsible for such halos. If they’re randomly oriented, the crystals refract sunlight in such a way to form a circle. More colorful halos result if crystal sizes are larger than average (approximately 0.1 to 0.2 mm across). Note that a streetlight is used here to block the light of the Sun. Always use extreme caution anytime you look anywhere near the Sun.

Photo Details: Camera: Canon EOS 600D; Software: Adobe Photoshop CS5 Windows; Exposure Time: 0.0003s (1/4000); Aperture: ƒ/5.6; ISO equivalent: 100; Focal Length: 18.0mm.