The Rainbow Star, 2016 (digital photo)

Creator: Steven Brown Stars appear to twinkle because their light is affected by variations in air density as it passes through the Earth's atmosphere. As starlight travels between these layers, it is refracted or bent and it seems to zig-zag its way through the atmosphere. This twinkling effect, or astronomical scintillation, is more obvious for stars than other heavenly bodies because of their point-like appearance. In this image a star, Sirius, is the brightest in the sky. At just eight light years away, it is also one of the closest stars to Earth. Like all stars, Sirius emits light of many colours, which refract by different amounts. The brightness and low position of Sirius in the sky make the twinkling effect and variations in colour more obvious to the stargazer. Born digital photograph 'The Rainbow Star' by Steve Brown, dated 11th January 2016, taken on Stokesley, North Yorkshire, Taken with a Canon EOS 600D camera wiht Star Adventurer tracking mount, 250 mm lens, ISO 3200, stacked 70 of 1500 frames Winner of the Stars and Nebulae category of Astronomy Photographer of the Year 2016