Why does Sirius twinkle with all the colors of the rainbow?

Sirius is the brightest star in the sky. At this time of year, the star twinkles iridescent, being low in the eastern part of the sky after sunset.

Roy Spencer from Huntsville, Alabama, has revealed a wonderful way to capture these colors by manually swinging his camera as he photographed Sirius.

A shutter speed of 5 seconds and defocusing was applied, the star was at an altitude of 15 degrees.

Astronomers call this phenomenon "stellar scintillation" (twinkling of stars). Bright light from a distant source passes through layers of the atmosphere that differ in density and temperature, which are similar to lenses that refract light. When the layers of cold and warm air drift in front of Sirius, the light from the star is refracted, and the prismatic action of the layers of the atmosphere leads to the appearance of rainbow colors.

All the stars twinkle, but Sirius especially because of its extreme brightness. The lower the star is to the horizon, the more it flickers, as light passes through a large thickness of the atmosphere, being distorted more.