Twinkling star Spica and red planet Mars.
Atmospheric turbulence causes the brightness and color of the star to vary more readily than that of the planet. This is because the star is effectively a point source while the planet, being much closer, is an extended source of light. The more light we receive from a source, the more stable its average brightness and color is.
Date: July 12, 2014
Location: Roque de los Muchachos Observatory, La Palma
Camera: Canon 6D
Lens: Canon EF 70-300mm f/4-5.6 IS USM (at 300mm, f/5.6)
Exposure: 6.4 seconds at ISO 3200
Processing: Processed in Photoshop CS6