Putting your binoculars or scope (or in this case your camera) slightly out of focus helps to detect color differences in stars. Arcturus is a red giant sun with a surface temperature of 4,000°C. Spica is a blue giant sun with a temperature of over 25,000°C! (for reference, our sun's temp is 5,600°C) Of course it doesn't feel that warm if you're in Buffalo, N. Y. during January.

Canon EOS M10
24mm, f3. 5
8s, ISO800