Re: Why don't stars near the horizon appear red like the setting sun does?

Starlight like sunlight gets scattered when the stars are close to the 
horizon and blue light does gets scattered more than the longer wavelength 
red light.  So stars do appear somewhat redder when they are close to the 
horizon. But stars are much dimmer than the sun and the effect is not very 
noticeable.  In addition, stars are so far away that they appear as point 
sources to us. When the starlight passes through lots of atmosphere when 
they are close to the horizon, we find that the air acts like a prism and 
breaks the starlight up into a spectrum.  Turbulence in the atmosphere and 
different density layers causes different colors to be refracted (bend) by 
different amounts.  That causes the twinkling of stars.  When the stars 
are very bright and close to the horizon, we see the twinkling as the 
flashing of red and blue starlight (as well as the other colors, but they 
are less noticeable).  The twinkling of the different colors overwhelms 
the slight reddening of the starlight and is much more noticeable.  It is 
especially noticeable in very bright stars like Sirius and Vega (at times 
also for the planets like Venus or Jupiter if there is lots of turbulence 
in the air).