I was wondering why do some stars show more then one color?
I do not have a telescope but I use my binoculars and I see a bunch of
colors going around these stars one at a time. The colors are red, blue,
white, green, yellow, violet (colors are not necessarily in this order).
All stars have a single color, though that changes over very long periods
of time. They my appear to change color quickly because of the unsteadiness
of Earth's atmosphere, but those changes are not real.
Stars emit a variety of wavelengths of visible light. The eye is not
sufficiently sensitive to distinguish these various wavelengths (colors).
The "colors" you see when using binoculars is due to distortions in the
lenses of the binoculars, which cause the incoming light to focus at
slightly different positions in the optical path (including the eye).
Without specialized equipment to disperse the incoming light all stars
appear approximately "white" to the eye. Again, what you are seeing has
to do with the optics of the binocular and not the properties of the
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Update: June 2012