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Date: | Fri, 17 Apr 2015 12:18:42 -0500 |
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There actually are different colored stars but their
colors come from their temperatures so they usually emit a broad
range of colors just like our own Sun but the hotter stars have
a peak that is higher or shorter wave-length than are the cooler
stars. A star like our Sun is considered to be an average
run-of-the-mill star. It is in the middle of it's life cycle so
it has about as long to shine as it has already shown. It's
surface temperature and the fact that we are not moving toward
or away from it at any real speed determines what color
Earthling see.
When you heat something such as a piece of metal, it
starts to glow reddish-orange around 1,000 or 2,000 degrees.
Electric stove burners on high and tube filaments glow this
color.
If you raise the temperature up to around 6 or
7-thousand degrees, the light is more Sun-like. We would call it
yellowish-white. If you keep heating the metal, it shines more
blueish and eventually goes violet.
Welding torches emit a lot of ultraviolet and are
hazardous to one's eyes because of this high temperature. If you
could keep heating things up high enough, the object you were
heating would be sending out X-rays and gamma rays.
There are stars that are huge by our Sun's standard and
they actually shine in X-ray light because they run so hot.
Other stars run cooler than our Sun and might look more like a
glowing log in a dying camp fire.
The smart people in astronomy say that our Sun will
probably die one day by expanding to something called a red
giant. It will basically cool off so that it's light is more
red-orange and it will most likely also expand in size to eat
our whole Solar System.
Each hot object, whether or not it is a star or a light
bulb filament emits a whole rainbow of colors but some are much
stronger than others.
What you saw with the binoculars is something called
refraction. Lenses cause this effect because different colors of
light are refracted at different angles so everything has a
halo of rainbow color around it.
That is one of the reasons telescopes use parabolic
mirrors instead of lenses. Mirrors that are front-surfaced do
not refract light but reflect it and all the colors get to your
eye or your camera in the right place so a white star looks like
a white point of light rather than a very pretty but inaccurate
rainbow point.
Martin
Phil Scovell writes:
> I am buying the N4PY software for my Icom 7000, which works on Kenwoods,
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