Colored Stars

For several months I've been noticing this extra-bright star in the sky and wondering what it is. After reading an article in our local paper I realized it must be Jupiter, which is visible until March. It is the third brightest object in the night sky, after the moon and Venus. It can be seen in the south, going from east to west, following the same path as the sun takes during the day. It won't come as close to earth again until 2022.

This is Jupiter close up; you can see its bluish tinge. After taking pictures I noticed that they showed different colors of stars and I wondered if that was just the photography, because I couldn't see colors when looking at the stars.

So I checked out Mr. Google and discovered that stars do indeed have colors according to their temperature. Blue, blue-white and white are the hottest stars and yellow, orange and red are the coolest. Blue is about 25x hotter than red.

This picture shows some of the different colors. You may need to double-click on it to see them better.

And it is true that our eyes do not perceive the colors when we look at the night sky. The reasons vary and are somewhat technical, but a simplistic reason would be that we do not see color at night. At night our pupils dilate to let dim light in and the resulting large aperture degrades image quality. Our eyes take about half an hour at night to reach maximum sensitivity.

In this picture I've increased the saturation to see the color better.

Taking pictures of the night sky is a challenge I'm still working on. If you photograph on an automatic setting the stars won't show. If you keep the shutter open too long, the stars will have tails because of their movement. After reading up a bit and experimenting I discovered that you have to focus manually and I increased the ISO to 1600 in these pictures.

I took these pictures at 4 a.m.! I wouldn't be doing that if it was -30! We've had such beautiful weather and it was relatively warm, although when I went back to bed it took me a long time to warm up! Even though it's dark in the evening the stars don't show up brightly until the middle of the night. Especially in town.

Now I'd like to get a beginner's book on stars so I can identify more!