Sunday, July 8, 2007
If you've read Derek's post of July 2, you'll remember his reference to Crater Lake and the dark night sky with a multitude of stars. Click on the picture for a larger view of what it looked like.
If you look at this picture in bright surroundings, you will see quite a bit less than what is actually in that picture. This is very similar to the "light pollution" which, in cities, is caused by street and house lights throwing unnecessary and otherwise unused light into the night sky, rather than onto the ground where it would do some good. If people were to use sufficiently shielded, correctly pointed, and motion sensor triggered lights, a fair percentage of this pollution could be avoided. You would also save money, since properly directed light would mean that fewer lights are needed in the first place. Light pollution is a big problem for earth-based deep space astronomy. Many people living in cities have never seen the Milky Way, nor any of the other phenomena in the sky which can only be perceived when the night sky is really dark. Look at the picture in a room with subdued light, and you'll be amazed how much more you can find.
Here are some more pictures which may interest you: