As stated in other articles, I have only been an active amateur astronomer since March 1997. However, in those few short years, I have noticed a real deterioration in the darkness of the night sky. To me there was a major change in 1999, and it has not gotten any better.
Until July of 1998, all of my viewing was done from Ford Field in Dearborn [Dearborn, Michigan], the outskirts of the city of Frankfort Kentucky, or the Ford AAC viewing site at Island Lake [also located in Michigan], so it was not really possible to get a real good object evaluation of the sky quality (plus, I was trying to learn what good “seeing” meant).
In 1998 we moved to our current home on Parker Road in Freedom Township, and I discovered what “Country Skies” could be like. Not Arizona desert or Colorado mountain skies, but they certainly appeared black to me, especially after 2:00 AM.
I have found that to be the magic hour when the darkness of the skies seems to improve, (to me at least), at every place I have viewed. Granted that I have done almost all of my viewing from Urban or near Urban sites, but it seems that a lot of advertising lighting must go off about that time (3:00 AM for some of it during DST).
However, since late 1998, early 1999, without time for wholesale major increases in lighting near our home, or in this general area, the night skies are not “black” any more. A dark charcoal gray seems to be about as good as they get, even at the rare times I have been to Lake Hudson [Located in Southern Michigan]. The Earth has experienced numerous volcanic eruptions and major fires (e.g. Mexico, Florida, the U.S. West), since 1998 that seem to have left a still lingering haze in the air.
To check this out, all you have to do is take a very powerful flashlight and/or spotlight outside some night and shine it straight up, any time of the year, (excepting during Star Parties or viewing sessions with others present, you could get the light put where it will hurt). The amount of particles in the air is shocking, and probably a quick answer to why our area skies are not really black at night.
It seems to me that this “dirty air”, with all of the South East Michigan lights bouncing off of it, is a large contributor to our skies being various shades of gray, not black, except for very rare occasions (there is noticeable improvement after major windy periods, which leads me to believe that this “dirty air”, plays a large role in the darkness of our local skies).
In the book Orbit, a collection of great astronaut photographs from space, astronaut Dr. Jay Apt, states (page 128), that on his first mission, in 1991, the sky appeared very clear. On his second mission in 1992, less then 2 months after Mt. Pinatubo, in the Philippines exploded, the ascending shuttle went through 2 separate layers of volcanic dust at about 100,000 feet of altitude. He felt that this dust made a real difference in the quality of Earth viewing on that mission.
Well, we can’t do anything about volcanoes erupting and very little about major fires in our country and others (except to make sure we never start any), so what is the point of this article anyway?
1. A Question: Have any of you longtime astronomers out there noticed a decrease in local sky darkness that you can attribute to “dirty air”?
Yes, I know that we have had megafold increases in the amount of light output in this area and across our country in the last few years, which gets reflected and bounced around in whatever atmosphere is present. But, it seems to me that if the air were cleaner, that would help the darkness of the sky also.
I would like to hear the thoughts of others on this subject. Perhaps we can discuss this issue at the Club some time.
2. We can, of course, support the Dark Sky Association and other dark sky efforts. Tell your elected officials.
3. We can support efforts to clean up the air pollution. Again, tell your elected official, at all levels.
4. Mark was desperate for articles.