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STARGAZING by Tony Flanders
Pollution and Stargazing
When I went out to check the sky around the end of nautical twilight, my first impression was that the clouds had gone and the stars had come out. But after I'd dark-adapted for a few minutes, I realized that something was wrong. Although the sky was completely cloudless, there were nowhere near as many stars as there ought to be that late in the evening, and even the brightest stars lacked a certain vibrancy. But as I've said before, stargazers in the eastern U.S. can't afford to be picky. Rather than hauling out my 12.5-inch scope, I decided to compromise and use my 15×70 binoculars.
It turned out to be a surprisingly gratifying night of stargazing. Though the Milky Way remained lackluster all night, I got altogether respectable views of many deep-sky objects. I'm trying to get to the point where I can locate and recognize all of the Messier objects without charts, by memory, and 15×70 binoculars are perfect tool for this job. They're big enough to pick up almost all the Messier objects effortlessly, even in so-so conditions, and it's easy to scan the sky with them.
After sorting through the globulars in Ophiuchus one of the few Messier groupings that I haven't fully mastered I moved on to the summer Milky Way, and had a splendid time. I even picked up a fair number of 8th- and 9th-magnitude non-Messier star clusters by pure accident. (Remember, I was mostly working without charts.) No doubt about it, a so-so night in the country beats a superb night in the suburbs hands down.
It's well established that most of the summer haze in my part of the world is caused by air pollution, primarily from power plants and vehicular exhaust. Nature plays it's role too. High humidity helps, though in fact it hadn't been humid at all that night. And forest fires, dust storms, and volcanoes can pump junk into the atmosphere much faster than humans can. But those phenomena are intermittent, while anthropogenic air pollution is ceaseless and relentless.
It's a bit of a paradox. I drive to dark locations to get away from light pollution, but in doing so, I'm contributing far more than my fair share to air pollution, which can be nearly as serious an obstacle. I still haven't really come to terms with that.
Posted by Tony Flanders, July 17, 2007