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Light Pollution (was Re: Meteor Shower)
Posted By: Lucky Wizard, on host 4.60.250.177
Date: Saturday, September 1, 2001, at 16:37:21
In Reply To: Re: Meteor Shower posted by Ellmyruh on Friday, August 10, 2001, at 00:23:09:

> > I've had to miss it the past five years, because of weather or being trapped in light-polluted cities. This weekend, Mike and I are going camping in the mountains. If it's cloudy, and I miss the shower for the sixth year in a row, I'll probably combust.

> Of course, I'm NOT near the clear skies of New Hampshire this weekend! The combination of air and light pollution in a city makes it appear that there aren't as many stars in the sky, and I was reminded of that on my recent New Hampshire visit. I grew up being able to see the Milky Way and, according to a recent CNN article (link below), I'm not the only one who misses it.
>
> I've been trying to see the August meteor showers for years now, and the last time I saw anything like a real meteor shower was nearly 10 years ago when I lived in a non-city area. I camped out on the back porch and counted 17 shooting stars before I started seeing bats swooping over head.

Anybody here familiar with APOD? It's a great site. Its full web hypertext system introduced me to several sites (which I don't visit regularly, but once in a while if I want to.)

A recent APOD discussed that very subject. (Actually, there are other APOD's that have discussed that subject. But I'm pointing out a recent one because it introduced me to a couple of web pages related to this very subject.) Here is the URL:

http://antwrp.gsfc.nasa.gov/apod/ap010827.html

I checked the last two links on this APOD's explanation:

http://www.darksky.org/ida/infoshts/is122.html
http://www.pha.jhu.edu/~atolea/second/page1.html

These links are quite relevant to the conversation. Now, as for personal experience...

I live in a suburb of Portland, Oregon. Where I live is about 10 miles from Portland's city limits (estimate). (I live in the westside. Yes, the westside is where they're experiencing unrestrained development...) Sometimes, I go to Portland during an errand or some such. Of course, I'm usually at home when night falls. But if the reason I'm in Portland is to see a night baseball or basketball game, then I'm usually still in Portland hours after dark.

(Note: After this point, when I refer to seeing a constellation, it means that I am identifying enough stars to be fairly certain that it's the constellation I think it is.)

Comparison: When I'm in Portland at night, the city lights prevent me seeing all but the brightest stars. I do, however, see the occasional bright star. I can't even see any constellations.

But when I'm at home, I can see better, (and have seen a few constellations), but I still can't see the Milky Way (or any of the dimmer naked-eye-visibility stars). Perhaps the best way to compare would be to describe the fact that, on the way home from a basketball game about a year and a half ago, I was watching the sky. As we left the Rose Garden (oh... that's in the east part of downtown Portland, by the way), we couldn't see many stars (only the brightest ones, in fact). As we travelled west, we emerged from Portland, and soon were in an area which isn't as heavily lighted as downtown Portland, and I could see several constellations. (In fact, I could see the constellation Leo for the first time.)

I don't go to rural areas often, and it's rare for me to be in one at night. But, a few weeks ago, I was in Michigan. Specifically, I was staying in Jackson, which is one of these cities with a population of 40,000 people that's not near many larger cities. And, we kept going to the area of Napoleon and Brooklyn. (Those are two towns, some distance SW of Jackson, that have a population which is only slightly greater than 1,000 people. The nearest cities to Jackson that are larger than Jackson are 30 miles away. When we went to Napoleon and Brooklyn, we were heading away from the large 30-mile-away cities.) And we didn't go just that far; we went farther. We were running a lot of errands in one day, and we wanted to keep on Pacific time, so we kept staying up until about 1 AM where we were. So, that day, I had an opportunity to stargaze for some time (and since I spent some time that night in an area where the only cities have a population of 1,000 people, I used that opportunity.) I *think* I may have seen the Milky Way for the first time, and I also, for the first time, saw enough stars in Lyra to enable me to classify it as a constellation I've seen. As I approached Jackson, I became unable to see the thin, misty band, which was either a cloud, the Milky Way, or my imagination (it was extremely faint when I did see it).

As an afternote, I'll note that most of the lighting fixtures that I see in my hometown are drop-lens cobra heads, acorn ornamentals, and sag-lens luminaires (identified as bad by the International Dark-Sky Association) and flat-lens shoeboxes and flat-lens cobra heads (identified as good by the IDA). So far, the bad seem to outnumber the good, but since I first saw flat-lens cobra heads today, I'm beginning to think the good will eventually replace the bad.

Lucky "Ok, so parts of this post were rambling..." Wizard


Link: The APOD I referred to