2 replies to this topic

[Tony Flanders]

One of the dire facts about light pollution is that darkness is so fragile. All it takes to ruin a dark place is one light.

 

To take one example from personal experience, one of my favorite spots to observe when I'm living in my city apartment in Cambridge, MA, is a public park called Robbins Farm in Arlington, MA. It's just 7 miles from downtown Boston, so the skyglow is huge, but within its suburban context Robbins Farm is delightfully dark -- usually.

 

There are perhaps three or four dozen houses fronting the park, and the lights shining out their windows are readily visible, but I don't find them particularly annoying. But there's one house with a bright, unshielded porch light, and when that light is on I can't look in that direction without getting blinded. So I lose a whole sector of sky.

 

At locations far from population centers the situation is far more dramatic. It takes a fair amount of light to ruin a suburban park that's already bright from skyglow alone. It takes nothing but a bright flashlight to ruin a pristine location.

[rowdy388]

I put my new shed in a location that blocks a neighbor's unshielded porch light from my observation deck. The light is about half a mile away, but you're right that distance makes very little difference. Saves me from having to put up light blocking panels. Trees can block a lot of light, but they block out a lot of sky at the same time. 

[treadmarks]

Well that is disheartening, and not just because Robbins Farm is a former observing site of mine when I lived in that area. But I think most of us know it to be true - no urban backyard is safe. I recently moved to a new house about 30 miles north of Arlington and quickly learned about my neighbors' poorly set up floodlights.

 

Personally I have adjusted to the realities of urban astronomy by picking my targets accordingly: planets, Moon, Sun, double stars, planetary nebulae, and certain star clusters. I don't trouble with dark site trips anymore unless I specifically want to see galaxies, nebulae, or the Milky Way. In a way it is liberating because I don't worry about night vision, I just get to it.

 

I'd say this also points to the importance of club dark site or IDA-sponsored stargazing locations which have some control over lighting. Even then, I've found the nearby club location gets beamed surprisingly often by vehicle headlights.

Edited by treadmarks, 25 January 2023 - 10:00 PM.