Dark at night: What a concept

How dark is it in your lake after the sun goes down? Is it truly dark so that the sky blazes with stars? Or do lights on the ends of piers, or lights leading up people’s stairs, obscure the lights in the sky?

If you’re like most of us, the latter is true. I remember years ago, after four years of attending college in the middle of a city, I drove to a cabin in Michigan’s Upper Peninsula where my family was taking a week’s vacation. This cabin had no electricity; interior light came from kerosene and gas-mantle lamps. The lake was also rather isolated and the cabins on its shore widely spaced.

On arriving, well after sunset, I pushed out onto the lake in a rowboat. It must have been a new moon night, because my eyes immediately were drawn upward – I had never seen (or couldn’t remember seeing) stars so bright and so numerous. I appreciated for the first time the spectacle of the Milky Way; I easily picked out favorite constellations. I gazed at the sky for a long time. It was incredibly peaceful; also awe-inspiring.

Such views are becoming rare these days because we insist on lighting the places where we live, even we don't really need the light. A long-time friend, Dan Heim, from near Phoenix, Arizona, writes now and then about this problem on his astronomy blog, Sky Lights (http://heimhenge.com/skylights/). It’s called light pollution.

Of course, light pollution is most acute in cities, but even here in Wisconsin’s lake country, it’s very much in evidence, and not just within the orbit of the little towns. On a lake such as ours – Birch Lake at Harshaw, Wisconsin – it takes just few bright lights along the shoreline to create a glare that impedes the view of the night sky. As it happens, just a few people leave pier lights or yard lights on all night – for what reason I have no clue. If they were to turn them off, we would have spectacular stargazing, because we are 10 miles from the nearest town and have no streetlights nearby.

One thing I am considering on our lake is to try organizing a monthly “lights out” night, where all the lights go off for an hour or two after, say, 10 p.m. I haven’t tried this yet, because we’re pretty new to the lake and I don’t want to be seen as an intruder trying to tell long-time residents how to run their lives. But as I get to know more people here, a may give it a shot.

Have you tried any such thing on your lake? Let me know what you’ve attempted and how well it has worked. And in the meantime, if you are at all interested in astronomy, I highly recommend subscribing to my friend Dan’s blog.