Friday, February 1, 2008

Reflections on light pollution

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Images courtesy of NASA APOD, click image for more info
(Credit & Copyright M13: Noel Carboni, Digitized Sky Survey) and
(Credit M51: NASA, ESA, and The Hubble Heritage Team (STScI/AURA))

Light pollution is the bane of Astronomers. Professional astronomers often use instruments that operate outside of the visible spectrum. That's how telescopes like the DDO (see here to help save it) can still be effective even when located near a city. Recent studies suggest there are also biological effects on people, animals, and plants.

The ill-timed Earth Hour event will disappoint North Americans this year. However, you may remember the North Eastern Blackout of 2003.

That evening, I took my dog for a walk at the usual time. I took along a flashlight just in case. In good scouting fashion I was both prepared and didn't need to use it. Most of the people I met walking their dogs at the same time did not expect it to be so dark so soon! I told several families that I met that I would have a telescope on my front lawn. Upon my return, I set up my 8" non-computerized reflector scope on the front lawn. A couple of the families stopped by to look.

My first target, was the great globular cluster M-13 in Hercules. Without the city's interference, there was no effort searching for it. Next, I tried the Whirlpool Galaxy (M-51) beneath the handle of the big dipper in Canes Venatici (the hunting dogs). While I'd seen it before in larger scopes, this was a target that I'd never found myself. A few star hops and soon I found it near a small triangle of stars. While little more than small grey smudges in my scope, it was clearly visible. (Note: beautiful photos like the ones above require long exposure times as people don't actually see that well through telescopes).

Unfortunately, around about 10pm the full moon came up and ruined the party.

The next night with the lights back on, I returned. And even though I knew I was looking right at it, I couldn't see event a hint of the Whirlpool.

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