Astronomy

Choosing an Observing Site for Urban Stargazing



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Stargazing in the urban environment is not always the easiest thing to do.  Light pollution can wipe out all but the brightest objects in the heavens, while manoeuvring your telescope to the ideal viewing area outside the city, can prove a bit off putting to the keenest stargazer.  Especially if it takes an hour drive to get to the best spot.

Surprisingly, the biggest problem with finding an observing site for urban stargazing isn’t so much the light pollution caused by all the streetlights and floodlights around us.  This light pollution does cut down on the stars and constellations we can see, but with a good quality telescope, lenses, and using a light pollution filter, you can still see a tremendous amount of astronomical objects.  You'll never see as much as you would in a light pollution free country area, but you will still get some good views of the sky.

Nor is a large aperture telescope more prone to the effect of light pollution than a smaller aperture telescope.  It is the heat currents and atmospheric conditions which cause problems, not the light pollution.  This is why early morning stargazing is more productive when you are in an urban environment.  The atmosphere is usually a bit more stable, and the light pollution is less.

It is the localised light pollution that is the headache for urban stargazers.  This is caused by badly placed streetlights, your neighbour's security light, or you own house or patio lights.  If you are fortunate to have a back garden to view from, you can considerably increase the objects available for viewing by reducing the localised pollution in a number of ways.

Reducing the localised pollution can be done by something as simple as switching off your own house lights when viewing the stars.  If the localised lighting is out of your control, consider building yourself a temporary observatory.  Even hanging a blanket over a clothesline to block out the source of light will help.  Using rubber eyecups on your lenses will also help to reduce the light affecting your viewing, by stopping light leaking through the top of the lens.

If you are transporting your telescope to a dark area to view the sky, such as a local park or darkened car park, make sure the area is safe.  Check out the area during the day, as ensuring your own safety is more important than stargazing.   Also check whether you can carry your telescope to the area without problems.

The night sky will be noticeably freer of light pollution in an urban area, if you leave your viewing until early morning.  The stars, constellations, and planets are also brighter, the nearer they are to the North Star, so concentrate on the astronomical objects which are highest in the sky.  Stargazing in an urban area will always have its problems, but they can all be overcome to some degree.

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