Urban stargazing has always been a bit of a compromise, due to the city light pollution wiping out the stars in the night sky. This doesn’t mean that you can’t enjoy observing astronomical objects from within the boundaries of a city environment.
There are two forms of light pollution the urban stargazer has to put up with. There is the general light pollution of the thousands of streetlights, the shopping mall lights and the sports ground floodlights, along with a host of other light polluters. The second form of light pollution is what can be called localised light pollution, and is the light from nearby streetlights, household, and security lights.
Although the urban light pollution will wipe out a lot of the deep space objects, observing the night sky is still possible with good results. Sadly, unless you can transport your telescope to a darker viewing area, you will have to live with the effect of these lights. Localised light pollution is another matter, and with a bit of forethought, you can avoid these close-by lights. The difference to your viewing just by positioning your telescope away from next door’s patio light, or switching off your own house lights is quite surprising. Creating your own temporary observatory out of a cloth screen or even a blanket over a clothesline may just help reduce localised light pollution.
When choosing a telescope for urban stargazing, the aperture isn’t the problem. A large aperture telescope will perform as well as a small aperture telescope, with the light pollution making very little impact of viewing performance. So don’t skimp on the telescope you want just because you are worried about light pollution.
What an urban stargaze does need to consider about their telescope, is whether the telescope is too big to be manoeuvred to its viewing position or not. After all, if you have to carry your large telescope down several flights of steps to where you want to use it, you will soon find excuses to leave it at home.
You can purchase filters, which claim to reduce light pollution, and they do seem to help in polluted areas. They won’t make an object brighter, but the filter will darken the background a little more, causing the object you’re observing to appear brighter.
You should always buy the best lenses you can afford, as the faults in cheap lenses can make stargazing a waste of time. It’s a good idea to get lenses fitted with eyecups. An eyecup will go a long way to help cut down light getting in around the eyepiece.
Successful viewing of the stars in an urban environment can also be greatly increased if you plan when you do your viewing carefully. Objects in the urban night sky can be seen better, the higher the object is. So astronomical objects nearer the North Star will be less impacted by light pollution when compared to object near the horizon. The level of light pollution can also be seen to drop off as the night wears on, with the early hours of the morning giving the best opportunity to maximise your urban stargazing.
So find an area to view that has little localised light pollution. Choose the telescope that suits your needs, but can be easily moved to the viewing area. Concentrate on viewing objects high in the night sky, and consider viewing during the early hours of the morning when light pollution is reduced.
