Observing the night sky in an urban area makes stargazing more difficult but not impossible. An urban stargazer is never going to see the same things as an observer situated in a rural area but careful thought in selecting a site can make a difference.
– Why is urban stargazing more difficult? –
The most significant factor that lessens the enjoyment of stargazing in urban areas is that of light pollution. Serious light pollution from street lights, cars, neon signs and domestic internal and external lighting manifests as a sickly orange glow that almost appears to hover over large urban areas. Astronomers actually refer to this as sky glow.
Line of sight pollution refers to something that is directly shining on the observer such as a neighbor’s exterior light. It is generally localized and more easily escaped from than sky glow.
Another factor that inhibits the urban stargazer is that of obstacles, such as buildings, obscuring large parts of the sky.
– Choosing a site –
Traveling even for a few minutes away from the center of an urban area can make enough difference to make the effort worthwhile. In all but the very largest of cities a 15 minute journey may be all it takes to decrease light pollution effects significantly.
Get as elevated as possible. This will help to raise yourself above all but the highest obstructions and give a wider view of the night sky.
Wherever possible, block line of sight light pollution. Even just turning your back on a localized light source will make all the difference. Use fencing, boards and even buildings to block out light in this way. Some astronomers have their own portable boarding that they will use to cut out line of sight problems.
Observe the moon phases. A full moon will wash out the night sky even in areas with no other light pollution. The best moon phases for stargazing are new moon, when the moon’s proximity to the sun means it isn’t visible, or the third quarter phase which is where the moon has passed full and is starting to wane. In the third quarter the moon is late in rising so the skies will be moon free until just after midnight.
Position yourself south of light pollution sources wherever possible. The southern sky is where most of the interesting stuff takes place, from a night sky point of view, so heading south of an urban area will position the main light pollution behind you.
Use binoculars. Telescopes are of course even better but owning a pair of binoculars is far more likely in most cases than being a telescope owner. Even the weakest binoculars will offer you far greater stargazing opportunities in an urban area than the naked eye. They also work well to cut out line of sight light pollution.
Stargaze later at night. It is an interesting fact that much urban light pollution reduces in the early hours of the morning. Generally speaking there are less cars on the road, domestic households have gone to bed and switched off many light sources and even business lighting is reduced after midnight in many cases.
There is no doubt that as an urban stargazer you will face greater challenges than some-one observing from a rural area but opportunities are still possible.
