Light Pollution - Birmingham's Night Sky
Birmingham is the UK's second largest city, with an immediate population of over one million, and a catchment area of some 7 million people. Observing from this massive metropolitan area can be difficult, with it being impossible to escape the localised and general light pollution present. Even driving into the country doesn't help, as the glows from the massive industrial area of the Midlands are always present on the horizon.
The images shown here reveal just how bad light pollution in Birmingham and the surrounding area is, and the problems experienced with localised light pollution caused by street and security lighting.
This is Birmingham at night - or at least the part which is 3 miles east of my home. The city centre, which lies just 5 miles to the south of my location, produces far more light pollution than this photograph shows.
A view of Birmingham from the South of the city. This photograph was taken some 12 miles distant at the Clent Hills, a "darkish" site where I have made many Meteor watches over the years. This short exposure was made under very transparent skies, with no haze present!
This is the view of the street-lighting in my road, and directly outside my house. These Sodium lights replaced old fashioned Mercury lamps in 2003. The road is now well illuminated after dark- as is the night sky!
In 2014 Birmingham City Council have been replacing these streetlights with new LED lights - my road is still waiting! These new lights from surrounding roads have had the effect of brightening the background sky, thus making the light pollution much worse. Each light has 48 LED's situated in a convex housing, so that light is transferred down and slightly sideways. These lights refelect more light upwards than previous street lighting.
This image taken from my back garden shows the problem I have with localised light pollution.
Each light is on a passive IR sensor, and remain on for several minutes when activated. The two lights in the foreground present the biggest problem, as they shine directly into my garden. Both remain on for 5 minutes each time they become activated, whereas the others stay on for around three minutes. Although my observatory protects me to a certain degree from the direct glare of these lights, the sky becomes saturated with stray light whenever they are triggered. This is the view looking North. Houses to the South are similarly equipped, as are the houses to the East. To the West is street lighting as shown in the images above.
The best way to illustrate the problems that light pollution cause to the visual observer is through photographs of the night sky. These two images were taken in September 2005. Top we see Mars near to the Pleiades, whilst bottom is Orion rising in the South Eastern sky.
Both images were taken with a digital camera set at ISO 200, with 10 seconds unguided exposure. The sky was very transparent on the night, with no haze present at all. You can just make out the tree being illuminated from a security light on the left. The orange sky is from general light pollution of the area.