There are specialized tools available to measure sky brightness from a very localized area such as a sky quality meter. For example, a Class 1 Bortle sky means that one can observe M33 ( Triangulum Galaxy) as a direct-vision naked eye object. The Bortle scale uses astronomical observations to measure the amount of light pollution for a given location. This is an appropriate description of my night sky quality, as I live in the center of a medium-sized city (Population of 130,000). For example, my Class 8 backyard sky has the title of “City Sky”. Unfortunately for many backyard astrophotographers, their primary imaging location is much farther down the Bortle scale then they would like. There are nine levels to the Bortle scale with Class 9 being the most extreme amount of light pollution. The Bortle scale is a way of measuring the quality (brightness) of the night sky for a particular location. Aside from the opportunity to collect astrophotography images with improved signal, I am also able to see many more stars in the night sky from my backyard visually. I later moved from a house under Bortle Class 8 skies to a Class 6, which made a big difference in the amount of light pollution I observe from home. As discouraging as these readings may sound, it doesn’t mean that you can’t enjoy astronomy (and astrophotography) in conditions like this.

The sky quality at my home is a class 8 on the Bortle scale, which is the second brightest sky possible. I have personally battled with light pollution in my backyard when taking deep sky astrophotography images.

There are a number of ways to measure how much light pollution affects a given location (SQM, NELM), but my personal favorite way to gauge the quality of a location is the Bortle scale. These colors represent the amount of artificial light in the area, and how bright the night sky will look.Ī light pollution map showing the location of my backyard One of the easiest ways to identify the brightness of your night sky is to use the Bortle scale.Ī light pollution map will show that a large city radiates white to red from the center, and rural areas will appear green to blue. You may have noticed that amateur astronomers and astrophotographers will often describe their sky quality reading when posting pictures or discussing observations.

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