The Light Pollution Problem
Bortle Scale sky comparison
ESO/P. Horálek, M. Wallner - This media was produced by the European Southern Observatory (ESO), CC BY 4.0
The New World Atlas of Artificial Night Sky Brightness found “that about 83% of the world’s population and more than 99% of the U.S. and European populations live under light-polluted skies.” And In his book, The End of Night, Paul Bogard writes, “people living in the continental United States and western Europe — no longer experience a truly dark night, a night untouched by artificial electric light.” Light from our man-made artificial light sources cast an unwelcome glow across the sky and into our private spaces. This is what we call light pollution. DarkSky International describes light pollution as “the human-made alteration of outdoor light levels from those occurring naturally”, including sky glow, glare, light trespass, and clutter.
So what can we do to help mitigate some of these sources of light polllution to lessen the effect it plays on our ability to enjoy the night sky? For our purposes we shall think of light pollution emitting from two types of sources, direct and indirect. An example of a direct source would be your neighbor’s lights, and an indirect source would be something more like sky glow.
For those direct sources, the first thing we could do is talk to our neighbors to try and persuade them to put their outdoor lights on a motion sensor or turn them off altogether. If that doesn’t work, you could build a light barrier to block the intruding light source. For example my own neighbor refuses to turn out the lights at night so I use a barrier to block the majority of bright light. In terms of locating your observatory, you can use the observatory building itself to block that unwanted light. For example if your intent is to build a roll-off roof observatory, you can orient the open position of the roof to block the light, but this depends on your zoning. you could also plant coniferous trees as they don’t loose their needles and tend to produce less transpiration than deciduous trees to block the trespassing light sources.
These are all relatively easy solutions to mitigate those direct sources of light, but now what about the indirect ones? One of the easiest ways to deal with indirect sources is to use your observatory building to block the sky glow at the lower altitudes along the horizon. This can be highly effective if done the right way. Another solution is to locate your observatory in an area that is dark like Bortle 1 or 2 . While this solution take more effort, research, and money, it is the best all around solution. Luckily, our STELLARSPACES™ S.T.A.R. STUDY™ can help you with this research. Consider downloading our STELLARSPACES™ Planning Pack to learn more also visit the websites below: