What does Bortle 5 mean in your Blog Title?

So what in the world is "Bortle 5" in your title exactly mean?  

An American amateur astronomer by the name of John E. Bortle created this useful scale of the quality (brightness) of the night sky.  His work was published in the February 2001 edition of "Sky and Telescope."

The nine-point scale goes something like this: Bortle 1 :  Excellent Dark Sky Site, Bortle 2:  Truly a dark sky site , Bortle 3:  Rural Sky Site, Bortle 4: Bright rural sky,  Bortle 5:  Suburban sky, Bortle 6: Bright Suburban sky, Bortle 7: Suburban / Urban transition, Bortle 8: City Sky, Bortle 9 : Inner City Sky

What makes the sky more light-polluted are the amount of lights in the area, such as streetlights, floodlights, security lights, advertising, and building lights.   

Light pollution hides the beauty of the Milky Way from 80% of Americans.  

I am fortunate to live in Bortle 5 skies outside of Atlanta.  However with more growth and development in our area, the light-pollution is bound to increase.     

As an Astrophotographer, there are different methods I use to help cut down on light-pollution in my images.   First, I use an OPTOLONG 2" L-Pro Deep-Sky Light Pollution Filter in my telescope imaging train (just prior to the camera).  

OPTOLONG describes this filter use for "suppressing light pollution from artificial light and enables astrophotos of broadband emission objects such as galaxies, reflection nebulae and globular clusters."

The second method of dealing with light pollution in my photos in in the post photo-processing.    My final image after stacking all my light, darks, biases, and flat frames is a green-light polluted picture.    I use several tools to eliminate the light pollution and pull out the beauty of the my target through Adobe Photoshop using add-ons such as Gradient Xterminator, HVLG (Hasta La Vista Green), and ProDigital Software Astronomy Tools.

The pictures below are BEFORE AND AFTER examples on my recent target M106, a spiral galaxy located 24 million light-years from Earth in the constellation Canes Venatici.   You can see a huge difference between the two images.

 

I hope this helps you understand the Bortle scale a little more.   If you want to see what Bortle skies you live under, check out this light pollution map here. 

Light Pollution Map

Until next time, clear skies!

What are your thoughts?  What kind of light pollution or Bortle skies do you have in your location?  Comment below!

Enjoy learning more about Astronomy and Astrophotography?   Come explore with me with my newsletters and YouTube channel.

For my Astrophotography at Bortle 5 website, visit
https://astrophotography-at-bortle-5-omsmyt.mailerpage.io/

Visit my YouTube channel for more astrophotography
https://www.youtube.com/@astrobortle5

For the latest Blogger updates, subscribe to my Newsletter
https://tinyurl.com/2arry74k