I captured this photo of Luna’s Milky Way last April during a trip to the Big Bend National Park with some of my photography friends. I posted another photo of Luna’s Jacal with the Milky Way last April. I also posted a story of how to use the Planning Tools to aid in capturing these type of photos. Night photography is one of the main reasons I enjoy going to the Park. The light pollution in the park is near zero. You can actually see the Milky Way Galaxy with your naked eye.
Light pollution is measured using the Bortle Scale. This is a nine-level scale that measures the night sky brightness. The scale was created by John E. Bortle and published in 2001 to help amateur astronomers evaluate the darkness of an observation site. Class 1 is for the darkest sites available on Earth while Class 9 is for inner-city skies. The scale gives some criteria as to what celestial objects you can see given that classification. For example, in a Class 1 sky (the darkest) you are able to see many faint constellations as well as shadows cast by other regions of the Milky Way. A Class 9 sky is brightly lit by city lights and the only brightly visible objects are the moon, planets and bright constellations.
If you live in Texas, the Texas Parks & Wildlife Department publishes the Bortle Ratings for each of the parks. You can access their page by clicking here. I am sure that other states and countries publish the scales for their parks. If they don’t, then you can use the Blue Marble Navigator website to determine the light pollution for a certain area.
This image was taken with my Canon EOS 5D Mark III using my Sigma 14mm f/2.8 Lens. The camera was set on Manual mode with the aperture set at f/2.8, shutter speed at 15 seconds and the ISO set at 5000. The inside of Luna’s Jacal was lit with my head lamp. I simply turned it on and left it in the opening. The mountain was lit by a car that was traveling down the dirt road. This is a single image processed in Lightroom and Photoshop.
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