Big Dipper, Air Glow and Gravity Waves in Mourão Dark Sky


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UrsaMajorAirGlowMourao-net

In this picture captured in the great lake Alqueva, near the “Ermida de São Pedro” in Mourão, one of the regions belonging to the Dark Sky Alqueva Reserve, we cloud see the strong presence of Air Glow (Atmospheric Chemiluminescence) involving the Big Dipper constellation (Ursa Major) with the green light from oxygen atoms in a layer 90-100 km high. This emission layer is clearly visible from earth orbit. In the image, is also visible the gravity waves effect.  “These waves (internal gravity or buoyancy waves) abound in the stable density layering of the upper atmosphere. Their effects are visibly manifest in the curls of the stratosphere’s nacreous clouds, in the moving skein-like and billow patterns of the mesosphere’s noctilucent clouds and in the slowly shifting bands of the thermosphere’s airglow, as we could see in this picture and in the annotated version of this same image.

Canon 60Da – ISO 1600; 35mm lens at f/2; Exp. 15 secs. Mosaic of 2 images, taken in 15/06/2013 at 04:04 AM

Below is the annotated version of the image:

UrsaMajorAirGlowMourao-Label-net

 

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