Sorry, the server that was hosting the image of my post above failed. I made a mirror copy to a different server, I re-post my original message here but with new links for the images :
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I was wondering what conditions should be met to have the "darkest" sky ...
Well, obviously there should be no Moon light. The Milky Way and zodiacal
light should not be visible neither, and the image should be taken at a
place with no light pollution. If these are correct criteriae, the following
picture must be very close to what the "darkest" sky could be.
The following fisheye image was taken at new Moon (No Moon light), middle of
the night (minimum zodiacal light effect), in the Atacama desert close to
Paranal observatory (no light pollution). The chosen place for this picture
has the particularity to be located at a latitude which value is close to
the declination of the galactic southern pole. The picture was therefore
also taken when the galactic pole passes at zenith, ensuring that there is
no Milky Way up in the sky. When all these conditions are met, the very
faint Gegenschein becomes visible.
"The darkest sky ?"
"Milky Way all around the horizon line"
The "by product" of this image is that the Milky Way plane lies all around
the horizon as visible in the following 360 degrees panoramic view.
Annotated version :
If you want to see the very large zoomable images with annotations you should go there :
http://www.eso.org/~sguisard/Pagim/darkest_sky.html
Stephane
PS: The first version this kind of image with the Milky Way all around the horizon line was taken a few years ago :
http://www.astrosurf.com/sguisard/Anim- ... 0x600.html
Sorry, the server that was hosting the image of my post above failed. I made a mirror copy to a different server, I re-post my original message here but with new links for the images :
***************************************************************************************
I was wondering what conditions should be met to have the "darkest" sky ...
Well, obviously there should be no Moon light. The Milky Way and zodiacal
light should not be visible neither, and the image should be taken at a
place with no light pollution. If these are correct criteriae, the following
picture must be very close to what the "darkest" sky could be.
The following fisheye image was taken at new Moon (No Moon light), middle of
the night (minimum zodiacal light effect), in the Atacama desert close to
Paranal observatory (no light pollution). The chosen place for this picture
has the particularity to be located at a latitude which value is close to
the declination of the galactic southern pole. The picture was therefore
also taken when the galactic pole passes at zenith, ensuring that there is
no Milky Way up in the sky. When all these conditions are met, the very
faint Gegenschein becomes visible.
"The darkest sky ?"
[img2]http://www.eso.org/~sguisard/Pagim/SGU-darkest_sky-Gegenschein-IMG_2207-1200x1200-cp10.jpg[/img2]
"Milky Way all around the horizon line"
The "by product" of this image is that the Milky Way plane lies all around
the horizon as visible in the following 360 degrees panoramic view.
[img2]http://www.eso.org/~sguisard/Pagim/SGU-Milky_Way_all_around_horizon-pano-IMG_2207-2500x500-cp10.jpg[/img2]
Annotated version :
[img2]http://www.eso.org/~sguisard/Pagim/SGU-Milky_Way_all_around_horizon-pano-IMG_2207-names-2500x500-cp10.jpg[/img2]
If you want to see the very large zoomable images with annotations you should go there :
http://www.eso.org/~sguisard/Pagim/darkest_sky.html
Stephane
PS: The first version this kind of image with the Milky Way all around the horizon line was taken a few years ago :
http://www.astrosurf.com/sguisard/Anim-astro/Paranal-Gegenshein/SGU-Paranal-Gegenshein-S-900x600.html