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Old Sep 8th 2014, 03:19 AM   #1
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sky gradient as seen from stratosphere?

Hi all.

OK so these were shot with the same camera with same settings. Both are supposedly at 28 km altitude in the stratosphere. Why does in the first image (NOT MINE) the sky appear pitch black while on the rest it is slowly fades to dark blue?

Any chance when the sun is in the horizon (evening time) the sky doesn't fade to black as much when looking from the stratosphere? That's the only thing I can think which is different between the first image and the last two.
Or do you think my own payload didn't reach even >15 km altitude?








more info about how these were shot: habhub.org
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Old Sep 8th 2014, 04:57 AM   #2
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There are four images in your post, not two. Which two of the four are you comparing? I will assume you mean the first image (Santa's sleigh) against the second. If these were indeed shot with the same camera, lens, f-stop and shutter speed, and also assuming no photoshopping, it seems to me that the first image was taken at a higher altitude, and hence the sky is darker. The cloud deck appears much lower in the first photo, making it appear to be at a significantly higher altitude.
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Old Sep 8th 2014, 12:46 PM   #3
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Thanks. So you don't think its because of getting more Rayleigh scattering of the blue light from the sun shining up toward you (last 3 images) through the atmosphere (i.e. sun closest to the horizon) than from the sun shining down toward you from above (first image)?
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Old Sep 8th 2014, 01:42 PM   #4
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I can think of the following possible causes:

1. Less humidity, or dust in the air in the Santa picture.
2. As already noted - the Santa pic appears to be made at a much higher altitude.
2. If the sun is higher in the sky in the Santa pic, that would mean the cloud tops should be much brighter. But they're not, which tells me that the camera lens was stopped down in that pic (or quicker shutter speed). Consequently the sky appears darkened in the photo.
3. Photoshop - it's easy to darken out the sky to make a more dramatic effect. Since everyone knows Santa flies at night, darkening the sky would seem a natural enhancement for someone to make.
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