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DSCOVR |
Jan 6 2006, 08:55 PM
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#151
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
ADMIN NOTE: Please note that this topic was unavoidably poltical before the 'No Politics' rule. Please restrict future comments to the mission/spacecraft/news updates etc.
WHAT'S NEW Robert L. Park Friday, 6 Jan 06 Washington, DC DEEP SPACE CLIMATE OBSERVATORY KILLED. http://bobpark.physics.umd.edu/index.html -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Oct 27 2023, 07:11 PM
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#152
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
That image is the "enhanced" version. The "natural" version doesn't look quite as bad:
https://epic.gsfc.nasa.gov/archive/natural/...31014165817.png Looking at the pixel values the blue channel drops to precisely zero in the penumbra, giving the brown hue. I suspect somewhere in the processing (combining the raw channels into the colour version) they've clipped the low end of the blue (and green) channels. Their processing probably wasn't designed for such dark levels since the Earth is normally (almost) fully sunlit from L1! Actually limb darkening of the sun is wavelength dependent, with shorter wavelengths more attenuated than long near the rim. So around annularity the illumination should actually be shifted to the red. But most of the visible penumbra is still lit by some of the central area of the sun's disk, so I wouldn't expect a noticable effect in these images. But near the narrow path of annularity the illumination should be shifted somewhat to the red. It would be interesting to quantify that. Sometimes people report a change in the "character" of the light near annularity - maybe the colour shift contributes to that. I didn't notice a colour shift at either the 2023 or the 2012 annular eclipses, just the dimming. Of course the eye would adapt to such a slow colour shift. |
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