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Venera Images, VENERA 13 fully calibrated image
hendric
post Sep 13 2006, 10:06 PM
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AndyG

Here you go. smile.gif


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AndyG
post Sep 14 2006, 08:55 AM
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QUOTE (hendric @ Sep 13 2006, 11:06 PM) *
AndyG

Here you go. smile.gif

Toastie! Thanks - that's more like it. Now if only it had had a video camera on it!

Andy
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ngunn
post Sep 14 2006, 10:51 AM
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QUOTE (hendric @ Sep 13 2006, 11:06 PM) *
AndyG

Here you go. smile.gif


That's just brilliant, though I would expect a more orangey-brown colour for the sky and the distant hazy hills.
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Guest_DonPMitchell_*
post Sep 14 2006, 03:28 PM
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QUOTE (hendric @ Sep 13 2006, 03:06 PM) *
AndyG

Here you go. smile.gif


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I'm not sure I understand. What is the coloration for?
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hendric
post Sep 14 2006, 04:38 PM
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AndyG was complaining that the "Real Venusian Environment" didn't come through, so I added a little bit of red to the picture to give it that "this is hot as an oven" look to it.


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Space Enthusiast Richard Hendricks
--
"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
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Guest_DonPMitchell_*
post Sep 14 2006, 08:57 PM
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QUOTE (hendric @ Sep 14 2006, 09:38 AM) *
AndyG was complaining that the "Real Venusian Environment" didn't come through, so I added a little bit of red to the picture to give it that "this is hot as an oven" look to it.


Ah! :-)

Of course the sky of Venus is actually bright orange. Everything is bathed in orange light, from a uniform hemispherical source. The cloud layer, far above, is not visible from the surface. Strong rayleigh scattering causes the terrain at a distance to be lost in a greenish-yellow haze that eventually merges with the orange color of the sky.

At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.

Colors from the Venera probes have never been rigorously calibrated. First of all, the radiometric response of the camera that was used before is incorrect. The spectral response of the color filtes is known, but not the relative gain correction. I have talked with Gektin about this (the camera designer), and he is searching for some data that will permit absolute calibration of the color. Namely, the spectrum of a colored calibration lamp, which was imaged during the video retrace interval.

The Russians knew what to do in theory. They realized you have to solve an integral equation to recover color from the spectral responses of sensors. Bravo for them, because I don't think any American space photos have ever been processed with that sophistication. But having written that in their paper, the Russians were unable to perform the calibration, because they lacked the necessary computers.
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ljk4-1
post Sep 15 2006, 01:33 AM
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QUOTE (DonPMitchell @ Sep 14 2006, 04:57 PM) *
At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.


I recall that all the drop probes from the Pioneer Venus Multiprobe mission reported
an increase in infrared glow before those sensors were overwhelmed. Any ideas on
what it might have been?


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not thus harden and make coarse. A hard, sensible man whom we liken to a rock is
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no sympathy, I go to commune with the rocks, whose hearts are comparatively soft."

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ngunn
post Sep 15 2006, 08:45 AM
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QUOTE (DonPMitchell @ Sep 14 2006, 09:57 PM) *
Ah! :-)

Of course the sky of Venus is actually bright orange. Everything is bathed in orange light, from a uniform hemispherical source. The cloud layer, far above, is not visible from the surface. Strong rayleigh scattering causes the terrain at a distance to be lost in a greenish-yellow haze that eventually merges with the orange color of the sky.

At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.


You have done so much work already to make the place look 'real' and obviously have your own mental picture of the true colouration. Why not share it with us? - perhaps day and night versions, assuming the ground glow is just visible?
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tty
post Sep 15 2006, 10:59 AM
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QUOTE (DonPMitchell @ Sep 14 2006, 10:57 PM) *
The Russians knew what to do in theory. They realized you have to solve an integral equation to recover color from the spectral responses of sensors. Bravo for them, because I don't think any American space photos have ever been processed with that sophistication. But having written that in their paper, the Russians were unable to perform the calibration, because they lacked the necessary computers.



How very typical both of Russia and the US. As somebody said "as long as it can bew done with paper and pencil the russians are unbeatable".

tty
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vikingmars
post Sep 24 2010, 08:39 AM
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huh.gif A new work on the Venera 9 - 14 images was presented 2 days ago by well known Venus scientist Dr Ksanfomality at the European Planetary Science Congress 2010:
http://meetingorganizer.copernicus.org/EPS...PSC2010-273.pdf
Unfortunately, no more details yet...
BUT, having myself analysed all the Venera data available, I don't think there is much more to be seen : all features on the horizons were enhanced and the Venusian sky shown already in this UMSF Forum topic.
_______________________________

[quote from the abstract with no images published] :
"In 1970-80 the VENERA 9, 10, 13 and14 probes imaged the surface of Venus at landing
sites. These TV photos have been published by many scientific editions, either original or
processed. Since the visits of the pioneering VENERA landers, there have been steady
efforts to achieve a better processing of the original images for following analysis. This
paper is devoted to the description of few segments of re-processed images at their right
and left hand sides, demonstrating features not noticed earlier (or ignored due to their
distortion). Using this re-processing, interesting images that included both horizon and
sky of Venus were produced. In the new images next mount chains or valley slopes
appeared at the horizon line
."
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JohnVV
post Sep 24 2010, 08:26 PM
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this is an old thread . has the color issue been better solved since '06
As i recall , when i did my map and colorized the radar data , there were some images redone to get the color strip on the lander "closer" to there colors .
But did not take into account the effects from the pressure . and that the rocks would most likely have a slight bluish tint ( if they were on earth)
In the end I gave up and just used an artistic color
[attachment=22593:venus_VT...an_Vliet.jpg]
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sariondil
post Oct 2 2010, 12:37 PM
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A collection of surface panoramas: 180 for Venera 9 and 10, 360 for Venera 13 and 14. Reprojections are according to various suggestions on this forum. Horizon topography is probably not real, but due to inaccuracies of the reprojections (which are not strictly geometric anyway).
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Phil Stooke
post Oct 6 2010, 06:06 PM
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Nice job, Sariodil. I'm not sure I agree with your connections between features near the horizon for Venera 13, but it looks good anyway. I have often thought of trying to map these landing sites, so just playing with your images I came up with these for Veneras 13 and 14. Very preliminary, but it gives an idea of what might be done eventually. The orientations of these images (where north is, in other words) is unknown.

Phil

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Explorer1
post Oct 6 2010, 07:35 PM
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All these re-projections and reprocessing you've accomplished here just whets my appetite for new missions. The Venusian surface has been neglected for far too long...
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sariondil
post Oct 8 2010, 07:44 PM
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Im not sure about the Venera 13 horizon either. When the horizon in the Camera I image came out concave in the reprojection, I thought it could be a valley floor at a lower elevation than the hills in the adjoining part of the Camera II image. On second thought, however, smooth concave valley floors are probably not what you would expect on a planet with so little erosion.
But if erosion has no part in shaping the surface, could the gaps in the hills on the horizon be the surface expression of faults? If so, one could align them with the fault azimuths on Magellan images of the landing site to narrow down the possible orientation of the panorama.
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