ApolloHoax.net
Apollo Discussions => The Reality of Apollo => Topic started by: onebigmonkey on October 22, 2014, 12:45:21 PM
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Having started looking at changes in shadow length in Apollo surface images I started to look at Apollo 12, and noticed a weird effect in the post-landing shots of the LM shadow.
Here's a close up of one of them http://www.lpi.usra.edu/resources/apollo/images/print/AS12/48/7026.jpg (http://www.lpi.usra.edu/resources/apollo/images/print/AS12/48/7026.jpg):
(http://i58.tinypic.com/2a0ardh.jpg)
In case you don't see it, it's as if there is a central region of truly dark shadow, with a lighter shadow around it.
My theory is that as the shadow is falling into a crater, light is being reflected by the crater walls into the shadow, causing it to be less dark.
Sound reasonable?
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Penumbra? Light diffusion in the window? Bleed on the film?
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Having started looking at changes in shadow length in Apollo surface images I started to look at Apollo 12, and noticed a weird effect in the post-landing shots of the LM shadow.
Here's a close up of one of them http://www.lpi.usra.edu/resources/apollo/images/print/AS12/48/7026.jpg (http://www.lpi.usra.edu/resources/apollo/images/print/AS12/48/7026.jpg):
(http://i58.tinypic.com/2a0ardh.jpg)
In case you don't see it, it's as if there is a central region of truly dark shadow, with a lighter shadow around it.
My theory is that as the shadow is falling into a crater, light is being reflected by the crater walls into the shadow, causing it to be less dark.
Sound reasonable?
Penumbra? Light diffusion in the window? Bleed on the film?
The Sun is not a point light source; it has an apparent diameter of about ½°, therefore, any shadow it casts is not sharp.
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I've outlined the dark bit to make it clearer:
(http://i57.tinypic.com/10hoo74.jpg)
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BTW, these pictures of LM shadows demonstrate very well the opposition effect that scatters a great deal of light onto the front of the LM to illuminate Aldrin in that picture of him descending the ladder.
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I've outlined the dark bit to make it clearer:
(http://i57.tinypic.com/10hoo74.jpg)
OK, I have enhanced the area by driving up the shadow contrast in Photoshop
(https://dl.dropboxusercontent.com/u/98915197/ApolloHoax/A12LMShadow1.jpg)
(https://dl.dropboxusercontent.com/u/98915197/ApolloHoax/A12LMShadow2.jpg)
Definitely see what you are talking about now. That has to be some kind of reflection into the shadow although I notice that the dark shadow still follows the general outline of the LM
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That seems to rule out penumbra. Light diffusion in the window seems to be at least speculatively still in play and an alternate cause.
Looking at the light blob near the bottom of the blow up, it seems to be the lunar surface. Any idea where that light came from.
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The blob in the bottom looks more like a lens flare - or perhaps some reflection in the window it was shot thorugh.
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I believe the 'blob' has been identified as from light shining through a gap between the ascent and descent modules.
I'm also beginning to wonder if the window, and film type, are combining to produce the effect. It doesn't seem to be present in B&W images taken of the LM shadow outside (although the angle of the photograph doesn't help there), and it doesn't seem to be present in the colour ones taken inside.
Later views in B&W of the LM shadow do not have as pronounced an effect.
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A lot of the B&W images from Apollo 12 have a "halo" effect. I had thought it was from dust on the lens but that is unlikely to be the cause here because they were taken before the first EVA.
Another possibility here is that the film anti-halation backing wasn't completely effective. This is a dark dye, visible on undeveloped film, placed on the non-emulsion side of the film to minimize light scattering. It dissolves during development.
I still wonder what was on the magazine they accidentally left on the surface. We'll never know; I'm sure the film disintegrated from thermal cycling long ago.
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Looking at the full image on the ALSJ, I see what looks like the out-of-focus shadow of the LPD (landing point designator, inscribed on the commander's window) on the right side of the image. The top (horizontal) part of the scale seems to project onto the right edge of the LM shadow.
This doesn't explain the entire effect, but it might explain the shape of it on the right side.
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I believe the 'blob' has been identified as from light shining through a gap between the ascent and descent modules.
That is what it looked like to me. I did not know there was a gap, so there is something new in the photo for me.
What window was it taken out of? A reconstruction of the camera position relative to the glass might give a clue.
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I believe the 'blob' has been identified as from light shining through a gap between the ascent and descent modules.
That is what it looked like to me. I did not know there was a gap, so there is something new in the photo for me.
Note that Apollo 12 landed yawed well to the right relative to the sun line; this partly explains the asymmetry of the shadow (e.g., the prominence of the RCS plume deflector on the right) and also the nature of the spots where the sun could shine through between the two stages. Of course the LM itself is rather asymmetric, with the ascent stage fuel tank jutting farther out to the -Y (CDR, left) side than the heavier oxidizer tank on the +Y (LMP, right) side.
What window was it taken out of? A reconstruction of the camera position relative to the glass might give a clue.
Pete Conrad's, i.e., the commander's window. The LPD is only present on that window, on the right side.
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I see what you are saying about the LPD. That answers the question.
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Having started looking at changes in shadow length in Apollo surface images
In your webpage you wonder how level the LM was on the surface. Each mission report gave the landed orientation in terms of pitch, roll and yaw.
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I believe the 'blob' has been identified as from light shining through a gap between the ascent and descent modules.
That is what it looked like to me. I did not know there was a gap, so there is something new in the photo for me.
Don't feel bad; you're not the only one who didn't know.
From the AS-17 Transcript:
117:23:44 Cernan: (To Parker) Hey, let me ask you. When I was behind the LM, I could look right into an area and see the bell of the ascent stage. I never realized that before, but I guess that's normal, huh?
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Well I wasn't really feeling bad about it, but now I do feel better. Funny how that works.
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II'm also beginning to wonder if the window, and film type, are combining to produce the effect.
Of course lets not forget scanning artifacts. Black blacks against non-black blacks have been know to give HBs the Hebejebes. Perhaps they could have a minor but easily reversed effect on the less credulous. :)
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Having started looking at changes in shadow length in Apollo surface images
In your webpage you wonder how level the LM was on the surface. Each mission report gave the landed orientation in terms of pitch, roll and yaw.
I did look for that and couldn't find it - I was surprised it wasn't there but obviously I was looking for the wrong information (slope in degrees rather than deviation from 0.
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I would advise a little caution here - this area is obviously way, way down in the blacks and once you get there posterising can occur very easily, especially if we are talking jpegs or indeed any 16-bit image where tiny variations in sensor readouts, even amplifier and readout designs, may give little jumps in the RGB numbers, especially at both the bottom and top of the brightness range.
Plus, as has been raised above, once the image is a second or third generation these effects could come from how it was scanned (some scanners have an awful lot of light spill) and processed, and all sorts of other effects may be involved eg film/backplate halation, effects from the reseau plate or other internal lens design/flare issues...
It would take a lot of careful research (none of which I have done) to look at exactly how that image got from the actual scene to that image file, and to identify all the things that might cause such an effect.. If it were possible, the best thing to do would be to take density measurements off the original film, and even then some of the stuff I listed above still may have caused it. I'd be extremely hesitant to offer any opinion on whether that is a real effect or not - I'd say it might be better to come at this from the opposite direction, namely an Nvidia-like analysis (http://www.apollohoax.net/forum/index.php?topic=648.0) on the scene to work out how the light falls on that shadow, ie identify every possible light source and check the terrain (is it a slightly more raised area, etc?) and see if there is a reason why it might be a real effect... Nvidia, wanna do another one? :D
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I did look for that and couldn't find it
Table 9-IV in the Apollo 11 Mission Report gives the PGNS surface Euler angles as yaw +13.2275 deg, pitch +4.44055 deg, roll +0.4614 deg. Not sure how yaw is defined.
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I did look for that and couldn't find it
Table 9-IV in the Apollo 11 Mission Report gives the PGNS surface Euler angles as yaw +13.2275 deg, pitch +4.44055 deg, roll +0.4614 deg. Not sure how yaw is defined.
I'm going with 'Slopey'.
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especially if we are talking jpegs or indeed any 16-bit image where tiny variations in sensor readouts, even amplifier and readout designs, may give little jumps in the RGB numbers, especially at both the bottom and top of the brightness range.
Especially jpeg. It's a lossy compression scheme that actually uses only 8 bits per primary color, and lossy compression on top of that. An amazing number of hoaxers and especially UFO believers have convinced themselves that JPEG artifacts really mean something.
all sorts of other effects may be involved eg film/backplate halation, effects from the reseau plate or other internal lens design/flare issues...
I hadn't thought of the reseau plate, but I could easily see how some light might scatter between the film emulsion and the surfaces of the plate unless (or even if) it is very carefully designed.
...Nvidia-like analysis...
CGI-like ray tracing analysis is proving surprisingly useful in various spacecraft problems. A few years ago, a Portuguese group used it with longwave IR to show that the so-called "Pioneer anomaly" was just due to the radiation pressure of heat from the RTGs reflecting off the spacecraft structure.