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Post by LunarOrbit on Jun 27, 2007 13:11:15 GMT -4
It's my understanding that the disturbance is not visible in the light spectrum we see in, the Clementine probe used special filters to see it.
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furi
Mars
The Secret is to keep banging those rocks together.
Posts: 260
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Post by furi on Jun 27, 2007 13:29:42 GMT -4
I suppose it would also depend on what the frequency the photograph was taken in, I believe the Clementine optics can process IR through to UV, if so you might be looking at a representation of IR reflection. if so the disturbance would not have been captured on film designed for VL *edit after I found the sort of images I wanted to link to* tinyurl.com/23sxznthis is a picture from shifted UV, the different light spectrum allows for a vastly different image to what the Human eye can see the following 2 are both taken in x-rays tinyurl.com/2aqvt8tinyurl.com/257pncand finally a Filtered Visible Light pic (poss He) www.britannica.com/ebi/art-67533
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Post by JayUtah on Jun 27, 2007 13:34:23 GMT -4
Why didn't these unsubtle rover tracks show up?
Because they're too small. The plume effects seen in the Clementine image were uniformly evident over a very broad range of the lunar surface, large enough to be visible from lunar orbit.
You might be confused by what I mean when I say "subtle." You can interpret that two ways. The footprints and rover tracks are evident to the naked eye at close range because they have distinct edges and because they dig up the darker layers of the lunar surface several centimeters below the lighter top layer. They wouldn't be visible from orbit because they're too small. Even though the color might be very different, the camera is just too far away.
The plume effects that Clementine saw are subtle in the sense that the difference in color is very, very faint. In fact, it isn't visible to the naked eye. The Clementine image was formed by combining pictures of the same area taken with different filters over the camera lens. This is a technique commonly used in orbital remote-sensing because we know we can identify certain features or characteristics by how they show up when those different filtered images are combined in a computer using sophisticated image-processing programs -- sort of like complicated Photoshop filters.
The combination of filtered camera images and computer image processing makes visible some properties that simply aren't visible to the eye, but are important nonetheless. In this case, the Clementine researchers programmed the computer to look for the specific combination of optical properties that indicate recently disturbed lunar soil, even if the disturbance was very slight. That helps them look for recent impact craters. Incidentally they noticed the recent effects of the LM exhaust, which are very subtle in terms of color (in fact, it's not even "color" in the commonly-understood sense) but very large in area.
So to sum up, the footprints are distinct in color but very small. The plume effect is very large, but hard to see with the naked eye because the color difference isn't very distinct.
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reynoldbot
Jupiter
A paper-white mask of evil.
Posts: 790
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Post by reynoldbot on Jun 27, 2007 15:04:12 GMT -4
The difference in color or tone may be indistinguishable from the surface photos, but as you pull back the footprints shrink to tiny dots then disappear altogether, and at the same time the subtle color or tone difference would become apparant. The filters most likely heightened that effect.
There are some great surface photos taken of the landing sites from far away while they were out and about with the rovers. You can distinguish a definite lightening of the soil around where the LM landed. I welcome you and others to find an example, I know 17 had some great shots around house rock (I believe it was 17...).
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Post by gwiz on Jun 27, 2007 15:14:36 GMT -4
I know 17 had some great shots around house rock (I believe it was 17...). Houserock was on 16. The hi-res picture of the 17 site from lunar orbit appears to show rover tracks as well as the LM. Compare #36 and #37 on this page.
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Post by JayUtah on Jun 27, 2007 16:54:55 GMT -4
I suppose it would also depend on what the frequency the photograph was taken in...
That, and more. If you take several photographs of the same scene in several narrow bands (some visible, some perhaps not), then there is an unlimited number of ways in which those photographs may be manipulated or combined algebraically to derive some new image. Each pixel in an image represents the intensity of light reflected from that spot in the scene at the wavelength that corresponds to the filter for that image, usually normalized to the range [0,1].
So hypothetically you may have determined empirically that asphalt reflects strongly at 900 nm but very poorly at 220 nm. So you can define a mathematical function for "asphaltiness" that takes an image P acquired through a 900 nm filter and another one Q acquired at 220 nm. Pixels corresponding to asphalt have a high intensity in P and a low intensity in Q. If we want the corresponding pixel in the output image R to be bright to indicate where asphalt is, then the formula would be something along the lines of R = P/2 + (1-Q)/2. Solve that for each pixel in R using the corresponding pixels in P and Q and you'll have a black-and-white image in which asphalt areas show up brightly compared to others.
That's not to say that the asphalt is brighter. R wouldn't be any real-world picture, but it might resemble one -- especially since areas of shade and shadow would be preserved, as they are in the Clementine image. The Clementine image represents a similar algorithmic product as our example: where lighting can be considered constant, older regolith shows up light and newly-swept regolith appears darker -- not because the material is actually that color, but because that's how the combination formula was written.
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Post by HeadLikeARock (was postbaguk) on Jun 27, 2007 19:08:06 GMT -4
Someday, I hope, someone will go back and find the artifacts. It won't be the first trips back, as they have more important things to explore than old hardware at previously examined sites. And if they did go back to, say the Apollo 17 landing site at Taurus Littrow - well, it just proves that NASA kept those moonsets in mothballs for just such an occasion.
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Jason
Pluto
May all your hits be crits
Posts: 5,579
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Post by Jason on Jun 28, 2007 13:55:10 GMT -4
Viewing the Apollo 15 photographs I notice the ground around the LM looked undisturbed . Wouldn't you need a ground-level picture of what the area looked like before the LM landed in order to determine if the ground had been disturbed?
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reynoldbot
Jupiter
A paper-white mask of evil.
Posts: 790
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Post by reynoldbot on Jun 28, 2007 14:42:11 GMT -4
I know 17 had some great shots around house rock (I believe it was 17...). Houserock was on 16. The hi-res picture of the 17 site from lunar orbit appears to show rover tracks as well as the LM. Compare #36 and #37 on this page. Ratzinger! I knew it was either 16 or 17, I shoulda looked it up. But yeah, there are great examples of that effect in Full Moon by Michael Light.
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Post by Grand Lunar on Jun 28, 2007 17:55:34 GMT -4
What effect do you refer to, Reynoldbot? Asking, as I have "Full Moon".
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Post by Kiwi on Jul 2, 2007 0:58:54 GMT -4
Why can't I see this 165ft to 490ft lunar disturbance on the Apollo 15 lunar photographs? Have you really looked? How about the hi-res version of AS15-84-11324? It shows a distinctly light area around the distant lunar module. There's also an orbital shot, AS15-Pan9814 a15.pan9814.jpg, which shows two craters at top centre, due north of the bend in Hadley Rille, with light areas around them, and roughly 4:30 o'clock from them is the light area around the lunar module. [Edited to change filename.] And AS17-140-21493 , 94 and 95 show a light area east of the Apollo 17 lunar module which is visible just to the right of the top of Split Rock (or Tracy's Rock -- Gene Cernan's daughter). Then there's the telephoto view of the LM in AS17-139-21204 which shows the same light area behind the LM -- to our left. Read the captions at the Apollo Lunar Surface Journal -- they might help. Link at the bottom of every page here.
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Post by Count Zero on Jul 2, 2007 1:48:53 GMT -4
There's also an orbital shot, AS15-Pan9814, which shows two craters at top centre, due north of the bend in Hadley Rille, with light areas around them, and roughly 4:30 o'clock from them is the light area around the lunar module. Is there a place to download hi-res scans of the pan-cam images? The scans at the Apollo Image Atlas are comparatively low-res. I haven't found them at the mis-named Gateway.
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Post by Kiwi on Jul 2, 2007 5:38:09 GMT -4
Is there a place to download hi-res scans of the pan-cam images? The scans at the Apollo Image Atlas are comparatively low-res. I haven't found them at the mis-named Gateway. I found that particular one, No. 9814, 716 kb, at the ALSJ. It's the 18th item in the Apollo 15 Image Library -- but has a slightly different file name: a15.pan9814.jpg (although I suspect that my paranoia about dodgy file names going back to CP/M days -- before that MS-DOS stuff -- when two dots were unacceptable, may have caused me to change it for my own purposes when I downloaded it). The caption says: Pan Camera 9814 ( 716k ) This frame was taken during the CSM Rev. 50 pass over the landing site, two revs after LM liftoff and shortly after 9809 was taken. The LM can be seen near the center of a detail.Other pan photos available there too. These copies show the incredible detail that can be squeezed out of those gigantic negatives, 4.5 inches by 45.24 inches. Copy of the original here, but as you say, very low-res in comparison. www.lpi.usra.edu/resources/apollo/frame/?AS15-P-9814Do I detect a small trail made by the landing LM, or is it just a coincidence? Taken from an altitude of 107 km, it indicates to me that it might be harder to "photograph the flag and the footprints" than some HB's think., especially when the orbital speed of the camera is taken into account.
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Post by 3onthetree on Jul 2, 2007 7:20:07 GMT -4
Is there anything that can be detected on the moon besides the laser reflectors? Can't they detect anything metal? Can they detect anything thermally? Like maybe the LMs or rovers giving off a different heat signature than the surroundings. Is it realy true that it is impossible to detect anything at all. Also didn't the command module circling the moon while the astronouts were on the moon have a lot of scientific instrumentations and cameras that could have recorded the proof? Good question, especially when you consider the Mars Reconnaissance Orbiter has managed to image the Spirit rover and tracks as well as bits and pieces of the Viking landers. All the way through the Martian atmosphere which limits orbital height, unlike the moon where you could arrange a highly elliptical orbit. www.msnbc.msn.com/id/16055585/
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Post by gwiz on Jul 2, 2007 7:51:29 GMT -4
Good question, especially when you consider the Mars Reconnaissance Orbiter has managed to image the Spirit rover and tracks as well as bits and pieces of the Viking landers. All the way through the Martian atmosphere which limits orbital height, unlike the moon where you could arrange a highly elliptical orbit. NASA is planning to launch a similarly capable Lunar Reconnaissance Orbiter next year. Will you accept any pictures it sends back as evidence for the Apollo landings, or will you claim that they are fake too?
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