Light Fall Off in Apollo Missions - American Moon Documentary

Nandude

New Member
The claim in the American Moon documentary is that some of the photos show that they were taken in a studio with spotlights, and by extension on earth in a studio, because of the way the light falls off in the photos. The premise being that, given how far away the sun is, the entire landscape of the moon should be equally lit.

"From the documentary, "when the sun illuminates a large a large flat expanse, the light reaches every visible point with the same intensity. Whether we observers an area closer to us or in the distance the luminosity of the ground is practically the same everywhere"

Example from the documentary:

upload_2019-12-3_21-7-28.png

One example of light falloff from the Apollo photos is as11_40_5875.jpg shown here:



An illustration of what they mean from the documentary:

upload_2019-12-3_21-0-28.png

So they claim that the light should evenly covering the landscape as shown in this example here:

upload_2019-12-3_21-1-27.png

Does anyone know how to explain the light falloff in these moon photos?

They do address common suggestions like heiligenschein which is a spotlight effect that happens when the sun is directly behind the photographer. But as they put it in the documentary, "But many of the photos show the hotspot effects when light is at the side and not behind photographers head". Which is true.

My gut reaction is there are varying things going on and one explanation will not cover all the pictures with this falloff effect.

One tack I took was finding photos that do have the moon's landscape evenly lit. For example AS11-39-5741HR below. You can also see a bit of heiligenschein around the shadow of the LM as the light is coming from the rear. However, the light does also evenly cover the entire surface. My thinking is how would this be possible of not taken on the moon? While it doesn't explain the pictures with light falloff it does make it probable that are anomalous, given that we have photos clearly taken from the moon.



But what I would really like are some good explanations of how we get light falloff. There are several examples given in the documentary so lets start with as11_40_5875.
https://spaceflight.nasa.gov/gallery/images/apollo/apollo11/hires/as11_40_5875.jpg


I do have the relevant section of the documentary edited and uploaded if anyone cares to see the whole thing.

Thanks
 

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An original scan of the film image can be seen here:
https://live.staticflickr.com/743/21447630133_ccc36f4edc_o_d.jpg


Metabunk 2019-12-04 06-13-36.jpg

Contrast adjusted (evenly across the image):
Metabunk 2019-12-04 06-14-14.jpg

Blurred to average out the brightness
Metabunk 2019-12-04 06-15-03.jpg

I think the idea of a fall-off with distance is something of an illusion. There's a bright region in the upper right, and in the lower left. The differences seem mostly to do with the terrain angle, and where they have been walking (hence disrupting the normal surface albedo.

The lunar surface has some interesting optical properties because of the very fine dust on the surfaces, which forms delicate structures over millions of years due to the lack of atmosphere. This can lead to unexpected angle specific changes in reflectance which might play a part here. But I think it's really pretty much down to slope.
 
so lets start with as11_40_5875.

I really don't see a 'fall off'. I see a 'side off' (left of blue line) ... which based on the shadows can't actually be a 'side off'.

why didn't they pick my pink area as the 'fall off'?
bb.png


any maybe slight discrepancy I see, seems to just be because the photo gets blurry with distance so the light and dark sand in the foreground that we see so pronounced are kinda blurred together as the camera focus blurs.
 
Hey Mick, thanks for the original scan image. In MOON HOAX: DEBUNKED! by Paolo Attivissimo (and also his site) he does mention that the original scans don't show this effect but I hadn't found any examples to verify. What did you search to get that? Clearly my skills are up to yours! That's a big help. I'm trying to debunk this one because a friend challenged me...

@deidre - I see what you mean. They definitely stretch the idea of a spotlight hotspot. The hotspot should be round an not have one flat side. Unless of course it's the flat-earthers type sun :p.
 
Hey Mick, thanks for the original scan image. In MOON HOAX: DEBUNKED! by Paolo Attivissimo (and also his site) he does mention that the original scans don't show this effect but I hadn't found any examples to verify.
The original shows the same areas of slight variation in light and dark, just different contrast.

What did you search to get that?
I just searched for the file number as11_40_5875, and picked the result from the Project Apollo Flickr page.
 
one thing they do in this part of the documentary is use a scan of the "Tourist" photo (as11-40-5903 hr) is point out the falloff and then raise the contrast to show it more. Is there a fallacy in raising the contrast? Even if the images used have been reproduced over time and enhancing the light falloff effect or altering the image, wouldn't that mean that the light values were still different, if even imperceptible, on the originals? Is there a fallacy in doing that? I don't know enough about photography to know but it feels like there's a fallacy on their part in there. From the documentary:

upload_2019-12-4_10-58-49.png

Then they raise the contrast

upload_2019-12-4_10-59-11.png

If I use the same original Hassleblad image from flikr, it's not nearly as pronounced but there is more light around the astronaut. Maybe due to the reflection off his suit and maybe the LM leg? But the rest of the surface looks pretty evenly lit. Does it mean anything that over time, through reproductions that the fall-off effect is generated?

 
:) look in his visor. the hot spot there seems to be way out on the horizon.

Interesting... could that be a heiligenschein effect because essentially the visor is now the camera and the light is almost directly behind it?. Good catch, I didn't even see that.
 

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Weird how there's a hotspot around the dude wearing white
But right behind the legs there is nothing "hot". A suit redistribution would certainly illuminate that part.

I think the hotspot behind the astronaut is rather a matter of slope, towards the sun and away from it.
 
It seems that, given how dark the Moon is, they would have needed auxiliary lighting of some kind to take pictures. It could be that these light anomalies are caused by lighting from the spaceship or the Moon Rover.
 
It seems that, given how dark the Moon is, they would have needed auxiliary lighting of some kind to take pictures. It could be that these light anomalies are caused by lighting from the spaceship or the Moon Rover.
No, it was all in full sunlight. Brighter than on Earth at noon, but with darker shadows than on Earth, as there's no scatter of light in the atmosphere. No extra lights were needed.
 
But right behind the legs there is nothing "hot". A suit redistribution would certainly illuminate that part.

I think the hotspot behind the astronaut is rather a matter of slope, towards the sun and away from it.

I think you might be right there since right underneath it's darker because of the slope toward the camera
 
It seems that, given how dark the Moon is, they would have needed auxiliary lighting of some kind to take pictures. It could be that these light anomalies are caused by lighting from the spaceship or the Moon Rover.

NVIDIA did a really cool vid where they simulated a picture using a physics engine that shows how the light bounces off the different surface, ie the astronauts and the regolith, to show how it was all just the one light source:


Source: https://www.youtube.com/watch?v=syVP6zDZN7I
 
The Nvidia video is very good.

The brighter areas are just from reflected sunlight off of the two astronaut's suits. The hotspot is from the photographers suit and also the subjects suit. The fall off is because the reflected light from the backside of the subjects suit is falling off.
 
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