[Split]Moon hoaxes - split from: Mars Voyage too Soon?

[Southwind17]

You know what the difference between you and me is, Southwind17?

You need to gather mud and sling it if you wish to denounce me - and you're still not fooling anyone.

I needn't say a single word about your style of argumentation - and everyone understands.

See here you're mistaken yet again. I can think of many, many other differences, and I don't need to rely on the support of other people to know they're true!

 

[Southwind17]

Now, then. Would you mind telling me why the "converging" shadows are relevant if you accept that we went to the moon ?

PetersCreek explained it at Post #721, and I accept that explanation. Happy?

 

[Southwind17]

If you want I can ask him, he posts over at ApolloHoax.org

I don't see why not, if you can; we do seem to be getting conflicting figures.

 

[Southwind17]

This statement...and others you've made...lead me to believe that you do not have the grasp of photographic principles that you think you do.

How can you claim to know what I think? I have openly admitted that I am by no means fully informed, let alone an expert, when it comes to photography. I believe I understand much of the basics, though.

As a result of this one in particular, I surmise that you haven't looked through too many wide-angle lenses...and/or haven't done so with a critical eye.

That would be correct.

Perspective distortion is a well-known phenomenon among photographers ...

I am aware of perspective distortion with wide-angle lenses. I am not, however, an avid photographer.

... as is the fact that it is non-linear across the field of view.

I was not aware of this, but I am now. Thank you.

We know that the effect is far more apparent in wide-angle lenses. We know that distances between the subject and lens...and between the subject and other objects in the FOV...are exaggerated at shorter focal lengths. We know that these effects are more pronounced at the edges of the FOV than they are near the optical axis. We choose lenses to exploit and enhance these effects...or to minimize them. In digital post-production, we can (at least in part) correct for these effects. When assembling panoramic montages, dealing with these effects can be a real challenge. There really is no rational basis on which to dispute this reality.

Fair enough.

The fact that you think otherwise also calls into question, the value of your intuitive expectations of the photographic record. They clearly have not served us well in this discussion so far. Given that you've demonstrated little practical knowledge of perspective distortion...or perspective in general, WRT converging shadows...how does your intuition qualify as an tool for reasonably estimating distance, length, or angles measured in perspective?

I never suggested that one should place much reliance on intuition, but that's not to say that we should abandon intuition as a possible starting point. I was merely making an observation in the interests of promoting further discussion, which it has, but not constructively, unfortunately.

But let's try to test my intuition regarding Thabiguys calculation of the distance between the two astronauts as 2.7m:

Assuming Aldrin stands around 1900mm tall incl. boots, helmet, etc., we know the sun angle to be around 15 degrees, so a shadow cast by Aldrin would be about 7m long. Now, we suspect that the lunar surface might slope upwards from Aldrin towards Armstrong, thereby accounting for the apparent difference in height between the two astronauts, and which would foreshorten Aldrin's shadow (although Aldrin's standing in a crater would also seem to at least partly account for the difference, which would put the lunar surface essentially flat, but we'll ignore this possibility, at least for the time being). An incline of around 6 degrees would roughly account for the apparent difference in height of the two astronauts of, for argument's sake, say 200mm, assuming they're standing 2.7m apart. So, how much will an incline of 6 degrees foreshorten Aldrin's shadow? Now, unless I'm mistaken(!) a 6-degree incline of the ground will have the same effect as an increase of 6 degrees to the sun angle on level ground. That gives us an equivalent sun angle of 21-degrees, which derives a shadow length of around 5m. So how far apart does an equivalent shadow length of 5m on flat ground put the two astronauts? Well, we can see from the reflection in Aldrin's visor that Armstrong is standing towards to tip of the shadow. Let's knock of a full metre for good measure. That puts it at 4m. This is not overly inconsistent with Groves' 3.85m! What does this tell us? It tells us at least three things:

1. Sloping ground might well account for the apparent difference in height between the two astronauts (ignoring the lowering of Aldrin by his standing in a crater).
2. Thabiguys critique of Groves' analysis is at least as flawed as he purports to claim the analysis itself is.
3. Intuition might not be reliable, but it can often lead one in the right direction!

So, PC, having requested and received a copy of the Groves analysis, can we expect to see your duly considered, objective critique any time soon, or is your nit-picking pedantry regarding angular distortion the totality of your criticism?

"'Nit-picking pedantry' was that?!", I hear you utter. Well, if and when you do offer your wider views(!) perhaps you'd be so kind as to highlight the impact that Grove's apparent ignorance regarding the linearity or otherwise of angle of view has on his conclusion. Perhaps you could also provide your expert answers to the queries that I raised in Thabiguy's so-called critique.

 

[PetersCreek]

So, PC, having requested and received a copy of the Groves analysis, can we expect to see your duly considered, objective critique any time soon, or is your nit-picking pedantry regarding angular distortion the totality of your criticism?

"'Nit-picking pedantry' was that?!", I hear you utter. Well, if and when you do offer your wider views(!) perhaps you'd be so kind as to highlight the impact that Grove's apparent ignorance regarding the linearity or otherwise of angle of view has on his conclusion. Perhaps you could also provide your expert answers to the queries that I raised in Thabiguy's so-called critique.

Seeing no reason to reinvent the wheel...or flog a dead horse...I'll defer to Thabiguy's evaluation of Groves' work. Seeing even less of a reason for getting sucked into the kind of pissing match you seem to be so fond of, I'll leave the pedantic nitpicking of anomalies to you. As for your queries, rest assured that I'll give them the same prompt attention you gave mine, when I get around to them.

 

[Southwind17]

Assuming my calculation above of the distance between the two astronauts is correct, a quick measure of the vertical FOV of the Aldrin photo, assuming Aldrin stands at 1900mm tall, gives around 3.25m at a range of 4.00m. This converts to an angular measure of around 44 degrees.

Acknowledging that 4.00m was an overly conservative adjustment from 5m, let's assume 4.50m to be more likely. What does that derive? 40 degrees. What is Groves' calculation? 38 degrees. What is Thabiguy's deduction? 49 degrees. Ahem!

 

[Southwind17]

Seeing no reason to reinvent the wheel...or flog a dead horse...I'll defer to Thabiguy's evaluation of Groves' work. Seeing even less of a reason for getting sucked into the kind of pissing match you seem to be so fond of, I'll leave the pedantic nitpicking of anomalies to you. As for your queries, rest assured that I'll give them the same prompt attention you gave mine, when I get around to them.

That would be Thabiguys severely flawed 'evaluation', would it?!

Great to see you're prepared to put your expert money where your expert mouth is!

 

[PetersCreek]

Yes, yes, yes...declare whatever victory you wish. I'm done with this thread and with you.

 

[Southwind17]

Yes, yes, yes...declare whatever victory you wish. I'm done with this thread and with you.

Another one bites the moon dust. Dropping like flies now I've declared my conviction. That seems somewhat odd! Could it be that the drop-outs only coming from those who have received the Groves analysis has some relevance, I wonder!

 

[Southwind17]

I'm a little confused. We're talking about an Apollo 11 picture are we not? (I've not seen Groves' analysis.) If so, then aren't the lenses 38mm? Giving a vertical FOV of 71 degrees...?

If we are talking about the famous Aldrin photo, thats a pretty wide lens.

I think it only appears 'wide' because of the inclination of the camera towards the ground, which picks up features seemingly close to Armstrong's feet. If you imagine the camera being raised to the true horizontal the image captured would probably only just take in Aldrin's feet, and there'd be much more black 'sky' above him. That wouldn't appear 'wide'.

 

[PixyMisa]

You might have noticed that I HAVE OPENLY ACCEPTED NOW THAT MAN WALKED ON THE MOON! By definition, therefore, I am no longer questioning the NASA records and information.

Then why are you still here?

You were wrong. Fine. You admit that. This puts you miles ahead of the vast majority of conspiracy theorists. Congratulations.

But the game is over.

 

[Southwind17]

Then why are you still here?

Do you remember my writing this, it was Post #8?:

As I wrote earlier Jim, I'd be inclined to conclude that, on balance, we probably have walked on the moon, if I had to bet my house. My main beef is with the contrasting shallowness of the counter-arguments put up to seek to disprove the allegations and the seemingly damning analyses and studies.

I have a continuing interest in some of the supporting information, both for and against.

You were wrong. Fine. You admit that. This puts you miles ahead of the vast majority of conspiracy theorists. Congratulations.

I had doubts; I wasn't 'wrong'. My doubts are now much diminished, but not non-existent. I do, however, on most matters, like to keep my mind at least open to a fraction of a degree.

But the game is over.

What 'game' would that be, then? It seems that you and I have different purposes here. Please feel free to wander off.

 

[richardm]

I don't quite follow this. You "openly" concede that man walked on the moon, but have "diminished but not non-existent" doubts? I could understand you saying that you didn't understand how some aspects of the pictures came to be. But how can that amount to a doubt if you genuinely believe that man walked on the moon? What is that you're doubting?

 

[Southwind17]

I don't quite follow this. You "openly" concede that man walked on the moon, but have "diminished but not non-existent" doubts? I could understand you saying that you didn't understand how some aspects of the pictures came to be. But how can that amount to a doubt if you genuinely believe that man walked on the moon? What is that you're doubting?

I still have doubts about whether man actually walked on the Moon, but only to the extent that Richard Dawkins, for example, has doubts that god doesn't exist, i.e. he cannot conclusively prove it.

Whether some of the NASA photos are faked could well be, but not necessarily would be, a completely different, though related, matter. My main interest is in the approaches and techniques that can be taken in attempting to show such photos to be faked or genuine, and not so much now what the implications might be should any fakery or doctoring be proved or disproved.

 

[Thabiguy]

Even though I didn't want to, I have to write yet again, as I must correct a mistake that I had made.

My calculation of the distance of Aldrin's visor was, indeed, flawed. Specifically, at this point:

As the visor spans the horizontal center of the image, we'll use an approximation similar to Groves' to determine the distance.

I don't know what I was thinking; even though we measure the visor horizontally and it is near the horizontal center of the image, the distance from the image center cannot be ignored, as it will affect the result. I apologize to the readers.

Let's do a better calculation. We'll consider points A and B on the photograph:
A = (-2.04 mm, 21.35 mm)
B = (3.64 mm, 22.24 mm)
These points are arbitrarily selected to correspond to edges of Aldrin's visor.
(Note about accuracy: Although the points are listed with two digits after the decimal point, to allow readers to trace them to individual pixels on the high resolution scans, it would be unrealistic to assume greater accuracy in measurement than about 0.1 mm. Such inaccuracy will translate to less than 0.1 m in the resulting distance.)
Point P (the model pinhole) is at 3D coordinates (0, 0, (photo width/2)/tan(FOV/2)).
Assuming photo width of 52 mm and FOV of 49.2 degrees, the sides of the triangle PAB are then (values rounded for listing, unrounded for subsequent calculations):
|AB| = 5.75 mm
|PA| = 60.7 mm
|PB| = 61.1 mm
From the cosine law, the angle APB (the calculated angular width of Aldrin's visor) is about 5.4 degrees, which, assuming actual width of 280 mm, would give distance of 2.97 m, or about 3 m between the visor and the camera. This differs by 30 cm, or 10% from my previous estimate.

This change affects my subsequent comments on Groves' analysis at one other point: rederivation of Groves' result of 1073 mm yields 1.15 m, not 1.05 m, increasing the difference from about 1 inch to about 3 inches. The rest of my comments are not affected in any way.

Some forum members apparently have trouble comprehending written text, so I will point out once again:

• This is the distance between the edges of Aldrin's visor and the camera; the distance that Groves tried to calculate. Aldrin is a large object and different parts of his body will have different distances from the camera; his feet will be considerably farther away, for example. Distances from other points, such as the front of Armstrong's left foot, or back of Armstrong's right foot, will be different still.

In other words, the distance between Aldrin's visor and the camera cannot be used to estimate the length of Aldrin's shadow. Distance between astronauts' feet will be greater than that.



Finally, I would like to address the silly claim that Groves' figure of 37.987 degrees is a better estimate of the FOV than NASA's figure of 49.2 degrees. But how could we verify the FOV? If only we had a picture of an object whose distance and size are both known...

Well, guess what? We do. This picture of the Earth taken from lunar orbit is very conveniently at the center of the image. Its edge goes almost directly through the optical axis, minimizing distortions and making the distance-angle conversion simple and straightforward.

The size of the Earth on the photograph is about 1.96 mm, or 1.9-2.0 mm if you wish to account for inaccuracy.

NASA's FOV of 49.2 degrees, image width 52 mm:
estimated angular size = 1.98 degrees (1.92-2.02 degrees)

Groves' FOV of 37.987 degrees, image width 52 mm:
estimated angular size = 1.49 degrees (1.44-1.52 degrees)

Angular diameter of the Earth, as seen from the Moon during the Apollo 11 mission, was about 1.9 degrees. I think it's unnecessary to say more.

 

[sts60]

I still have doubts about whether man actually walked on the Moon, but only to the extent that Richard Dawkins, for example, has doubts that god doesn't exist, i.e. he cannot conclusively prove it...

So is it correct to say you accept that men landed on the Moon, but doubt they actually walked on it? You seemed to be hinting at that position earlier.

 

[Belz...]

PetersCreek explained it at Post #721, and I accept that explanation. Happy?

Fair enough.

 

[Cuddles]

I think it's unnecessary to say more.

Don't worry about the nuts, some of us appreciate good work when we see it.

 

[Southwind17]

Finally, I would like to address the silly claim that Groves' figure of 37.987 degrees is a better estimate of the FOV than NASA's figure of 49.2 degrees. But how could we verify the FOV? If only we had a picture of an object whose distance and size are both known...

Well, guess what? We do. This picture of the Earth taken from lunar orbit is very conveniently at the center of the image. Its edge goes almost directly through the optical axis, minimizing distortions and making the distance-angle conversion simple and straightforward.

The size of the Earth on the photograph is about 1.96 mm, or 1.9-2.0 mm if you wish to account for inaccuracy.

NASA's FOV of 49.2 degrees, image width 52 mm:
estimated angular size = 1.98 degrees (1.92-2.02 degrees)

Groves' FOV of 37.987 degrees, image width 52 mm:
estimated angular size = 1.49 degrees (1.44-1.52 degrees)

Angular diameter of the Earth, as seen from the Moon during the Apollo 11 mission, was about 1.9 degrees. I think it's unnecessary to say more.

I actually think it would be far better to show where Groves' calculation of the FOV is wrong, which to my mind is the only conclusive approach. The photo of the Earth approach seems too far removed from what it is we're trying to ascertain, and contains inherent uncertainties. Can somebody not show Groves' calculation to be wrong, other than claiming that he's not telling the truth?!

 

[Southwind17]

So is it correct to say you accept that men landed on the Moon, but doubt they actually walked on it? You seemed to be hinting at that position earlier.

Not at all. Please don't get me wrong; I'm not one for smart arse word games. If NASA was capable of putting a manned LM on the lunar surface I have absolutely no reason to think that those guys couldn't then go for a stroll. Seriously, the answer's: No.