Why are there no stars seen on the pictures of the moon?

[raven]

There is nothing wrong with an honest question, one the actively seeks an answer.

[Echnaton]

I'll also add that non-hoax questions are best asked in the Reality of Apollo forum, to avoid confusion.  We just assume that new posts in the Hoax Theory area are from hoax believers.

http://www.apollohoax.net/forum/index.php?board=4.0

Please feel free to restart any threads that have been sidetracked. 

[ka9q]

Let me emphasize what Jason Thompson just said. Many hoax claims start with what sound like perfectly reasonable questions. "Why weren't stars visible on the moon?" is a perfectly reasonable question. And there is absolutely nothing wrong with asking questions like those provided you are willing to listen to and honestly consider the answers.

We don't expect you to take the answers on faith, either, just "because we said so" or because we're older and more experienced, with many of us having actually worked in space flight. We're perfectly happy to explain our answers and even have you question them until you understand and see for yourself why they're right. In fact we enjoy doing that. I think we're all repressed teachers or something here.

So go ahead, ask any question you like. As long as you're willing to listen to our answers, we'll be happy to explain them.

[ka9q]

There is nothing wrong with an honest question, one the actively seeks an answer.

Indeed. I like to say that the most distinguishing characteristic of a hoaxer is that they use questions as weapons, not as tools to learn answers.

[smartcooky]

IMO, this question starts out (and progresses) something like this....

1. On earth, the sky at night is black, and we can see stars.
2. On the moon the sky is also black, so why don't Apollo photographs show stars.
3. Since we can't see stars in the Apollo photographs, they must be fakes.

The first problem here us that Q1 is not comparable with Q2. They are not asking about the same criteria; Q1 is about what you can see with the unaided eye and Q2 is asking about what you can see in a photograph of what you are looking at with the unaided eye. These are two very different questions.

If you take a photograph at night on the earth with the kind of exposure times and aperture settings and film speed (really important that last bit) that the astronauts used to take their photographs on the moon, the chances are that you will not see any stars in your photographs.

Also, taking a photograph at night on the earth, (dark landscape + dark sky) does not present the same conditions as taking a photograph on the Moon (bright landscape + dark sky). The nearest equivalent is, as mentioned earlier, is taking a photograph inside a well lit stadium

Here is a shot from our local rugby stadium.


Its taken around 7pm on a clear, cold late winter's night, from the north-east end of the stadium looking south-west. The lights in the gaps beyond the southern stand on left and right are street and house lights on the nearby foothills to the south-west. While walking to the stadium, I could clearly see stars over those foothills, but once inside, stars were not visible, even when I looked straight up.

Another thing that has to be taken into consideration is the human eye. In concert with the human brain, it is a far more sophisticated imaging device that any film camera that has ever been designed by man. Apollo used film cameras; crude and rudimentary image capture devices by comparison with the human eye. The feature of the human eye that really impacts on this issue is that of "dynamic contrast", the ability to "expose" different parts of the image at different levels according to brightness.

Have a look at this photograph


1. What the camera sees: This is about the best result a skilled
photographer could achieve, using available light (in the absence
of any way to reflect light into the child's face)


2. Set the camera to expose for the child's face, and the background
will burn out due to over exposure


3. Set the camera to expose for the background, and the child's face
will be very dark due to under-exposure.


4. What the eye sees: This was taken with a digital camera,
and manipulated in Photoshop by adjusting the tonal range in the
shadow/highlight filter. If there was no reflected into the face of the girl,
there is no way that a film camera could take this shot.

This is the sophistication of the human eye. Dynamic contrast control gives it the ability to lower exposure on bright areas of an image, and increase exposure in darker areas. This is something that no film camera could do, not even the Hasselblad medium format cameras that were used on Apollo.

[Glom]

This is a photo I took in Dubai. Notice the blank sky except for Jupiter next to the building under construction on the left.

[Count Zero]

I found this screen capture from the Firefly episode called "The Train Job":


link

This shot was filmed outside, at night.  That's the Moon behind Mal's head (our moon, not a CGI one inserted later).  Note that it is over-exposed because it's lit by the Sun, whereas the camera is set to show the ground lit by the vehicle's headlights.  Thus, we can readily see that ground lit by incandescent lamps is nowhere near as bright as ground lit by the Sun (assuming the same albedo of the ground - in fact the surface of the Earth (at least, in Southern California where this scene was filmed) is much more reflective than the Moon).

If this camera were on the surface of the Moon with the same settings, the ground would be hopelessly over-exposed.  Yet notice that there are no stars visible in the above image.  Even with cameras set to record a lighted nighttime scene, the stars are too faint to register.  When photographing a scene on sunlit ground (such as the surface of the Moon), there is simply no way that any stars will appear.

[Count Zero]

Missed the edit window.  Here's the pic:

[ka9q]

This is the sophistication of the human eye. Dynamic contrast control gives it the ability to lower exposure on bright areas of an image, and increase exposure in darker areas. This is something that no film camera could do

I think I know why, too. And it's not because the eye is superior to any camera but because it is considerably worse.

More specifically, the eye has only a very small field of view with full spatial and color resolution, the fovea. We have the illusion of seeing everything in front of us because our eyes are constantly darting about the scene, updating the image we keep in our brains. As our eyes move they can refocus and change iris openings, thus dynamically adapting to each part of the picture before updating that part of it in our brains' "frame buffer".

We can now do something like this with cameras and image stacking by taking multiple shots of the scene with a range of exposures and/or focus settings and taking the best of each image for the final result.

As an aside, this illusion we have of continuously seeing the entire scene in front of us is the basis of countless magic tricks.

[raven]

You don't need a great camera when you got excellent post-processing in your wet-ware.

[smartcooky]

This is the sophistication of the human eye. Dynamic contrast control gives it the ability to lower exposure on bright areas of an image, and increase exposure in darker areas. This is something that no film camera could do

I think I know why, too. And it's not because the eye is superior to any camera but because it is considerably worse.

More specifically, the eye has only a very small field of view with full spatial and color resolution, the fovea. We have the illusion of seeing everything in front of us because our eyes are constantly darting about the scene, updating the image we keep in our brains. As our eyes move they can refocus and change iris openings, thus dynamically adapting to each part of the picture before updating that part of it in our brains' "frame buffer".

We can now do something like this with cameras and image stacking by taking multiple shots of the scene with a range of exposures and/or focus settings and taking the best of each image for the final result.

As an aside, this illusion we have of continuously seeing the entire scene in front of us is the basis of countless magic tricks.

You are talking about digital cameras. The Apollo programme used medium format film cameras with low (by modern standards) ASA rating.

Perhaps it would be more true to say the the eye+brain combination is more sophisticated than any film camera.

In particular, the brain can adjust the input levels from different areas of the retina depending on how bright that part of the image is. Its why I can be outside in the garden on a bright sunny day and see into the shady parts and the full sunlight at the same time.

No combination of camera+film can ever do this.

On the Apollo moonshots, the shutter speed was set to 1/250, at ƒ5.6 for objects in shadow and ƒ11 for objects in sunlight. They sometimes used exposure bracketing to ensure good results. The film was probably 125 ASA (at most it would be 160 and that was about the fastest film available at that time). At that film speed, shutter speed ƒ-stop setting, you are never going to capture stars.


EDIT: I should add that there were no actual ASA ratings films at that time. The ASA rating system didn't come in until the early 1980's. They would have rated the special thin emulsion Kodak films used in Apollo in H&D, Scheiners or Weston numbers, but IIRC the fastest commercially available film speed in the 1960s/70s was the equivalent of  about 160 ASA.

[ka9q]

You are talking about digital cameras. The Apollo programme used medium format film cameras with low (by modern standards) ASA rating.

Perhaps it would be more true to say the the eye+brain combination is more sophisticated than any film camera.

You can do exposure and focus stacking with film; just scan it into digital form and treat like digital photographs. But sure, I know what you mean.

My point is simply that modern computers can now do semi-automatically with cameras what the brain does automatically and very quickly with the eye, so the camera+computer combination can now get much closer to the eye+brain combination.

In particular, the brain can adjust the input levels from different areas of the retina depending on how bright that part of the image is.

Exactly. I.e., the brain automatically "stacks" imagery from the eye into a composite image in the brain. The system has the extra advantage that low-resolution peripheral vision can, in real time, detect motion and notify the brain which then redirects the eye to update the changing parts of the image. The brain's attention is also drawn to that area of the scene. (This mechanism is again exploited by magicians.)

The video compression scheme MPEG-2 works somewhat similarly in that most frames consist of changes to previously sent frames, avoiding having to resend the entire frame every 1/30 or 1/24 sec. Here the camera gathers everything and the compressor throws away the redundant parts, while the eye/brain bandwidth is much lower (i.e., the eye itself throws away the redundant information) and is compensated for with a very fast servo mechanism that lets the brain optimize the use of that limited bandwidth.

I wonder if anyone has ever tried a "remote vision" system where the position of the viewer's eye is detected and transmitted to the camera and image compressor to transmit that part of the scene in high resolution, with automatic focus and exposure adaptation. The rest of the scene would be sent in low-resolution black-and-white, simulating peripheral rod vision. The main problem would be in minimizing round-trip control lag. The brain can move the eyes very quickly.

EDIT: I should add that there were no actual ASA ratings films at that time. The ASA rating system didn't come in until the early 1980's.

Are you sure about this? I first got into photography in 1968-1969, and we were most definitely using ASA numbers. (ASA = American Standards Association, former name of ANSI.) Tri-X was ASA 400, Plus-X was ASA 125, Panatomic-X was ASA 32, and so on.

There were also DIN (Deutsches Institut fuer Forschung) numbers, which were logarithmic (essentially decibels), and I am pretty sure the film boxes gave both. It was later (1974) that ASA/DIN numbers were made ISO numbers, e.g. ISO 100/21.

[Count Zero]

EDIT: I should add that there were no actual ASA ratings films at that time. The ASA rating system didn't come in until the early 1980's.

Are you sure about this? I first got into photography in 1968-1969, and we were most definitely using ASA numbers. (ASA = American Standards Association, former name of ANSI.) Tri-X was ASA 400, Plus-X was ASA 125, Panatomic-X was ASA 32, and so on.

There were also DIN (Deutsches Institut fuer Forschung) numbers, which were logarithmic (essentially decibels), and I am pretty sure the film boxes gave both. It was later (1974) that ASA/DIN numbers were made ISO numbers, e.g. ISO 100/21.

I agree.  When I was learning photography in 1975, I was shooting with ASA 100 & ASA 400 film.

[smartcooky]

Modern computers and digital photography simply weren't available in 1969. I am trying to keep to the question about why no stars were seen in the Apollo photos. In doing that, we have to keep within the restrictions of the technology of that time.

Image stacking is really a fancy name for what photographers call "bracketing". Effectively you calculate the optimum exposure, then hedge your bets by taking a shot at one stop either side of that, e.g. if you worked out that 1/250s @ ƒ8 was optimum, you would take one at  ƒ5.6 and another at ƒ11. However, you can't bracket every shot as its very wasteful of film. This would be especially so on Apollo where carrying three times as much film as really needed was not really an option (weight is gold). As I said earlier , they shot 1/250th @ ƒ5.6 in shadow and ƒ11 in sunlight, and only used exposure bracketing for important shots to ensure good results

EDIT: I should add that there were no actual ASA ratings films at that time. The ASA rating system didn't come in until the early 1980's.

Are you sure about this? I first got into photography in 1968-1969, and we were most definitely using ASA numbers. (ASA = American Standards Association, former name of ANSI.) Tri-X was ASA 400, Plus-X was ASA 125, Panatomic-X was ASA 32, and so on.

There were also DIN (Deutsches Institut fuer Forschung) numbers, which were logarithmic (essentially decibels), and I am pretty sure the film boxes gave both. It was later (1974) that ASA/DIN numbers were made ISO numbers, e.g. ISO 100/21.

I should have said that it ASA wasn't a universally accepted standard until the early 1980s

Hurter and Driffield did the original research of film speed (they gave their name to the H&D curve) the late 19th century. A number of different speed systems based on H&D's work appeared in the next several years until the 20s when the logarithmic DIN system came into being. It was based on max contrast and fixed image density

In about 1938 Kodak identified problems with the DIN system (which I won't detail here, except to say that the whole thing fell apart when dealing with very contrasty negatives)> remember we are talking about Black & White film here, not colour, and certainly not C-41 colour which didn't become a commercial reality until the early 1970s.

This problem with film contrast was the reason that ASA (a linear system) was introduced. ASA and DIN were merged into ISO around 1940, using a fixed density + fixed gamma assessment system. and that raises another problem for us. In trying to compare the systems, we need to understand the ASA rating for films then are not the same as the ASA ratings we use now. The systems used various different speed assessment criteria so you can't really make any valid comparisons

AIUI Kodak were asked by NASA to develop special thin films emulsions for the Apollo missions, but the problem with print film than was that the C-22 process used at the time (the forerunner to C-41) was low contrast with a thick film substrate, so it was decided to use transparency film for the colour photography. Kodak had just introduced "Ektachrome" to eventually replace their existing "Kodachrome" transparency film. From memory, Apollo used several different type of film, but the most common ones were;

Kodak Panatomic-X fine-grained, 80 ISO, b/w film
Kodak Ektachrome, 160 ISO transparency film
Kodak 2475 Recording film - b/w super high speed 16,000 ISO (very grainy)

AFAIK, no colour print film was ever carried on Apollo flights

[Sus_pilot]

EDIT: I should add that there were no actual ASA ratings films at that time. The ASA rating system didn't come in until the early 1980's.

Are you sure about this? I first got into photography in 1968-1969, and we were most definitely using ASA numbers. (ASA = American Standards Association, former name of ANSI.) Tri-X was ASA 400, Plus-X was ASA 125, Panatomic-X was ASA 32, and so on.

There were also DIN (Deutsches Institut fuer Forschung) numbers, which were logarithmic (essentially decibels), and I am pretty sure the film boxes gave both. It was later (1974) that ASA/DIN numbers were made ISO numbers, e.g. ISO 100/21.

I agree.  When I was learning photography in 1975, I was shooting with ASA 100 & ASA 400 film.

It's been a long time, but the fastest daylight color film available at the time was Ektachrome at ASA160, in 35mm, 70mm, 120 and 220 variants.  There was a tungsten variant, rated at ASA125, for shooting with 3200k lighting - I think the cyan layer was beefed up in the 160 film to compensate, resulting in the lower rating.  There was also a 64 ASA version for finer grain, but with medium and large format cameras, 160 was just fine (although 4x5 shots with 64 were just unbelievable!).

IIRC, Agfa was in direct line with Kodak and Fuji wasn't really a player until the mid-70's. I think Ilford and Ciba were along the lines of "we've heard of them".

Ektachrome could be "pushed" to higher ratings, just like monochrome films like Tri-X (which I used to shoot at 1600 ASA), but you took major chances with color balance and grain.  Kodak basically said you were on your own if you did it.

The big advantage to using a moderately fast transparency film like Ektachrome was that it was a direct positive image.  Unlike Ektacolor (professional) and Kodacolor (still a damned good film), which used a negative, Ektachrome was a WYSIWIG system where the image wasn't subject to interpretation of the processor.  And since the dyes were built into the film, unlike Kodachrome, the possibility of a disaster in the lab was further reduced (although I never heard of a lab screwing up in processing Kodachrome, not for nothing was there a disclaimer on every box of film sold limiting liability to the film and lab costs).