Exposing PseudoAstronomy

October 20, 2008

The Apollo Moon Hoax: “No Stars” Claim and an Explanation of Dynamic Range


All posts in this series:

Continuing my sporadic series on claims made by people who believe that the US never landed humans on the moon, I am going to address one of the simplest and yet most prolific claims:  There are no stars in the pictures of the moon.  After all, the sky is black and without an atmosphere we should be able to see stars … right?  WRONG

I am going to address this in three ways, first by proposing questions which demonstrate the lunacy (pun intended) of this claim when you actually think about it.  Second, I will address the reason why we don’t see stars in a qualitative way, and third I will explain dynamic range and why stars aren’t visible in a quantitative way.

Method 1 – Why This Doesn’t Make Sense

The claim effectively goes:  On the moon without an atmosphere in the way, the sky should be filled with stars.  Since there aren’t stars, it must be fake.  In fact, it must be a really bad fake because NASA knew that they wouldn’t be able to figure out where every star goes on their black backdrops for their sets because other people would realize they are in the wrong place, so they just eliminated the stars all together and made the backdrops completely black.

This shows one of the major problems with conspiracy theories of this scale – you have to grant the conspirators a huge amount of power, intelligence, and influence, yet they have to be so unbelievably dumb as to make simple mistakes that the conspiracy theorists can then point out.

When I do my planetarium show on the Apollo Moon Hoax (“Why We Did NOT Not Land on the Moon”), I have the operator bring up the star projector along with a 360° lunar panorama to “simulate” what the conspiracy theorists say it should be like if we’re on the moon.  And it’s a good simulation.  Why?  Because the stars should be in the same place as they are on Earth!  Even though the moon is 384,400 km from Earth, that’s pretty much nothing in relation to where we would see stars from the Apollo cameras.  Only if the astronauts were to do very precise astrometry with very long-focal length lenses (as in telescopes) would they be able to discern any deviation from where the stars would appear from Earth, and even then, it would only be for the very closest stars to our solar system.

So, the fact that we have great planetarium star projectors that simulate the positions of thousands of stars means that NASA should have easily been able to figure out where to put the stars.  And not just that, but if NASA couldn’t figure out where to put the stars – when they had 1 out of every 360 Americans working on the Apollo program in some manner – how would someone else be able to figure out that they were in the wrong place when the exact orientation and location of every single Apollo photograph is simply not available to them?

It simply doesn’t make sense for NASA to have purposely left the stars out.

Method 2 – A Qualitative Explanation of Dynamic Range

Dynamic range (discussed with numbers below in Method 3) is the ability to observe/record/detect a range of values.  For example, if you look at an oven thermometer, it probably has numbers for 100° to maybe 500°.  That’s the dynamic range of it, it can’t record anything below 100° nor about 500°.  Same thing with a car’s speedometer – its dynamic range is probably 0 mph to around 150 mph.  Any speed above 150 and it’s useless.

With cameras, it’s a little more complicated because you can control the “window” of dynamic range with things like shutter speed and aperture.  So let’s go back to the thermometer example – the one above has a range of 400°.  Let’s say I re-calibrated it such that it can now record between -100° and +300°.  Its dynamic range is still the same, but I’ve changed what temperatures it’s sensitive to in the same way changing the shutter speed of a camera will change what light levels can be captured before they’re too dim to be recorded or too bright to be completely washed out.

This is what happened with the stars:  The dynamic range of the camera film was too small to both properly expose the lunar surface and to record stars.  And since, for the most part, the astronauts went to the moon to explore the lunar surface and not do stellar astronomy, they didn’t take pictures of the stars …

… except they actually did (example photo on the right).  Conspiracy theorists never actually bring this up because it’s one of those incontrovertible pieces of evidence that we actually did go to the moon.  Ultraviolet light is blocked by our atmosphere and so it doesn’t reach the ground (for the most part), which is a good thing for life such as us.  To do UV astronomy, you have to go above Earth’s atmosphere, and so the Apollo 16 astronauts actually brought UV cameras to the moon.  They took photographs that were made available, and they were the first of their kind showing features in the far-UV spectrum.  Many years later, when space-based UV telescopes became operational, they confirmed that the Apollo 16 photographs were real because they showed the same things.

Method 3 – A Quantitative Explanation of Dynamic Range

This is a discussion of dynamic range with more numbers.  For ease of argument, let’s say that the dynamic range of the camera film used by Apollo is between 1 and 100.  If only 1 piece of light or less hits the film, the film records it as black.  If 100 pieces or more hit the film, it’s recorded as white.

Now let’s say that the moon reflects between 6000 and 20,000 pieces of light per second, while any one reasonably bright-looking star hits the moon with more like 1 piece of light per second.  (This is actually the approximate scaling between the two.)  This is not because of any atmospheric effects (Earth’s atmosphere transmits over 90% of visible light through it, and it wouldn’t selectively screen out star light from moon light, anyway), but simply because the stars are much fainter because they’re much farther away.

As you can see right away, we have a problem:  Our film can only record between 1 and 100 counts, but the moon reflects over 100 times that amount of light per second.  That’s why we have a variable shutter speed.  We can expose the film for less than 1 second.  In this case, if we expose the film for 1/250th of a second, then the film should only pick up between (6000/250 = ) 24 and (20,000/250 = ) 80 pieces of light in that picture.  Since 24 and 80 are both between 1 and 100, then we have properly exposed the moon, getting its brightness within the dynamic range of the camera.

Now let’s look at the stars.  In that 1/250th second photograph, there’s only a 1 in 250 chance that a piece of light will enter the camera and be recorded by the film.  It’s very unlikely.  And so, to the film, that star wouldn’t even be there – it wouldn’t be detected – because it’s below the dynamic range of the film.

Now let’s say you actually did want to photograph the stars.  With 1 piece of light per second, you would probably want to take a picture for around 50 seconds (to get it in the middle of your dynamic range).  But, if you take a picture for 50 seconds, the amount of reflected light off the moon would be over 300,000 counts, and this is way above our dynamic range limit of 100 counts.  So while that star may be properly exposed in 50 seconds, the moon itself would be over-exposed and appear all white.

That is why the dynamic range of the film is not good enough to see both stars and the moon’s surface in the same length of exposure


To summarize, the basic reason there are no stars in the Apollo photographs of the lunar surface and sky is because the cameras were set to expose the lunar surface properly, and those exposures are too short to record stars.

In fact, you can easily do this experiment yourself:  On a night when there’s a fairly full moon out, or even a half-full moon out, go outside and try to photograph it.  If you use an aperture somewhere around 4.5 to 6.3, you will likely need a shutter speed between 1/200 and 1/100 of a second to properly expose the moon.  Now look at your photos.  Do you see any stars?  The answer will be “no.”

Now try to photograph the stars.  You will likely need to expose for at least several seconds in order to see any stars in your picture.  Now go back to the moon and use the same exposure settings, aperture and shutter speed.  You may get stars in the field this time, but the moon will be a pure white ball, over-exposed.

This simple experiment, along with all the arguments above, should clearly show why the claim that there are no stars in the Apollo lunar photographs does not mean that the lunar landings were faked.

14 Comments »

  1. Oh my god enjoyed reading your blogpost. I submitted your rss to my reader!!

    Comment by PevygumsPoeve — November 30, 2009 @ 8:33 am | Reply

  2. There actually ARE some Apollo 14 lunar surface pictures that managed to capture the planet Venus. It’s from a series near the end of an EVA that shows the earth high over the LM. They correctly expose the shadowed side of the LM so the exposure times were longer than those of the sunlit surface.

    If there was just one picture we wouldn’t be able to tell for sure that it’s Venus because dust scratches were common on those pictures. But it shows up in every photo and in the correct place.

    And it’s still just barely visible despite being the third brightest object in the lunar sky, after the sun and earth (Venus is also the third brightest object from earth, after the sun and moon). So when you compare the brightness of Venus to that of the stars, it becomes obvious from these pictures that regular stars were just way too dim to show up in Apollo lunar surface pictures.

    Comment by Phil Karn — February 18, 2010 @ 10:48 am | Reply

  3. Great Debunk work. As both a film student and a student with interest in astronomy, I’ve had this exact same problem.

    Comment by Emperor — September 3, 2010 @ 5:03 pm | Reply

  4. we didn’t see any stars because its daytime all the time on the moon. Do you see stars when it is daylight on earth? well, your reason is probobly true too, but you wouldnt have seen any stars either way.

    Comment by Lone — October 20, 2010 @ 12:44 pm | Reply

    • It’s not actually daytime all the time on the moon. But every Apollo landing did occur in the daytime, more specifically early morning at the landing site to have the best view during the landing. It also kept temperatures reasonably low.

      Even Apollo 17, the longest visit, spent only 3 days on the moon. Because the moon turns on its axis only about once per month, they still left before local solar noon.

      Comment by Phil Karn — May 23, 2011 @ 1:37 am | Reply

      • Kept temperatures reasonably low? I didn’t realize the vacuum of space and the lack of an atmosphere on the moon would transfer heat from the sun.

        Comment by Scott — August 15, 2015 @ 3:01 pm

  5. I guess this picture is fake as well, because I sure don’t see any starts in it.

    http://www.nasa.gov/mission_pages/station/multimedia/gallery/iss030e078532.html

    Comment by garon — February 23, 2012 @ 2:16 pm | Reply

  6. does this go for video as well or is there a difference

    Comment by kc — October 11, 2012 @ 12:51 pm | Reply

    • This is usually even worse for video — most video cameras have even less dynamic range than film or digital still cameras today.

      Comment by Stuart Robbins — October 11, 2012 @ 1:28 pm | Reply

  7. “To summarize, the basic reason there are no stars in the Apollo photographs of the lunar surface and sky is because the cameras were set to expose the lunar surface properly, and those exposures are too short to record stars.”
    “Now go back to the moon and use the same exposure settings, aperture and shutter speed. You may get stars in the field this time, but the moon will be a pure white ball, over-exposed.”

    Yeah right. What about Apollo 17?
    Why you can see stars and the sun in photos taken closely together?

    Notice these HR (high resolution) SEQUENTIAL B&W photographs with the exposure set to expose the lunar surface properly.
    Notice the white stars in the photographs: (Use the high res iPad or large PC screen):

    This despite the sun being out nice and bright 2 photographs later: 20740HR.jpg

    From this Film magazine:
    https://www.hq.nasa.gov/alsj/a17/images17.html#MagH

    “but the moon will be a pure white ball, over-exposed,” to quote you. Oh really?
    Was the camera “using the same exposure settings, aperture and shutter speed,” to expose the lunar surface properly 2 photographs later? Highly likely.

    Nice try in your explanation without using actual data obtainable from NASA. Now explain away the facts in these photographs.
    Your explanation to explain away a hoax isn’t working. The cameras were able to pick up “stars” – so why not in all the photos in the Apollo landings when cameras were not directed at the sun?

    Maybe the white stars are dust on the lens, you know the dust you claim can’t be kicked up by the LM Descent Engine.
    Or maybe they are pinpricks in a stage background cloth, or entered in the photographs by NASA after the fact when they realized by Apollo 17 their goof.

    hq.nasa.gov/alsj/a17/AS17-136-20726HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20733HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20734HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20735HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20736HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20737HR.jpg

    hq.nasa.gov/alsj/a17/AS17-136-20738HR.jpg

    Is this an overexposed pure white ball? – 2 photos later?
    Why isn’t it overexposed with the camera directly at the sun when the camera was set to expose the lunar surface just a few photos earlier?

    Because it’s not the sun. It’s a studio light.

    hq.nasa.gov/alsj/a17/AS17-136-20740HR.jpg

    Comment by Scott — August 15, 2015 @ 4:44 pm | Reply

  8. Apollo 15
    Notice the photo with the stage lights on the bars above:
    http://www.lpi.usra.edu/resources/apollo/frame/?AS15-89-12015

    Notice the same photo cropped on NASA’s site:

    Comment by Scott — August 15, 2015 @ 5:02 pm | Reply

  9. Please, don’t aim the camera too high. You may take a photo of the overhead studio lights:

    http://www.lpi.usra.edu/resources/apollo/catalog/70mm/magazine/?89

    Comment by Scott — August 15, 2015 @ 5:05 pm | Reply

  10. 1/ ABove picture 27040HR clearly shows a light source VERY close to the moon buggy since the shadows behind the buggy go at least in FOUR different directions. That is NOT possible if the light source is millions of miles away. that light source cannot be more 50 feet away.
    2/ All, please check out this official site
    http://Www.lpi.usra.edu./resources/Apollo/frame/?AS14-66-9903 this is just one picture of the official Lunar and Planetary Institute Apollo archive where you can find every single Apollo picture ever taken (a few thousand of them) . So the guy showing a picture way above with many stars in it, pls let me know the picture’s AS number at LPI so I can confirm.
    3/ I have read carefully all above explanations about why a camera cannot record stars.
    A/ today with any cell phone you can look up the sky and an App will show you the names of all stars visible for you. a great App, you should have it.
    B/ The guy with the official explanation states that those millions of stars are actually there but the cameras cannot see them. I have just watched one of the info sessions with returning astronauts and all three of them stated that they did not ever see any stars. It seems that the aperture of their eyes were also set to the “wrong” opening and timing Remember, all landings are at dawn, with not enough sun light to block out ALL stars to the naked eye!. Well, stranger things have happened on the moon did not they?
    By the way my above AS14-66-9903 example also shows a very close light source.
    Interestingly, however, all these bad lightning Examples DO NOT prove that they did not go to the moon. NASA openly admits that they had a bunch of studio excersizes here on earth and a bunch of these pictures are from these studio sets. That is fine with me. My question is: why mix and match studio pictures (and videos) with actual moon pictures and videos and sell them ALL as authentic real things. That is immensely STUPID and gives fuel to people questioning the authenticity of the whole program.
    Finally, FYI, the European Union, Russia (who are much better than USA in space of anything, and here I will NOT take any counter argument,because if you do not believe that then you are either incredibly ignorant or incredibly stupid, a few examples, first orbiter, first animal up, first man up, first woman up) , South Korea, China, Japan, India ALL have thought of sending men to the moon (or beyond) at some point of time, alone or in partnership with one another but all had come to the conclusion that with current technology it simply cannot be done. Conclusion ALL these countries are stupid, they just should have bought the 60s technologies from the USA for $99.
    Cheers Steve from Toronto, Canada

    Comment by Steve K. — February 8, 2016 @ 1:08 pm | Reply

  11. Wrong. Although your explanation of cameras may make sense, it does not explain why noel Armstrong himself told sir Patrick Moore than he did not visibly see stars, nor planets, from the moon.

    Comment by keith — June 2, 2016 @ 2:42 pm | Reply


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