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Post by gwiz on Nov 28, 2006 7:06:33 GMT -4
I asked Tuttle and he said he digitally altered the photos and gave examples like removing the seamlines and blckening the sky. Tuttle isn't NASA. The fact that there are similar white spots all over the picture, not just in the sky, does rather rule out stars as an explanation.
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Post by Jason Thompson on Nov 28, 2006 7:15:49 GMT -4
I asked Tuttle and he said he digitally altered the photos and gave examples like removing the seamlines and blckening the sky.
In the pictures you are looking at? Or have you just assumed he means in every single image? The reference to removing seamlines suggests he was referring to the composite images like panoramas assembled from the individual pictures taken by the astronauts.
as for the stars, what causes these
Do you know which picture that is? Can you find other versions of it online or in books? Have you even bothered to try?
A white speck in the black sky is not necessarily a star. In fact, given all the other evidence offered, it is a safe bet that it is not a star. It is more likely to be a speck of dust on the scanner used to reproduce the image. That is why I ask about other versions of the image, to see if the speck is visible on others. Or you culd look for other images from the same source to see if those specks crop up again.
I will say this as many times as necessary: the difference in brightness between the sunlit lunar surface and a star is several orders of magnitude, and is well beyond the dynamic range of the film. That is to say you can have properly exposed pictures of the lunar surface with no sars, or you can have pictures of stars with the lunar surface so washed out it is nothing more than a bright flare that will probably bleed across the film and blot out the stars anyway.
But even that ignores two basic constraints. First, I am not sure the cameras could be set for long enough exposures to capture the stars, and even if they could the astronauts certainly could not have held it still long enough to expose the pictures without getting motion trails. Second, they went there to explore the Moon, not to take pictures of stars that look no different from there than they do on Earth. The only stellar photography done on the Moon was with a UV camera on Apollo 16, and that's because you cannot see the stars in UV through Earth's atmosphere.
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Post by lionking on Nov 28, 2006 7:21:00 GMT -4
"Second, they went there to explore the Moon, not to take pictures of stars that look no different from there than they do on Earth."
wouldn't they look more bright, with no atmosphere?
"the difference in brightness between the sunlit lunar surface and a star is several orders of magnitude, and is well beyond the dynamic range of the film."
given that the stars will be so bright, wouldn't they be able to capture them as they captured the bright sun?
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Post by Jason Thompson on Nov 28, 2006 7:49:15 GMT -4
wouldn't they look more bright, with no atmosphere?
Not hugely, no, and in any case what difference does that make to a photograph? They will be in exactly the same positions, so a picture taken from the Moon will look just like a picture taken on a clear night on Earth.
PLease take note of this: remove yourself from Apollo for a second and go and search for any picture taken in space of a sunlit object that inlcudes stars. Even the Voyager images of Neptune, where the sunlight is much lower, had no stars in. The ones where they did capture stars used a mask to blot out Neptune itself (they were trying to image its dark rings, so needed much longer exposure times), but where Neptune does intrude on the image it is so bright it is nothing but a blurry white blob.
given that the stars will be so bright, wouldn't they be able to capture them as they captured the bright sun?
Not even close. You seem to be missing the critical point here about how things are lit. The lunar surface is lit by the sun. It on average reflects about 7% of the light that hits it. 7% of full sunlight is still much brighter than any star. The sun, of course, is much much MUCH brighter than the lunar surface, and therefore you cannot avoid capturing it if you happen to be aiming your camera in the right direction. But note that it looks HUGE in the photos, because it is so bright.
A note about brightness, for comaprison.
Sirius, the brightest sar in the night sky, has a magnitude of about -1. The magnitude scale is logarithmic, and the brighter something is the lower its magnitude. An object of magnitude 1 is 2.5 times as bright as an object of magnitude 2, which is 2.5 times as bright as an object of magnitude 3, and so on.
Sirius is magnitude -1, roughly. Venus appears as magnitude -4, so is 2.5x2.5x2.5x as bright (about 16x). The sun is magnitude -26. This works out to be, very roughly, 9,000,000,000 times as bright as Sirius, the brightest star in the sky. Not even the absence of an atmosphere is going to allow Sirius to appear bright enough to be captured alongside something as bright as the lunar surface being lit by something that bright.
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Post by james on Nov 28, 2006 7:53:27 GMT -4
given that the stars will be so bright, wouldn't they be able to capture them as they captured the bright sun? A star, be it viewed from Earth or in space, is still a tiny speck of light and is not bright enough to show up on a quick exposure of film. The astronauts may have seen stars with there own eyes at certain times depending on the lighting conditions, but to capture them on film you need a long exposure. Long enough to require a tripod (or something that can keep the camera steady). So no, they can not capture the stars like they do with the Sun. The Sun is incredibly bright due to its close proximity to Earth.
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Post by gwiz on Nov 28, 2006 8:04:26 GMT -4
The astronauts may have seen stars with there own eyes at certain times depending on the lighting conditions, but to capture them on film you need a long exposure. Long enough to require a tripod (or something that can keep the camera steady). The hoax supporters like to produce quotes from astronauts and cosmonauts saying how bright the stars were from their capsules. They always edit these quotes to remove the significant detail that these stars were seen when on the night side of the earth. On the day side, with competition from the sun, it is extremely difficult to see stars. You would have to look in a direction away from both the sun and the earth and wait several minutes for your eyes to adapt.
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Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
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Post by Al Johnston on Nov 28, 2006 8:25:35 GMT -4
Anyone else getting that "Father Ted" feeling?
To paraphrase, Yes the stars are bright, they're also very far away...
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Post by lionking on Nov 28, 2006 9:46:29 GMT -4
does the moon have a night ? (bcz I see some dark photos )
why do we need long exposures to capture something in a certain lighting condition that the astronaut's could see through
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Post by gwiz on Nov 28, 2006 10:06:56 GMT -4
does the moon have a night ? (bcz I see some dark photos ) Do you really have this total lack of knowledge, or are you pulling our chains? Of course the moon has a night side, that's why it shows phases, but all the Apollo landings were on the day side. Because our eyes can cope with a much greater brightness range than film can.
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Post by lionking on Nov 28, 2006 10:17:51 GMT -4
gwiz that's not what I meant. I meant are there dawns like on earth where the sun decreased radiation where the astronauts landed?
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Post by Jason Thompson on Nov 28, 2006 10:29:23 GMT -4
does the moon have a night ? (bcz I see some dark photos )
Yes, of course it does. However, that has nothing to do with the pictures. All the landings happened during the day. The fact that some seem brighter than others is to do with exposure settings and which way the camera was pointing. Lunar soil tends to reflect light preferentially back in the direction it came (hence the full Moon appears brighter from here than any other phase). If you take a picture with the sun behind you you'll pick up the soil as brighter than if you aim in the direction of the sun.
why do we need long exposures to capture something in a certain lighting condition that the astronaut's could see through
Because a human eye and a piece of film are very different things. Your eye responds to different light levels not only by altering the size of the pupil to let more or less light in, but by chemicals such as rhodopsin that actively change the sensitivity of the cells that pick up the light. If you step outside from a brightly lit room to a dark, moonless night your pupil will dilate immediately to let in more light, but it will take several minutes for the production of rhodospin in your eyes to increase to the level where you can see anything but the brightest stars. Shine light in your eyes again and you lose all that sensitivity in less than a second.
A camera doesn't have the advantage of altering the sensitivity of the film in it. The only way to capture dim objects is to keep the shutter open longer and let more light fall on the film. The astronauts could only see the stars by looking up such that neither the sun nor the lunar surface was anywhere in their field of view, and then they had to wait for their eyes to adapt. They didn't do it much because they were rather busy. On the spacecraft they had to turn off all the interior lights and wait until the windows were all oriented away from the sun, then let their eyes adapt before they could see any stars at all.
I meant are there dawns like on earth where the sun decreased radiation where the astronauts landed?
Yes and no. There is a sunrise on the Moon, and the sun moves across the sky such that the angle of the radiation changes. All the lunar landings happened in the early morning in terms of time on the Moon, with the sun low in the sky.
However, there isn't a gradual increase in brightness to the same extent that there is here. On Earth the atmosphere refracts the light so that we see the sky lighten considerably before the sun actually comes up.
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Bob B.
Bob the Excel Guru?
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Post by Bob B. on Nov 28, 2006 10:44:41 GMT -4
The following is a photo of the full Moon taken from Earth. Note that there are no stars. Taking a photo of the Moon requires exposures similar to those required to take a daylight photo on Earth. This is because both the Moon and the Earth are sunlit objects. Setting the camera exposure to record detail in a sunlit object means that extremely faint objects like stars are outside the range of what the film can record. The stars are there but they are just too faint for their images to show up on the film in the short amount of time the film was exposed. The following is again a photo of the Moon taken from Earth, but this time the Moon is a thin crescent phase. The extremely bright and over-exposed crescent along the Moon’s bottom-right edge is the sunlit part. The part of the lunar surface showing detail is the nighttime side of the Moon. The nighttime side is faintly illuminated by light reflecting of the Earth. This time a long-exposure was used to bring out detail on the nighttime side. This caused the daylight part to be grossly over-exposed into nothing but a featureless white blob. But as you can see, the exposure was long enough in this case that we can begin to record the images of stars. The nighttime side of the Moon and the stars are both faint enough that their images can be simultaneously recorded on film, but doing so means we cannot also record detail in the sunlit part. The Apollo photos were all taken in daylight and where exposed to record detail under those lighting conditions. Using these exposures, it is impossible to record stars images.
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Post by HeadLikeARock (was postbaguk) on Nov 28, 2006 10:50:54 GMT -4
gwiz that's not what I meant. I meant are there dawns like on earth where the sun decreased radiation where the astronauts landed? Lionking The moon has night and day, just like on earth. Well, not quite like on earth - a "lunar day" is approximately 29 days, not 24 hours. en.wikipedia.org/wiki/Lunar_dayThe Apollo missions were planned so that they landed early during the lunar morning. This ensured that the surface hadn't had time to heat up to it's maximum, heating effects from the sun on the astronauts (during EVA) and the LM would be reduced, and shadow lengths would assist in landing the LM by sight. (Example - Percy and Bennet keep claiming that the planned landing point for Apollo13, Frau Mauro, was in darkness. It may well have been in darkness as the Capsule approached the moon, but due to the moon's rotation they would have landed during the lunar morning - had the mission gone as planned.) So - yes there are indeed dawns on the moon. And sunsets. I'm sure they are spectacular in their own way - but not quite as spectacular as here on earth (no atmosphere!)
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Bob B.
Bob the Excel Guru?
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Post by Bob B. on Nov 28, 2006 10:59:08 GMT -4
I'm sure they are spectacular in their own way - but not quite as spectacular as here on earth (no atmosphere!) Sunrises and sunsets on Earth can certainly be breathtaking, but I'm sure the sight of the solar corona rising above the lunar horizon would be pretty awesome.
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Post by HeadLikeARock (was postbaguk) on Nov 28, 2006 11:10:58 GMT -4
I'm sure they are spectacular in their own way - but not quite as spectacular as here on earth (no atmosphere!) Sunrises and sunsets on Earth can certainly be breathtaking, but I'm sure the sight of the solar corona rising above the lunar horizon would be pretty awesome. Indeed. Who would have thought that a solar eclipse by Saturn would look this good? antwrp.gsfc.nasa.gov/apod/ap061016.htmlCheers to tofu for that one!
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