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Old 06-March-2005, 01:38 PM
johnp johnp is offline
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Default Earth's size on the apollo photos

Hi people,

I'm new on this forum, and I came here for only one reason - there's at least one question I've never seen answered on the texts debunking the moon hoax theories point by point.

Specifically, I've never seen an explanation of why planet Earth as seen on the moon landing photos is not bigger than the moon seen from Earth. This doesn't make any sense, since that the moon is much smaller.

Some example photos:




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Old 06-March-2005, 01:47 PM
Bounced Check Bounced Check is offline
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Have you ever seen the moon in the sky without ANY frame of reference to judge the scale?

Seriously, the earth looks tiny in those pictures because of a couple of fractors, not the least of which is lack of an atmosphere and the focal length of the cameras.

Do what I did - hit a local community college and ask about a course in photography or find a locla photographers club. Learning how cameras work is a cool thing and that way you can learn for yourself why this looks like it does.

I'm expecting Jay to see this thread and I really enjoy his posts. If he doens't get to it I'll return with more.
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Old 06-March-2005, 01:48 PM
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The answer has to do with the characteristics of the camera lens.

The Moon (as seen from Earth) is actually much smaller than most people think, only 1/2 degreee of arc -- 1/360 of the full arc of sky from horizon to horizon. If you take a picture of the Moon with a standard (non-telephoto) lens, it will appear very tiny indeed.

In all the pictures of the Moon that we're used to seeing on TV and in movies, a telephoto lens is used to make it more prominent.

Combine that with the fact that the Hasselblad camera used on the Moon had a somewhat wide-angle lens, and you can see why Earth looks rather small in the Apollo photos.

Perhaps someone with more knowledge of the lens characteristics can compute exactly how much of a frame you'd expect the Earth to cover from the Moon. I doubt that there will be much difference from what we see in these shots.
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Old 06-March-2005, 01:52 PM
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By the way, the bottom two pictures in the OP are not pictures of Earth. They're lens flares.
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Old 06-March-2005, 02:03 PM
Dwight Dwight is offline
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Hi and welcome! The reason is simple: the type of lens used for surface photography (not including the closeup, stereo and 500mm lens) as follows:

Hassleblad 70mm
Superwide angle camera
38mm lens

Hasselblad 70mm
EL Data Camera
60mm lens

Both lens types are considered "wide" angle lenses (well, the 60mm is more like a standard lens). Primarily used as landscape photography lenses. Things that are far away will appear smaller than in reality. I took a photo while in Warsaw last year of the "Russian Palace of Arts" over which a beautiful and _large_ moon hung. When I looked at the photo at home, it was no where near as spectacular as what I saw with my eyes.

Furthermore, if you have the Apollo TV dvds, find the section where Ed Fendell points the LRV camera at the earth. You will definitely see a large and spectacular earth in the shot, and also a good example of what different lens specs (in this acse a zoom lens) will do to an image.

BTW I am working from rusty memory of photgraphic principles here, so if anyone could check the maths, that would be most welcome.
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Old 06-March-2005, 03:29 PM
Joe Durnavich Joe Durnavich is offline
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There is a discussion on this on BABB, including my rough calculations for the Apollo 17 photo:

Earth size thread

The first message of the thread contains links to the high resolution photo being measured.
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Old 06-March-2005, 05:38 PM
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I remember way back when doing the Chesley Bonestal sorts of figuring -- view angle of camera, size and distance of object, small angle equation to figure how much it subtended, and the nasty apparant magnitude calculations. At the time I was working towards a verbal description of mostly imagined extra-solar scenes.

(And then there's the satirical "Science Made Stupid," with its "Jupiter as seen over the left shoulder of a gerbil being blown out of a volcano on Io...")
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Old 06-March-2005, 06:41 PM
Tom Ames Tom Ames is offline
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It's worth taking a picture of the moon for yourself (without a telephoto lens).

Wait for a time when the moon is full, and looks to your eye to be huge.

On the photo it will be barely visible.
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Old 06-March-2005, 07:19 PM
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Quote:
Originally Posted by Tom Ames
It's worth taking a picture of the moon for yourself (without a telephoto lens).

Wait for a time when the moon is full, and looks to your eye to be huge.

On the photo it will be barely visible.
This is very true. When you look up at the Moon it seems large but it is really very tiny. In fact, if you hold up your hand at arms length, the apparent size of the Moon is only about half as wide as the fingernail on your pinky. Try it... you'll be surprised.
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Old 06-March-2005, 09:23 PM
johnp johnp is offline
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Thanks for all the replies

I'll give it a try at photographing the moon one of these days. Not that I doubt what you guys are saying, but it will be an interesting experiment, and digital cameras make it easy to shoot photos nowadays
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Old 07-March-2005, 01:46 AM
Bounced Check Bounced Check is offline
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Just as an side - does anyone know if a digital will capture the faint light from the moon? I've gotten two good picutres of it over the last (cough.. long time) few years and that was only thanks to having some excelent low light film and a camera that allowed me to leave the shutter open long enough to get the shot!
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Old 07-March-2005, 03:42 AM
die Nullte die Nullte is offline
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In the posted photos, the earth is not, to my eyes, notably small, and I can assure johnp that the moon, photographed from the earth with this same equipment, would look tiny. If you've done any traveling and have taken pictures, consider that the average person who takes a snapshot of something enormous like, say, the Grand Canyon or an imposing mountain, often finds the subject to be disappointingly puny in the photo. The interpretation of a distant object as "big" is a trick of the brain, and it can be quite difficult to capture the object's perceived size on a two-dimensional photograph. Experience, a careful choice of equipment, and a certain artistic sensibility are often required to make a big object look big in a photo.
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Old 07-March-2005, 04:22 AM
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The Bad Astronomer The Bad Astronomer is offline
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I too will iterate this. The Moon is very, very small, especially in photos. A lot of beginning photographers are disappointed when trying to get picture of it (that included me, a while back). The Moon is about 1/2 - 1/3 the diameter of your thumb when your hand is outstretched. Try it the next time the Moon is up. You'll be shocked.
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Old 07-March-2005, 05:51 AM
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Quote:
Originally Posted by Bounced Check
does anyone know if a digital will capture the faint light from the moon?
Yes.

I've taken plenty of pictures of the moon with a digital camera, if I remember correctly I usually had my shutter speed set to 1/30, automatic exposure settings didn't work very well when taking pictures during the night, or in low light.
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Old 07-March-2005, 06:11 AM
Grogs1 Grogs1 is offline
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It should be possible to take a photo with, say, a 500mm lens from 50m away and another photo with a 50mm lens from 5m away and get virtually the same *foreground* image, i.e., astronauts, LM, lunar surface, etc. Objects at infinity (so far away that the light essentially comes in on parallel lines) will appear much larger on the first photo because moving forward 45 meters doesn't really get you close to them like it does with foreground subjects.
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Old 07-March-2005, 09:14 AM
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So then, were the famous earthrise pictures taken with a telephoto lens? (Also, weren't they [earthrise pics] frames from a 16mm motion picture?)
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Old 07-March-2005, 01:12 PM
Tom Ames Tom Ames is offline
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This site says that the famous photo was taken by Bill Anders on Apollo 8 using a 270mm lens on a Hasselblad body.

Note that a frame from a 16mm movie could sill have been taken through a telephoto lens.
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Old 07-March-2005, 01:33 PM
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Quote:
Originally Posted by mathyou9
So then, were the famous earthrise pictures taken with a telephoto lens? (Also, weren't they [earthrise pics] frames from a 16mm motion picture?)
One HB tried to use the Apollo 11 earthrise photos (AS11-44-6549) as evidence of fakery, based on that the earth looked much bigger in them than in the photos taken from the surface.
The lack of reseau grid in the earth rise photos should be the first hint to point out that they were taken with a different camera. ALSJ Apollo 11 Photography Reference says that the photos in Magazine V were taken with a 70-mm Hasselblad Electric Camera in the command module.
The lens used to take those particular earthrise pics was 250mm.

That's easy to check: The earth's diameter in the photo I linked above is about 135 pixels. The width of the picture 900 pixels
900/135=6.67
Earth's angular diameter 1.9 degrees
The angular width of the picture:
1.9 degrees*6.67=12.67 degrees
That's pretty close to the indicated Field of View 12.5 degrees with 250mm lens.

I believe there are famous earthrise picture from Apollo 8 mission but I haven't looked them up so I don't know what camera was used to take them.
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Old 07-March-2005, 01:40 PM
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Most people don't know what the moon looks like, let alone it's size.
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Old 07-March-2005, 01:56 PM
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Quote:
Originally Posted by Bounced Check
Just as an side - does anyone know if a digital will capture the faint light from the moon?
Easily. There is a piece of equipment a lot of pros use called a Kodak Grey Card, which is used for calibrating exposures in difficult lighting conditions outdoors. It reflects 18% of the light which falls on it, exactly the same as a scene in full sunlight. The Moon's surface reflects about 17%, so it's almost a perfect grey card illuminated by full sunlight. So for a full moon just use the same exposure you would use for a family picnic.

Well, not one of my family picnics, it always rains for those...
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Old 07-March-2005, 01:57 PM
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Two facts about observing the moon from Earth tend to shock people: the moon subtends an arc of only about half a degree (most people would guess several degrees), and the moon and the sun subtend about the same angle -- half a degree (most people say the sun is bigger).

Photographing astronomical objects with ordinary cameras is notoriously difficult. I work near Point of the Mountain in Utah, which is one of the best hang-gliding and paragliding sites in the U.S. One evening as I left work, I noticed the line of site to the moon was through the squadron of hang gliders so that they appeared to be flying around the moon. The only camera I had with me at the time had a limited zoom lens, and so I was not able to get a good photo.

The corollary to the argument that the stars should have shown up in Apollo photograph, is the argument that the stars and other objects should have been so breathtaking and brilliant that the astronauts would have tried at least once to get them on film. But the equipment they had for still photos is just all wrong to do that.
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