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| leohopkins |
 Posted: Tue Jan 09, 2007 5:19 pm Post subject: Moon landing photo's |
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Forum Professor
Joined: 10 Dec 2006
Posts: 1162
Location: Croydon, England
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How come there are no stars visible on the photo of NASA's moon landings ?
I would have thought they would have been a lot more visible seeing as there is no atmosphere ?
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| william |
| Posted: Tue Jan 09, 2007 6:56 pm Post subject: Re: Moon landing photo's |
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Forum Ph.D.
Joined: 23 Jun 2006
Posts: 910
Location: USA
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| leohopkins wrote: |
How come there are no stars visible on the photo of NASA's moon landings ?
I would have thought they would have been a lot more visible seeing as there is no atmosphere ? |
Earth has an atmosphere, yet we still see stars at night. But let me ask you a question and see if you can answer your original question from this;
where would you see more stars in the night sky here on Earth, looking at the sky from within a city, or looking at the sky from an isolated desert spot? When you have an answer, ask yourself why one is better than the other.
Or... here is a related question; why can't we see stars during the day? (Hint: It's not entirely the atmosphere's fault....)
Cheers,
william
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| leohopkins |
| Posted: Wed Jan 10, 2007 2:12 am Post subject: Dark side of the moon |
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Forum Professor
Joined: 10 Dec 2006
Posts: 1162
Location: Croydon, England
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Oh I see, so if they were taken on the dark side of the moon; stars WOULD have been visible ?
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The hand of time rested on the half-hour mark, and all along that old front line of the English there came a whistling and a crying. The men of the first wave climbed up the parapets, in tumult, darkness, and the presence of death, and having done with all pleasant things, advanced across No Man's Land to begin the Battle of the Somme. - Poet John Masefield.
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| captaincaveman |
| Posted: Wed Jan 10, 2007 11:05 am Post subject: |
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Joined: 31 Jul 2006
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from what i read somewhere, the reasons stars are not visible is something to do with camera settings, they had to crank it down a bit
could be wrong though
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| Guest |
| Posted: Wed Jan 10, 2007 11:28 am Post subject: |
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Stand in a well lit room - go straight outside and see if you can see stars, your eye dilates to let more light in - same on the moon with a camera, it is set to the average light from the ground - if you opened it up to see the stars, the foreground would be over exposed.
Also look at how pale the moon is when the sun is up, then how bright it is at night. |
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| weknowtheword |
| Posted: Fri Mar 02, 2007 5:38 am Post subject: |
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| Reidar |
| Posted: Sun May 06, 2007 5:27 pm Post subject: |
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Joined: 15 Mar 2007
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"Pretend for a moment you are an astronaut on the surface of the Moon. You want to take a picture of your fellow space traveler. The Sun is low off the horizon, since all the lunar landings were done at local morning. How do you set your camera? The lunar landscape is brightly lit by the Sun, of course, and your friend is wearing a white spacesuit also brilliantly lit by the Sun. To take a picture of a bright object with a bright background, you need to set the exposure time to be fast, and close down the aperture setting too; that's like the pupil in your eye constricting to let less light in when you walk outside on a sunny day.
So the picture you take is set for bright objects. Stars are faint objects! In the fast exposure, they simply do not have time to register on the film. It has nothing to do with the sky being black or the lack of air, it's just a matter of exposure time. If you were to go outside here on Earth on the darkest night imaginable and take a picture with the exact same camera settings the astronauts used, you won't see any stars!"
http://www.badastronomy.com/bad/tv/foxapollo.html#starshttp://www.badastronomy.com/bad/tv/foxapollo.html#stars |
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| Elina |
| Posted: Mon May 07, 2007 7:24 am Post subject: |
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Forum Sophomore
Joined: 10 Aug 2006
Posts: 110
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| weknowtheword wrote: |
| moon is made of helium gas |
Oh, really?
And why do you think so? |
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| Frozenoak |
| Posted: Mon May 07, 2007 5:51 pm Post subject: Re: Dark side of the moon |
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Forum Freshman
Joined: 04 May 2007
Posts: 12
Location: Orange Co. California
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| leohopkins wrote: |
| Oh I see, so if they were taken on the dark side of the moon; stars WOULD have been visible ? |
simply put: Yes. |
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| musicalaviator |
| Posted: Thu May 10, 2007 6:32 pm Post subject: |
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Joined: 17 Oct 2006
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More to the point. With objects such as the Ground visible in the physical astronauts eyesight within 8 minutes previous, even the Astronauts shouldn't have been able to see stars due to the pupils in their eye contacting to regulate light-flow so as not to pain their retinas. My Bedroom has a window which faces the rising sun during Winter, and I have some very good shades on the windows so that my room is still dark in the mornings. When I wake up I can see my black socks in my drawer which is always in shade due to it's placement relitave to the window. When I open the blind and get a face full of sun, my eyes hurt for a few minutes while they adjust to the wildly increased light. Soon they stop hurting and I can look out the window at the street below, but when i go to put my socks on I have to feel around because I can't see a darn thing in there.
At Night with my desk lamp on, I can see my socks just fine.
To see some of these concepts in action with a Camera, take a look at this video:
http://www.youtube.com/watch?v=tEizr7pr1Kc
In the first few seconds you can see easily the Pilots Hand on the Controll stick and a few instruments, Then when the view pans further up the camera apeture reduces to let in less light so that the view out the window becomes less overexposed. Suddenly the pilots hand and all the control instruments fade into darkness.
Apply this to the Moon landings now: Although the Sky is Black, it is not Night time! It is infact day time, and the light coming from the sun is every bit as bright as it is here on earth, if not brighter. The only difference is there is no air to scatter the light around the sky, so the only thing reflecting light is surfaces like Ground, People, Spacecraft... |
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| MikeDev |
| Posted: Tue Apr 15, 2008 6:33 pm Post subject: |
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Joined: 05 Apr 2008
Posts: 7
Location: Los Angeles
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thats cool so then when the took pictures of the earth from the moon why does only part of the earth is seen
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| Ophiolite |
| Posted: Wed Apr 16, 2008 1:22 am Post subject: |
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Forum Radioactive Isotope
Joined: 25 Jul 2005
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Location: Scotland
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| MikeDev wrote: |
| thats cool so then when the took pictures of the earth from the moon why does only part of the earth is seen |
Because that is the part that is facing the sun.
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| BumFluff |
| Posted: Wed Apr 16, 2008 3:26 am Post subject: |
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Forum Senior
Joined: 06 Mar 2008
Posts: 378
Location: Canada
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yeah. The sunlight on the moon would be overpowering for the camera so they needed to tone down the brightness quite a bit on the camera. So much that the stars aren't visible.
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| UKDutyPaid |
| Posted: Wed Apr 16, 2008 9:38 am Post subject: |
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Joined: 13 Nov 2007
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| weknowtheword wrote: |
| actually nasa's r fooling us. they had landed on some another planet instead of moon. proof.. moon is made of helium gas, how can one hop(jump) on gas or land spaceship!!! |
lol, I'm not sure which part of your post to correct first... |
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| kojax |
| Posted: Sun Apr 20, 2008 3:59 am Post subject: |
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Forum Ph.D.
Joined: 27 Mar 2007
Posts: 949
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| BumFluff wrote: |
| yeah. The sunlight on the moon would be overpowering for the camera so they needed to tone down the brightness quite a bit on the camera. So much that the stars aren't visible. |
I would believe this explanation the most. The moon is a very bright object. It's white, and gets hit by sunlight that hasn't had to pass through an atmosphere.
I'm betting that, if they didn't deliberately dim their camera quite a lot, all we'd be seeing when they pointed it at the moon is a white blurr. |
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