ELI5 why we do not see any stars in these images from space.

9  2016-01-15 by Putin_loves_cats

41 comments

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Thanks. looking at some now.

Our eyes see differently than cameras. Light surrounding and reflecting off the surface wouldn't let the stars show as well. Usually those amazing space photos from the Hubble are super long exposures. They also add color to highlight the stars better. Alot of What Is represented is artifically represented from an absorption spectrum. Like the color of the sun being "yellow". It's true light is incredibly brilliant but it falls in the yellow of the visible spectrum.

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Because at night there isn't enough background light radiating that outshine the stars. If you live in a city, go downtown and take a pic. You won't be able to see any stars because of all of the other lights drowning out the weak light of stars.

Go to a darker place and then you can see the stars.

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The light blasting down on the moon directly from the sun, like our own daylight, is too bright to see stars on that part of the moon, yes. Its very simple. Like I said earlier. If we had no atmosphere then our sky would be black in the daytime too except for the sun.

Why wouldn't they develop a special camera for this reason though? I mean think about it. This was the most monumental feat/event in human history. It doesn't make sense.

Well there's a few reasons. First would be that they had a limited amount of time to be there for starters. Their focus would be on the moon, not pics of the moon. Remember that the light side of the moon is always lit. So it's not like they could wait until nighttime to take pics of the sky. You dont see stars in the daytime here on earth. Without anatmosphere our sky would be black in the daytime too except for the brilliant ball of light called the sun. The other issue is where to focus the camera. You know that photo of the earth from space? You don't see stars in that photo because the focus is the earth. The periphery doesn't provide enough light. Not to patronize but stars are sooo far away that their light is very weak. We didn't exactly have the technology to take nice photos then either. The Hubble wasn't around yet.

Even if you argue that we could go to the moon but didn't have sophisticated camera technology. All technology doesn't evolve together. Did you read that post on how complicated and crazy cathod tvs were compared to the simple LED technology of today? Humans often invent backwards.

Remember that the light side of the moon is always lit.

That is pure bullshit.

There is no "light side" of the moon. When the moon is between earth and the sun, the far side is lit. When the earth is between the moon and the sun the near side is lit. No part of the moon is permanently lit or permanently dark.

Fine. Whatever. Where they landed, they were in the sunlight. Which made it too bright to see stars.

The scattering of light in the earth's atmosphere is what prevents us from seeing stars in the daytime. If there were no atmosphere, and hence no scattered light, you should be able to look straight up at twelve noon and block the sun with your hand and see stars. No light scattering = nothing competing with the brightness of the stars

Right. But on the moon the surface is so reflective, as you see at night, that it drowns out the star light. Even at night on earth if you just snap a picture outside with you as the focus you won't see stars. You need darkness, long exposure, and a wide lens to focus on the sky. If we had no atmosphere the earth itself would absorb some light making it easier to see but the sun is so bright you wouldn't see starlight anyway.

Try it yourself. Go outside with a camera and take a pic of a friend. You're not gonna see stars in your pic. Look up what light polution is.

Back to the point on hand, the ambient light reflecting off the moon surface would make it very hard to see any stars if at all. It's akin to stargazing in the daytime.

Right. But on the moon the surface is so reflective, as you see at night, that it drowns out the star light.

I think your missing the point. It will only drown out the star light if you look at the moon. If you are on the moon and look up, none of the light bouncing off of the surface of the moon will be entering your retina_because there is no atmosphere to reflect it back down into your eyes. So long as you block the sun and the refection from earth from shining in your eyes, you should see stars, even if the sun is directly overhead. It is only the light entering your retina that matters here, not what reflects of the surface of the moon.

Even at night on earth if you just snap a picture outside with you as the focus you won't see stars.

Of course not, the reflection from the flash is entering your retina and competing with starlight.

You need darkness, long exposure, and a wide lens to focus on the sky. If we had no atmosphere the earth itself would absorb some light making it easier to see but the sun is so bright you wouldn't see starlight anyway.

The sun would be like a laser beam without atmosphere. You could literally block it with your first and no light from the sun would enter your retina, then you would see stars.

Try it yourself. Go outside with a camera and take a pic of a friend. You're not gonna see stars in your pic. Look up what light polution is.

Yes, the reflected light competes with start light.

Back to the point on hand, the ambient light reflecting off the moon surface would make it very hard to see any stars if at all. It's akin to stargazing in the daytime.

There is no ambient light without an atmosphere.

Check out the link I sent you. Cameras, even in space are geared towards the weak light coming from the stars. It explains what I'd been saying but it probably explains it better than I. I tend to ramble. This isn't about your eyes on the moon. It's about the camera. The camera wouldn't be able to take a photo even if pointed right at them.

The Hubble doesn't take pics in the direction of the sun. It's just too blinding. But don't believe me, call 212-769-5901. That's Neil deGrasse Tyson's phone number at the Hayden planetarium. He may not answer but the number is available for general questions.

I understand quite well already. I was just correcting a common mistake that people make. That mistake is simply believing ambient light exists in a vacuum.

It doesn't. You can block the sun out with a disc of the right diameter and quite easily photograph stars that are even behind the sun (light bends due to the suns gravity). There is no day in space, only night. And there is no sun, just a close star.

Peace my friend.

Yeah but when light hits and object and reflects from it, it scatters. Like the light hitting the moon.

War and famine to you and your people.

Yes, and if your standing on the surface of the moon looking up, do you think any of those scattered rays will enter your retina? Or a camera lens?

LOL YES.

But actually just for fun let's actually call that phone number I left. Like tomorrow or Monday? See what they say. It should be fun! Besides no one else but you and I are still reading this thread anyway.

It's not necessary. Let me give you a quick basic physics lesson. When light reflects off of any surface, it continues in the direction indicated by that angle of reflective incidence until it strikes another object. If you are on the surface of the moon, looking up, that light is not going to magically curve around after it passes you and strike your retina. It will just pass you by, invisibly and without interfering with your vision of the stars.

Basic geometry my friend.

If there were no atmosphere, and hence no scattered light, you should be able to look straight up at twelve noon and block the sun with your hand and see stars. No light scattering = nothing competing with the brightness of the stars

This isn't true and is easily testable. Imagine having one of those bright photography spot lights in your face. Something strong enough to illuminate a whole room really well. You're not going to be able to see other normal light bulbs in the room. Especially the further away they are. The closest star is thousands of years away even when traveling at the speed of light.

Front screen projection. http://i.imgur.com/Mh2an.gif

Stereoscopic parallax also proves the photos are fake: http://www.aulis.com/stereoparallax.htm

Numbers 1,2 & 3 might have been photographed in a studio
Number 4 is a blatant composite.

If 1,2 & 3 really were shot on the moon, the excuse given by NASA fans is that that a combination of the aperture settings (the opening to the lens is too small) and shutter settings (not enough light enters lens) are the cause that no stars to appear.

If I to played along with the silly notion (in my opinion) we went to the moon, I'd continue to explain that on the moon, the sun and reflection of the sun on the surface of the moon does not require much light to expose the astronauts, surface, & LEM. If enough light is allowed to enter the lens during a single shot which were to display the stars, nothing else would be discernible (it would appear as a bright over-exposed white)

The reason I hate this as an excuse is that I wonder, oh indeed I wonder, why engineers didn't prepare a camera setting ( or even a camera for this specific purpose!) which was meant to photograph what should be one of the most brilliant star scenery a man or woman has ever seen. It blows my mind. It's so blown that I don't believe we landed on the moon (one of many reasons)

I made this comment before but I'm interested what is your take; While watching a documentary on Everest a few years ago they mention a common mistake climbers make is taking their sunglasses off at the summit. They end up with sunburnt eyes and can't see well enough to make it back down the mountain. If the sun is that bright at the top of Everest, how could it not be blinding in the surface of the moon? No atmosphere - and there are pictures if astronauts with the visor up in the sunlight. This doesn't add up...

Good point. Most of the pictures I've analyzed seem to have visors down. And even if their visors are up I'd assume they have some sort of UV filter (which are usually considered to be the damaging wavelengths to our eyes)

Our eyes are stronger than one normally thinks due to the precautions suggested to us as children. You can stare directly at the sun at the sunrise or sunset very comfortably. You should try it sometime; it feels very nice.

That being said, high intensity long duration sun exposure is bound to cause damage or blindness. If I were to believe in the moon landing, I'd suggest that the pictures you've seen with visors down are close to sunrise or sunset on moon (I believe sunrise.) On moon there will be no special colors or prettiness associated with sunrise or sunset and you'd have to tell by the direction of shadows. (Another clusterfuck to analyze with any precision due to "undetectable curving foreground."

BUT the reason I suggest this isn't because I'm making a parallel between staring at the sun during sunrise on earth, which is only possible due to thick atmosphere. It's because during sunrise, the reflected rays off the moon's surface are (mostly) directed in a predictable way due to geometrical/mathematical analysis of incident waves. So If I were to examine a picture of an astronaut with a visor down, I'd assume the sun is directly (or near directly) behind him, which would suggest that negligible reflected rays are making their way to the retina. If the sun was directly overhead there is a much more even dispersal of reflected rays off the moon's surface, and I'd assume visors always need to be down.

If this explanation isn't clear enough I can try to clarify more. Let me know. Also if you could post the picture that piqued your interest I'd appreciate it! If the sun is in a discernible location which would cause this argument not to apply, it becomes highly suspicious in my eyes (pun intended)

Thanks for the comment. Yea, I agree. That view of the universe should be mind blowing. Stars, far off constellations, etc etc. I mean shit, go out into areas without light pollution and look up at the sky. It's unbelievable. Example

No problem. I assume you just want to talk about the supposed moon landing or you really weren't show of the reason?

The types of photos as seen in that example probably have +5 second shutter time. I've taken some brilliantly pictures with 20 seconds of exposure. On this note, the same could be done with a special camera during one of 6 times we supposedly landed on the moon in a 4 year period (never to return 'since 1972')

I think they're both intertwined. I'm not 100% convince we did go to the moon and this OP was more about the technical reasons why we don't see stars. I agree, I mean, they could've developed a special camera for this EPIC moment in human history, to show the glorious universe. I find it hard to believe (as you said) they didn't. Doesn't make sense.

They decided to bring a moon buggy instead. Oh well.

Put a dash-cam on that bitch, lol.

I agree. I've been to an observatory which was merely at high altitude but away from light pollution and the number of stars that can be seen is life-changing. It so dense it's unbelievable for city-dwellers.

Two reasons: Hard to fake in a studio or too hard to check for anomalous objects. The 2nd is extremely likely as NASA photos are edited heavily when there is sky/space involved. Go look at some and you can see all the little artifacts that were missed.

And when it's night time, how brightly lit is the ground around the observatory?

It's not, is it? In fact it's pitch black.

In daylight, when you can see the ground around the observatory brilliantly lit, can you see the stars? No.

Before feigning precociousness, remember that some of the missions spanned multiple days and multiple moonwalks. Doesn't that mean they were there for a lunar night or at least lunar dusk? (Albeit within the confines of the LEM?)

One lunar day is 28.5 earth days long, no they didn't stay the night.

Great point. My mistake. If they didn't stay the night, (assuming they were there during the day) have you come across any thermal analysis on how they kept the ship (and humans) from overheating? Lunar days are quite radiative from what I understand.

Perhaps they were only there during the sunset or sunrise which would mean slight illumination but not a time of maximum radiation? But then the same argument can be applied; at dusk and dawn, in an atmosphere-less environment, I'd expect the (brightest) stars or planets to at least be somewhat visible if pointing the camera or your eyeballs opposite the direction of the sun (not substantiated, but if we take the moon photos as real, my expectation is incorrect.) The reason my skepticism continues is that I know some planets can be seen in daylight on earth, even through such a thick, optically dispersing, turbulent atmosphere.

Because the realistic moon set I visited at Cape Canaveral, before the Apollo missions had no stars on its black wall.

Apparently, the astronauts didn't see any stars at all. They didn't see stars...http://youtu.be/hh0y6xPZJhc

Same reason you can't see stars on Earth during the day. The Sun is too bright.