Real Color Images?

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RachaelWhitney

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I have a question for all of you smart people :)

Why dont we have a telescope in space that takes real color photos? I understand how the hubble works and all, but why cant it take real color photos so why can see what everything would look like if we were to see it with our real eyes? I am very sure that everything going on up there isnt as colorful as these pictures make them out to be.......I sure do wish they were though, they are so beautiful.
 
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ramparts

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Good question! Anyone who's more familiar with observational astro can feel free to chime in (I've only dabbled), but essentially it's more scientifically useful to do things the way they're done now, with measurements taken in a small number of specific colors.

So the thing with Hubble is that while it's obviously taken beautiful pictures, and done some tremendous work in getting people interested in science (and astronomers love the Hubble photos more than anyone!), it's primarily a science mission. It's a very, very expensive machine, and the taxpayers shouldn't be footing the bill for a giant digital camera ;) So it's the science goals that come first.

As it turns out, it's far more useful for scientific purposes to know how much light an object gives off at a few key wavelengths (colors), rather than knowing what a full-color image might look like. If you were to read through some modern astronomical papers, you'd see pretty common use of things like "B-I" and "U-B" and other "colors" - differences between how bright an object is in two different color ranges. This can tell us all sorts of things about what kind of object something is, where a galaxy is forming stars, what phase of its life a star is in, etc. This is why you'll see, for example, lots of "false-color" images of galaxies which have captions like "the blue shows where stars are forming", etc. - that's much easier for us to tell by looking at individual colors!

Finally, our "false-color" images, believe it or not, do a pretty decent job of reproducing what you'd see with the naked eye, particularly on optical telescopes (telescopes looking at visible light) like Hubble.
 
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MeteorWayne

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Particularly earlier in it's life IIRC Hubble did take more "real" color images. But as ramparts said, after a while as instruments were replaced, it was far more scientifically valuable to extend the observable wavelengths into the ultraviolet and the infrared. There's much more to be learned about the Universe.

While the Hubble makes pretty pictures, that is not it's primary goal...that goal is to do good science and learn as much as we can.

If you want "real" pretty pictures at "eye" visible wavelengths, they can be done almost as well from the surface of the earth. The benefit of the Hubble is that allows us to examine parts of the electromagnetic spectrum that we can't see from the surface.

Wayne

PS Good question, and welcome to Space.com!
 
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ramparts

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The one thing I'm curious about is if there's a particular advantage to using filters over getting full spectra and just determining whichever colors you want from those. It doesn't seem obvious to me that you'd get, say, better resolution by using a particular filter.
 
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dragon04

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Have you ever seen those Infomercials for the "HD Sungleasses"? Basically, they're a UV filter that makes things look "better". That's a real loose analogy, but I don't know if you've ever taken photographs with and without UV filters on your camera. Or even if you own a 35mm "mechanical camera".

I don't know that it's so much resolution as it is the general "temperature" of the colors in an image. I'm not terribly adept at explaining optics, as you can see. I just used to take lots of pictures with my Canon AE-1 and had various and sundry filters for my lenses.
 
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BuzzLY

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In many cases true color would look blank to us. Our eyes only work in certain wavelengths but there is very interesting science in other wavelenths. So if we have IR images or lower frequencies, or UV images or higher frequencies, that must be artificially turned into something our eyes can see. There are true color images but they miss a lot. Spacecraft like Spitzer and Chandra each work in wavelenghts and energies that don't register in the human eye ... all their images must be converted into something we can look at (false color) or you get .... you get nothing.
 
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kg

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Is there any information the human eye can pick up from seeing the entire visible spectrum that we don't get when we look a picture that is taken in a few wavelengths then processed into a color picture?
 
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RachaelWhitney

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BuzzLY":17izw0d6 said:
In many cases true color would look blank to us. Our eyes only work in certain wavelengths but there is very interesting science in other wavelenths. So if we have IR images or lower frequencies, or UV images or higher frequencies, that must be artificially turned into something our eyes can see. There are true color images but they miss a lot. Spacecraft like Spitzer and Chandra each work in wavelenghts and energies that don't register in the human eye ... all their images must be converted into something we can look at (false color) or you get .... you get nothing.


so lets say we were up there, flying through space......does that mean we can see anything? it just looks black? i dont think i would go as far as to say we wouldnt see anything, thats absurd!
 
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RachaelWhitney

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another question to go along with the real color photos.......why not a video camera of some sort to see if we can see anything moving? infrared video camera? or even a regular video camera, i would like to see the planets move, even see if you can get close enough to see saturns rings move CLEARLY.
 
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crazyeddie

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RachaelWhitney":27uj7qeq said:
so lets say we were up there, flying through space......does that mean we can see anything? it just looks black? i dont think i would go as far as to say we wouldnt see anything, thats absurd!
Oh, you'd see nebula, all right.....but it would look remarkably dull. You eye simply does not collect much light, and it is most sensitive to the green wavelengths of visible light (which is no coincidence.....that's the wavelengths the sun radiates most strongly in). So if you were looking out the window of a spaceship in orbit and saw the Great Orion Nebula, perhaps using a set of binoculars, it would look a rather palish blue/green.....nothing like the spectacular photos you see in magazines or on the web, all of which are time exposures. Kind of disappointing, I know.....but oh, well! We can't always have the universe we want!
 
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ramparts

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RachaelWhitney":uiplit1u said:
so lets say we were up there, flying through space......does that mean we can see anything? it just looks black? i dont think i would go as far as to say we wouldnt see anything, thats absurd!
No no no! :) I'm not entirely sure what BuzzLY meant but you will certainly see things with the human eye in space. What you would miss are many interesting phenomena hidden to our eyes that are visible in other wavelength régimes.

RachaelWhitney":uiplit1u said:
another question to go along with the real color photos.......why not a video camera of some sort to see if we can see anything moving? infrared video camera? or even a regular video camera, i would like to see the planets move, even see if you can get close enough to see saturns rings move CLEARLY.
Because with a video camera, you'd need to wait a VERY long time to see things move! People do make videos from images taken a few hours/days/years apart, but almost nothing in astronomy happens on the time scales of a few seconds, say, that we'd see with an actual video camera (if you Google the name Andrea Ghez you'll see some absolutely stunning videos like this of stars moving around the black hole in the center of our galaxy). And if you think about it, a video camera is just a camera that takes very rapid pictures - usually about 30 per second. That makes sense given how fast things happen on Earth. But in space, everything is just so much...well... bigger!
 
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neilsox

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Human eye balls perceive colors differently, so a close match, is only possible for one person at a time. Also the steps between the light gathering and your brain modify the colors at least a bit. You have likely noticed colors change significantly from one computer monitor (or TV) to another. Printed on paper also involves some compromises to keep the cost within reason. Most monitors and TVs have controls that allow you to tweak the color to your taste, but none of these possibilities are exactly correct. Contrast is adjustable. Color saturation is adjustable, and can be made different = nonlinear for intense colors compared to pastels. Brightness and the transition to black is also adjustable. The percentage of red, green and blue can also be skewed, and more colors could be transmitted, but typically are not, other than colors outside the visable spectrum. Neil
 
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matthewota

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I took a full semester class in Color Theory in college, at only one of the two universities in the country that teach it. I learned that color is very subjective, and is not an exact science (That is why the class was called Color Theory. Color is in the eye of the beholder. A person with color blindness had better reception of blue light, so sees the world more sharply, albeit with the wrong colors.

There is no known camera that duplicates the reception of the human eye. As the previous poster stated, the human eye is most receptive to green, as our eyes evolved under the light of the Sun, which is strongest in the green portion of the spectrum.

I recommend that you study the physiology of the human eye more, it is quite fascinating. Read about the difference between rod and cone cell receptors.

It is also fascinating to learn how the human eye perceives color, because it changes with age and in context with other colors.
 
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