We’ve all seen these fantastic Hubble telescope images (www.hubblesite.org/gallery/album/ for instance) and what I’m wondering is, if I was up there in a space ship and saw these planets, or galaxies, or nebulas with my own eyes - would it look like those pictures? With all those colors and everything?
No. They typically enhance the images to increase the contrast and color saturation and in some instances change the color so they’re more photogenic.
That’s what I figured. Thanks.
Makes one curious how it would really look to one’s eyes.
Plus the objects being imaged are too dim to be seen with the naked eye, even though they are very big. For example, in our own sky we can see the Andromeda galaxy as a faint smudge if we look in the right place in a very dark sky. But it’s actually a very big object; several times larger than the moon in fact. If our eyes were about a bajillion times more sensitive, we could see something like this composite image.
And for another example, with better eyes (or a good telescope, camera, and looong exposure time) we could see nebulas like this in our very own sky.
For Hubble images, typically, they’re also imaging frequencies of light that we cannot see. So to make the composite image, they might combine a far-infrared image as “red”, near-infrared as “yellow”, visible light as “green”, and UV light as “blue”. Other telescopes can see other parts of the spectrum, so sometimes they’ll add x-ray or microwave images to the composite as well. The result is a scientifically accurate image, but it does involve a fair amount of artistry and somewhat arbitrary choices to produce something aesthetically appealing.
So one could say that in principle (even the colors aside) you would never actually see such fantastic views when looking out of your far reaching space craft?
Probably not, unless perhaps you were very close to a particularly spectacular object.
The Hubble site has more on how they make their composites here.
Many thanks.
And even then, you probably wouldn’t. Astronomers use a lot of false color, combine images from different wavebands that your eye doesn’t have a hope in hell of detecting, we apply smoothing to images and generally do a lot of image manipulation to end up with those final “publicity” images. In many cases, these are practically impossible to do any real science with – they just look good and are used to sell the science to the public, and look good in publications etc.
Here are some fairly recent threads on related issues
I’ts not that these objects are not real, human eyes just can not detect them.
The Trifid nebula provides examples of “publicity” style images ranging from sedate to garish:
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Some images need to be reproduced on black velvet, and hung behind the sofa:
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What you would see from space isn’t really any different from what you can see on a nice, clear night away from cities here on Earth. Which is pretty spectacular: You owe it to yourself to go stargazing someplace dark, if you’ve never done it before. But you won’t see color for most things, and most things the Hubble observes you won’t see with the naked eye at all.
This site gives a good example of what differing ‘frequencies’ reveal and how our eyes are pretty limited in seeing what is up there.
Wow! Thanks for the link. When I was at a dark sky site at the proper time of the yer (late summer) I deliberately sought out M31 since it is the most distant object the Mk I eyeball can see. I had no idea I was seeing only a small (brightest) part of the thing.
Yeah, I was pretty amazed when I found out about that. I did try to find it once with a telescope, but all I ould make out was a faint smudge, and that was only if I didn’t look directly at it.
That was in the city.
Oh, yeah. I forgot to ask but it’s been on my mind. I’ve noticed when seeing Sirius twinkle, it’s the only star I’ve noticed with flashes of color in it’s scintillations. I’m not talking about stars that are normally colored all of the time like Betelgeuse but rather a nominally blue-white star showing red or green or yellow for just an instant. I’m figuring it’s the only star bright enough that the flashes tickle the cones in my retina hard enough. Any thoughts?
I think that all stars twinkle with color, but Sirius is so freakin’ bright that you just notice it more.
And for some reason, planets don’t twinkle.
Planets are close enough that you see them as discs. Stars, on the other hand, are so far away that they are just pinpoints of light, and their appearance is therefore more “fragile” — subject to whatever air disturbances are going on along the line of sight.