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rudeyd
2007-Jan-13, 10:41 PM
Quick Question:
When Hubble eventually becomes inoperable, what will we have in space to take true color, actual photos of celestial objects?? I'm fascinated with all of the space telescopes, but Hubble is the only one we have that takes true color photos, correct?
The infra-red ect, photos don't compare to the real-deal photos that Hubble takes. Those photos have re-captured the general public's interest in space and with out Hubble, we wouldn't realize just how cool the Universe really is!

StupendousMan
2007-Jan-13, 11:34 PM
Quick Question:
When Hubble eventually becomes inoperable, what will we have in space to take true color, actual photos of celestial objects?? I'm fascinated with all of the space telescopes, but Hubble is the only one we have that takes true color photos, correct?
The infra-red ect, photos don't compare to the real-deal photos that Hubble takes. Those photos have re-captured the general public's interest in space and with out Hubble, we wouldn't realize just how cool the Universe really is!

The James Webb Space Telescope will take many pictures in the near-infrared. They will be just as sharp as those taken by HST, and, in most cases, will show very similar features in planets, nebulae, and galaxies. I have no doubt that the STScI PR team will produce beautiful photographs using JWST data which will inspire people exactly as much as HST pictures.

Many HST pictures have been processed to produce very pretty, saturated colors, not at all like the view you would see through the eyepiece of a telescope. JWST will do the same. The great majority of people probably don't know how much processing has been done, and don't care. The pictures are pretty -- that's enough.

It puzzles me when people claim that JWST will be unable to produce the same sort of pretty pictures that HST does.

joema
2007-Jan-14, 01:30 PM
Images from the Spitzer infrared space telescope are quite colorful and beautiful: http://sscws1.ipac.caltech.edu/Imagegallery/chron.php?cat=Astronomical_Images

Yet the Spitzer main mirror is just 85 cm diameter. The JWST mirror will be 6.5 meters, over seven times as large.

It's true JWST will not match Hubble's resolution in the visual spectrum, but it will be far better than Hubble in the near and medium infrared.

Assuming the 2008 servicing mission is successful, Hubble will be significantly upgraded with all new gyros, new batteries, a new wide field camera: http://sm4.gsfc.nasa.gov/technology/sm4_wfc3.php, new Cosmic Origins Spectrograph, and hopefully repair the Space Telescope Imaging Spectrograph. Given that, Hubble should be operational until at least 2013 and possibly well beyond. It's conceivable it could remain operational until about 2015 to 2020, when atmospheric drag (which varies with solar activity) causes it to reenter.

During that period, ground-based telescopes using adaptive optics and imaging optical interferometery will continue making progress. They can already surpass Hubble in some limited areas. It's expected that eventually they will exceed Hubble's resolution over wider viewing angles and spectral ranges.

So the beautiful pictures we've seen from Hubble will keep coming. First from Hubble itself until at least 2013 and possibly much longer. Then starting about 2013 from JWST for at least five years. Eventually ground-based telescopes will give similar images to Hubble, but with even better resolution.

closetgeek
2007-Jan-14, 04:27 PM
It's funny, for Christmas...EVERYONE got me some kind of "navigate the Cosmos" kind of book. I am so far from getting to them, and I am sure the answers are in there somewhere. So I admit, I am asking this question out of sheer impatience; the coloring in the pictures are the actual colors? There is no alteration or speculation on what the colors of those photo's would be? For instance, the Pillars of Creation really would appear like that if we were to somehow place ourselves in at a distance from it, that we would be able to view the entire area?

ToSeek
2007-Jan-14, 06:29 PM
Quick Question:
When Hubble eventually becomes inoperable, what will we have in space to take true color, actual photos of celestial objects?? I'm fascinated with all of the space telescopes, but Hubble is the only one we have that takes true color photos, correct?
The infra-red ect, photos don't compare to the real-deal photos that Hubble takes. Those photos have re-captured the general public's interest in space and with out Hubble, we wouldn't realize just how cool the Universe really is!

Very few of Hubble's famous images, even though they're in visible light, are true-color. You can read about the processing of the "Pillars of Creation" image here (http://www.pbs.org/wgbh/nova/origins/hubble.html).

antoniseb
2007-Jan-14, 06:35 PM
Hubble is the only one we have that takes true color photos, correct?

Others have pointed out that the images you see from Hubble are rarely close to 'true color'. It is also worth noting that for visible light images, we now have the technology to build ground-based telescopes that produce clearer, deeper, faster images than Hubble. As the various large telescopes get built with (or retro-fitted with) adaptive optics, there are very few visible spectrum images where Hubble offers some advantage over much cheaper ground based observation.

joema
2007-Jan-15, 12:06 AM
...the coloring in the pictures are the actual colors?...the Pillars of Creation really would appear like that if we were to somehow place ourselves in at a distance from it, that we would be able to view the entire area?
It's natural and common to ask "would the object really look like that to the naked eye if I was close enough?"

The answer is frequently no. There are two issues, color and brightness, which are partially inter-related.

Consider the Andromeda galaxy, M31. It's six times the diameter of the full moon, yet unassisted, you can only see the central core as a fuzzy star on a dark night. We're already close enough that it's quite large, but you can't visually see the full extent. Your eyes just aren't sensitive enough. Not all nebulous objects are like that but many are.

Each object is different regarding how well images would reflect the visual representation at a closer distance. Some smaller objects like globular cluster M13 would probably look pretty impressive at, say, 1/100th the current distance: http://www.seds.org/messier/m/m013.html

Color is related to brightness, as the cone cells in your eyes aren't as sensitive as the black-and-white rod cells. Using a fairly large telescope visually, you may see detailed nebulae (including the Eagle nebula M16 where the "pillars of creation" image was taken). Yet visually you don't normally see the striking colors of printed photographs taken through the same telescope.

This doesn't necessarily mean the images are artificially enhanced with false color (although they can be). This issue has existed from the earliest days of color astrophotography with terrestrial telescopes. Like modern electronic imaging devices, color photographic film can better capture images of nebulae than your eye looking through the same telescope.

Kaptain K
2007-Jan-16, 10:42 PM
Diffuse objects (nebulae) will never look the same to the naked eye as they do in photographs. Take M42 for example. From Earth, 1500 light years away, it is about one square degree and magnitude +3. From 150 light years away, it would be 100 times brighter - mag -2 (about as bright as Jupiter). Impressive, right? It's also 100 times bigger (100 square degrees). So, the amount of light per cone cell is essentially unchanged.
For clusters, it's a different story. Since they are made up of individual stars, the view would get better and better the closer you get. I would love to see M13 (globular cluster in Hercules) "up close and personel"! From 250 light years away (1/100 it's distance from Earth) it would be about 30 degrees across and -6 magnitude! There would be thousands of stars visible to the naked eye, many bright enough to show colors (yellow and red).