Part of me always hates telling people this, because so many people find the space photos taken by Hubble, Spitzer, Chandra, and other space telescopes to be so inspiring. But here goes...
The beautiful colors in NASA space photos are not real. They are not what the telescope sees, nor are they what the objects would look like if you could somehow get closer to them. The photos are created by overlaying images taken at several different wavelengths and applying color filters to each image. The resulting mix of colors creates the beautiful results we see in the newspaper, on the front of National Geographic, etc. Chandra, for instance, does not even record light at wavelengths that human eyes can see, so these photos are especially arbitrary.
HOWEVER, this does in no way take away from their power! The real beauty of these images is that they allow us to visualize objects whose size and scale otherwise boggle our minds. They serve as stunning visuals that our little planet is by no means the only interesting object floating around in outer space. When these images are taken by the telescopes, they are done so in a way that interesting features are made prominent, so that they can be studied further. The images are made to show the science behind them.
Now to the best part... The image masters at the Space Telescope Science Institute (where they run the Hubble space telescope) have developed a Photoshop plug-in that allows anyone to create their own NASA space photos! All you need is a copy of Photoshop and some patience. The plug-in, called FITS Liberator, allows you to import astronomy image files (FITS files) into Photoshop so that they can be edited. FITS files can be download from several rather hard to find sites, and I have compiled a list of some good ones at the end of this post. Just follow the directions here (or here) to get started. As the creators describe, there are several methods to choosing the color filters for each exposure. You can order them from blue to red in a natural way that would try to mimic what the objects may actually look like if we could see them up close, or you can choose hues arbitrarily. The FITS Liberator site even includes a Photoshop action to make the process simpler. I find that the real trick is fiddling with the hues of each layer so that all layers combine to give pleasing colors.
The images here are some that I've made with public astronomy data files. The first one, supernova remnant N49, is a composite of data from Chandra x-ray data (red/purple), Hubble optical data (blue), and Spitzer infrared data (yellow). The next one is the heart of galaxy M82, with the spewing red filaments showing the H-alpha emission. Below are two versions of Sagittarius A, the supermassive black hole at the center of the Milky Way. And finally, at the bottom is a landscape-looking crop of Jupiter's cloud system.
Here's a list of sites where you can download clean FITS files of pretty astronomical objects:
ESO Education Datasets (a good place to start)
Hubble M82
Hubble M51
Hubble Ultra Deep Field
Hubble Helix
Hubble - four planetary nebulae
Comments