If you have some time to kill, but want to spend it doing something truly worthwhile, spacetelescope.org has just the thing for you. This website helps you learn about the process of piecing together images of deep space in an attempt to create a composite, colored image like this one that I made earlier:
The final, composite image of Messier 17
If you are at all interested in checking this out for yourself, here are the links that you will need:
http://www.spacetelescope.org/projects/fits_liberator/datasets/
http://www.spacetelescope.org/projects/fits_liberator/stepbystep/
The first link will take you to a page with quite a few download links. Pick one of those, download the pictures that it presents to you, and then go to the second link that I provided and follow the step-by-step instructions. One little disclaimer – in order to do this, you will need to download Photoshop if you do not already have it. However there is no need to worry, if you go to Adobe’s website you can download Photoshop for free and use its free trial for up to 30 days. You could probably complete this project in under an hour, so I would highly recommend giving it a shot.
If you do not have the time or the desire to complete the project, that is perfectly understandable. Either way, here is a little summary of what astronomers must do in order to create a detailed, accurate, and colorful photo of the reaches of the cosmos. First, when NASA’s Hubble Space Telescope snaps a picture of a distant star millions of light years away, it is not taking the same type of picture that your average iPhone camera takes. Instead of using film or digital storage to collect the light that comes to it, it uses charge-coupled devices, most of which are sensitive to infrared light, not visible light. So, when the initial images are developed, they are simple, colorless photos, like these:
The blue layer
The green layer
The red layer
These photos are images of Messier 17, a nebula that sits about 5,000 light years away from Earth. To turn these boring images into one vibrant photo, like the one shown at the beginning of this blogpost, you have to layer the photos, the first layer with the lowest wavelength (so, the bluer one) and the last layer with the highest wavelength (the redder one). After doing this and messing with the coloring a bit through the hue/saturation, curves, and levels options, the result is a beautiful representation of a distant land that we know very little about. If you have not pieced it together just yet, the mundane, colorless photos above were combined to create the lively, colorful picture at the top of this blogpost. So, that’s a little “behind the scenes,” if you will, to how people create incredible images of outer space.
Messier 17, also known as the Omega Nebula, is a very interesting location in and of itself. It is a part of the Sagittarius constellation, and has a mass that equals about 800 solar masses. Its size is not just for show – it is known as one of the most luminous and star-producing regions in the entire Milky Way. It does not only stand out in this category; M17 is also one of the youngest known clusters with an age of just 1,000,000 years. Probably the coolest thing about this nebula is how many aliases it has. Some of these include the Swan Nebula, the Checkmark Nebula, the Lobster Nebula and the Horseshoe Nebula. The Nebula has so many names because of how varied it is. There is no single defining characteristic for the region, and instead many different parts of it resemble something we are familiar with (like a swan or a horseshoe).
