The Half-Astrophysicist Blog

Make Your Own Pretty Pictures

Pretty pictures are a good way for astronomers to make the news.  A lot of work goes into those images as they data is usually pretty ugly when it comes out of the scope.  Once it is all cleaned up and made presentable, astronomers then have to make a nice pretty color picture out of it all.

While you might not be able to get time on one of the big telescopes, there are ways for you to do that last step and combine images to make your own pretty picture.  Today’s Chandra Blog talks about the Open FITS Project.  Open FITS is working to give people the tools and knowledge to try their hand at some basic image processing.  FITS is the file format (Flexible Image Transport System) that astronomical images use.  You need special software to work with FITS files (or plug ins to allow your program to import FITS files).

Fortunately, there are some good free options out there.  The Open FITS Project uses GIMP for a lot of their work (ImageJ is another option).  GIMP is kind of the poor man’s Photoshop (in the respect that it’s free…doesn’t quite do everything Photoshop does, but for a free program, it is very powerful).  Once you install GIMP, you can use it to open FITS files and away you go.

Telescopes take all images in black and white.  To make a pretty color image, you have to combine images through three different filters: One filter is assigned to the red channel, one to the green and one to the blue.  If you use data from outside the visible spectrum, you still use three images for each of red, green and blue.  Usually, the shortest wavelength (highest energy) image is assigned to blue and the longest wavelength (lowest energy) is assigned to red.

And that’s what Open Fits does.  Right now there are six different objects you can try your hand at.  Open the three different images and combine them in GIMP.  You can change the intensity of the colors and rescale them to bring out different features.  Astronomers try to make decisions that are both visually pleasing and highlight the science at the same time.

If you have Photoshop, you can try your hand at Hubble data using FITS Liberator.  I don’t have Photoshop, but I am getting more into photography and might just have to use my academic discount to get myself a copy.

So give it a shot and play astronomer for a day.


July 20, 2010 - Posted by | Astrophotography

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