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What It Is
For those of you who don't know what FITS Liberator is, it's a freeware plugin you can download from NASA/ESO that allows you to open FITS format files directly in Photoshop. This allows editing access to all kinds of astro data, including for example the Hubble datasets, data saved from Maxim DL, etc. NASA/ESO just released a new version, and you can get it here: http://www.spacetele...fits_liberator/
There are quite a few functions and features on the FITS Liberator v2 dialog, and this can seem incredibly daunting, but just remember this: The plugin really just facilitates opening one channel file into Photoshop (e.g., Red data, or Luminance data, etc.), and provides you some data stretching (lightening) functions along the way. Keep in mind the data in FITS files is most often in Linear space and has to be stretched to form an image we can see or print.
Overview and How-To
Here's a layman's overview of the way I use FITS Liberator v2 to construct an RGB file in Photoshop CS2:
1. Open each channel file (or plane of data), Red first, then Green, then Blue as a 32 bit floating point grayscale image. You set the parameters in the FITS Liberator dialog during the file open process.
2. Paste each grayscale image as the appropriate color channel in an 32 bit RGB image.
3. Stretch the data a bit further while still in floating point mode (Photoshop CS2 only).
4. Down convert to 16 bits per channel.
5. Flip the image vertically (for some reason the images seem to open upside-down).
6. Run the Levels function to bring all the color channels into roughly the same luminance levels.
7. Do further editing.
In step 1, you must supply parameters to the FITS Liberator dialog. There are many, many combinations that you can choose, but I have found a set that seems to give good results for virtually every image. I figured that stretching the data quite a lot in the plugin, which is at the highest possible bit depth (e.g., 32 bit floating point) makes the most sense, so I chose a function that does that. There is a checkbox that allows you to have the plugin remember the settings (making them sticky), so when you use it next time the defaults will be mostly right. After that you can pretty much forget about the parameters. Here are the settings I use:
Freebie!
Does this all seem like WAYYYY too much work? Now the good news...
I have built steps 1 through 6 into a handy action that I am going to include in Astronomy Tools v1_4, and which I am providing here separately. With this action, you need only select the file(s) to open for step 1 when prompted to open Red, Green, and Blue data in that order, then fine tune the Exposure dialog sliders when prompted in step 3 to stretch levels, then push around the Levels dialog sliders for each of the color channels in step 6 to get the colors just right.
Please click here to download a zip file containing my FITS Liberator Action
Look in the ReadMe.txt file I've included in the zip file for instructions on how to install the action.
If I should update the action or add more functionality I'll update the zip file at the link above and post a new message in this thread.
Freebie!
If you don't already have some, and are interested in downloading some FITS files to test the action and practice editing, you can find some at the NASA/ESO link I provided near the top of this post. There are some other good ones by Jim Misti online here:
http://www.mistisoft.../index_fits.htm
Please let me know if you have any trouble with the action, and whether you find this helpful.
-Noel
