FITS Liberator

The ESA/ESO/NASA Photoshop FITS Liberator is a free plugin for Adobe Photoshop, which makes it possible to process and edit astronomical science data in the FITS format to produce stunning images of the universe.

The FITS file format archives nearly all images of stars, nebulae and galaxies produced by outer space and ground-based telescopes from all over the world.

The engine behind the FITS Liberator is NASA’s CFITSIO library. FITS is an abbreviation for Flexible Image Transport System and has been a standard since 1982 and is recognized by the International Astronomical Union.

Although the first version of the software was an excellent tool mainly for professional astronomers, efforts have been made to bring high quality astronomical images to the homes of amateur astronomers, educators and students. The FITS Liberator has also become the industry standard for professional imaging scientists at the European Space Agency, the European Southern Observatory and NASA. It is utilized on images from the Hubble Space Telescope and the Very Large Telescope (VLT), among others, to craft beautiful astronomical colour images.

The first and second versions of the FITS Liberator were released in July 2004 and in August 2005 respectively. The latest version of this image processing software, V.2.1, was released in November 2006 and is available for download at the European Homepage of the NASA/ESA Hubble Space Telescope.

Version 1

Version 1 of the ESA/ESO/NASA Photoshop FITS Liberator was completed in July 2004 by imaging scientists at the European Space Agency, the European Southern Observatory and NASA. Version allowed all types of FITS images to be opened and also some limited interaction with the images.

Version 2

1. The preview window2. Histogram3. Tools4. Statistics5. Advanced tools for scaling and stretch

The simple workflow is to open a FITS image, study it in the Preview window, adjust the black- and white levels (6) to give a reasonable contrast, and then set the input range for the scaling of the image by clicking Auto Scaling Button (7). Now different values of the Scaled Peak level can be tested to scale the image more or less to better fit with one of the possible Stretch functions (8).]

Version 2 of the ESA/ESO/NASA Photoshop FITS Liberator image processing software made it both easier and faster to create colour images from raw observations. Its numerous improvements included, among others:
* FITS images with up to 4 billion greyscales can be processed (32 bit support).
* FITS images with up to 500 million pixels or more can be processed (100 times larger than standard images from a digital camera). "The numbers indicate:"
* With a re-designed workflow and improved user interface, it is easier to use. The plug-in, for instance, remembers previous settings.
* New options for advanced scaling and stretching.

A whole section of v.2 was dedicated to inputting metadata, and the user also had access to a text version of the original FITS header.

With the advent of the FITS Liberator v.2, it became possible for people at home to create spectacular pictures like the iconic Hubble image “Pillars of Creation” in a matter of minutes.

Now, an updated version of the popular software containing new scaling and stretching tools to better manipulate astronomical images is available. One of the key updates in v.2.1 is the ability for users to embed descriptive information about the image and what it shows, so-called metadata, directly within the final image. Based on a new standard for Astronomy Visualization Metadata, this information is stored in the standard manner like that used by digital cameras to record exposure information.

Version 2.1 of the ESA/ESO/NASA Photoshop FITS Liberator has been improved in several areas, some of which are:
* Update of Metadata Support to Astronomy Visualization Metadata version 1.0 standard.
* Advanced stretching and scaling functions.
* Support for Adobe Bridge added.
* Significant speed improvements on Mac OS X.
* Minor bug fixes.
* New Extras.

The ESA/ESO/NASA WFPC2 Mosaicator: This new add-on tool works on Hubble WFPC2 images. It will generate a single WFPC2 mosaic'ed file from one WFPC2 file containing four CCD images in individual planes.The ESA/ESO/NASA FITS Concatenator: This Adobe Photoshop script will combine the metadata from two or more individual exposures after the FITS Liberation process.

How to use it

The ESA/ESO/NASA Photoshop Liberator is fairly self-explanatory. A User's Guide, which focuses on explaining the various features, sliders and buttons in the Graphical User Interface (GUI) for the plug-in, can be retrieved from the European Homepage of the NASA/ESA Hubble Space Telescope.

External links

*http://www.spacetelescope.org/projects/fits_liberator/index.html
* [http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html NASA’s CFITSIO]