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FITSH - a software package for astronomical image processing

Welcome to the web page of the FITSH package, an open-source software collection related to astronomical image and data processing. This page gathers information about the program (including documentation and examples), this is the primary download source of the package itself, and additionally, serves a public forum for the program users in various topics.


This software package provides a set of independent binary programs (tasks) that are designed for execution from a UNIX command line shell or shell script. Each of these tasks performs a specific operation (e.g. transforming an image to another reference frame, search and identifiy stars or other point-like sources, do photometry, transform/display a FITS image to a popular graphics format, ...) while the details of a certain operation are specified via command switches and arguments. Therefore this package does not need any higher level operating environment than a standard UNIX shell, however, processing the related data might require a little more knowledge of the used shell itself (the related documentation and examples found in this page use the bash shell). Additionally, some of the processing steps might require minor or basic operations performed with other tools like awk or text processing utilities (sort, uniq, paste, ...). For a brief summary about the individual tasks, check the ``Tasks'' section of this web page.

And something little more about the data structures. The tasks and utilities found in this package processes astronomical images that should be available in FITS format. Any other data (object lists, descriptive files, ...) are manipulated as simple ASCII text files, so independent software environments and data processing languages (such as IRAF or IDL) can easily process the outcome of these utilities. In other words, non-imaging data are not stored in specific FITS extensions (textual or binary tables), instead, simple text files are supported both as an input and output.


  • Basic information about the images or other FITS data, pixel statisitics.
  • Conversion of FITS images to more easily presentable formats.
  • Querying and modification of FITS header keywords.
  • Calibration of raw images, including the masking of bad, saturated or otherwise unuseable pixels.
  • Arithmetic operations on images, both on per-image and per-pixel basis.
  • Combination of multiple images into a single one.
  • Generic spatial geometric transformations of images (shifting, dilating, shrinking, clipping, higher order polynomial transformations, ...), including the registration of images to the same reference frame.
  • Generation of artifical images.
  • Detection and characterization of stellar profiles.
  • Coordinate list manipulation (fit and evaluation of geometric transformations, point matching, pair matching, matching by identifiers, ...)
  • Photometry (aperture, image subtraction, analytic profile modelling, PSF and various other sophisticated combinations of these).
  • Regression analysis and general numeric data manipulation.
  • Very simple way of parallel processing, using the pexec utility (that is available also as a GNU/Linux package as well, on recent distributions).

Download and installation

The current stable version of the program is 0.9.1. You can browse the available versions here. After downloading and extracting the source archive, the compilation and installation of the package from this source tarball follows the well-known

./configure && make && make install

procedure. Alternatively, on dpkg-based GNU/Linux systems (e.g. Debian, Ubuntu), you can create a DEB package and install FITSH using your favourite package management tool. You may find more details about the installation steps here. See also the full changelog of the package (since the version 0.9.0).

Getting started

Here we refer to our ``getting started'' section. This section also contains a brief description of other optional software packagesthat can be useful while using the FITSH package.


Currently, documentation about this program/project is available in the following forms:

  • All of the programs/tasks are capable to provide a shorter and a longer list of command line help options and description that are available via the --help and --long-help options, respectively. The --help option simply lists the available options and switches with a minimalistic references of the actual syntax while --long-help gives a more detailed description (that is also adequate to be converted into a nice UNIX manual page using the help2man utility).
  • You can find a more detailed summary about the specific programs/tasks here.
  • There is an all-in-one document in PDF format describing the above mentioned options and features some examples as well.
  • See also the ``Examples'' section of this web page.

Keep in mind that the documentation is not really complete. There might be features that are mentioned somewhere and does not have a related listed command line option or vice versa. Please provide any information about these issues, such reports are highly welcomed!

Forums and newsletters:

This web page also serves a public forum for the program users. Anyone can access the forum topics and the related comments without any limitations, however, starting a new forum topic and/or providing additional comments requires registration (with a valid email address) and a successful login.

Registered users can also subscribe to a newsletter, that is sent when a new release of the FITSH package becomes available. Users who are already registered can change the subscription status on the personal data page.


  • Information about the FITS format.
  • The paper describing the package.
  • The PhD thesis in which some algorithmical details of the various utilities are discussed.
  • The paper describing the details and features of the catalogue cross matching and astrometry as implemented in the grmatch task.

Although FITSH is a relatively new public package, it is not without a history. As of now, there are mor than 50 papers or preprints (from the last 5-6 years) in which one or more of the FITSH tasks have successfully been employed at some level. These papers received more than 1200 citations, so this package might also be worth a try. See also this list for some interesting references.


User contributions are also welcomed! If you find a bug, you can either submit a report or provide a patch if the solution for the bug is known. Don't forget to provide some information about the host operating system and attach the essential files which cause one of the program to fail. Please be as terse as possible. The most effective way is to send a single tar or tar.gz file that contains the essential data files and a simple minimalistic shell script that produces the unexpected behaviour if started.

Copyright, contact, ...

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a practical purpose (an excerpt from the GPL). The content of this web page is copyrighted by András Pál, unless explicitly noted.

If you find this program useful in your research, please cite this paper, as something like ``Pál, A. 2012, MNRAS, 421, 1825''.

Some examples:

Optical lightcurve of (20000) Varuna
A composite image of M74
Analysis of transiting extrasolar planets
Implementation of the IMEXAM features