From GildasWiki

GILDAS documentation is still lagging. We are nevertheless making progresses (see e.g. the documentation of telcal, mira, class90, clic, mapping which are relatively recent). All the documents with mention Document probably older than you think in the title page indicates a much older documentation.

Program Documentation

GILDAS is composed of:

A kernel

SIC a command line interpreter with mathematical possibilities and direct access to internal and FITS data formats; SIC also includes a built-in GUI (Graphical User Interface) constructor; \doclocation{sic}

\greg{} an all-purpose 1-D, 2-D and almost 3-D graphical program. \greg{} has many facilities for astronomical data manipulation and analysis; \doclocation{greg}

\pygildas{} a Gildas-Python binding is currently under development. Please note that it has still a beta status; \doclocation{gildas-python}

Interactive programs

General purpose

\astro{} dedicated to ephemeris and observation preparation (e.g. \PdBI{} correlator setup); \doclocation{astro}

\telcal{} a library dedicated to the calibration of the telescope (pointing, focus, gain, ...); \doclocation{telcal}

Single-dish data processing

\mira{} dedicated to the calibration of the raw format (IMBFITS) and the writing in the \class{} data format of \thm{} spectra obtained in 2006 and after; for former data, users should use \otfcal{}; \doclocation{mira}

\class{} dedicated to the processing of single--dish spectra; \class{} is a successor of \oldclass{} which is not maintained anymore; \class{} is oriented towards the processing of a large quantity of spectra (see \newclassmemo{}); \doclocation{class}

\mopsic{} though not belonging to the GILDAS distribution, is the recommended package to reduce bolometric data from the \thm{} telescope (contact: \texttt{});

\nic{} is obsolete, i.e. it is not distributed anymore with GILDAS;

\otfcal{} dedicated to calibration of \thm{} On--The--Fly data obtained before 2006; for later data, users should use \mira{}; \doclocation{otfcal}

Interferometer data processing

CLIC dedicated to on-line and off-line calibration of PdBI; (pdf)

MAPPING dedicated to imaging and deconvolution of aperture synthesis data (pdf); MAPPING also includes an ALMA simulator;

Standalone tasks

Dedicated small programs to perform non interactive, time consuming processing such as transposition, fitting, reprojection, image processing, simulation, etc. Find the list here.


The Programming Manual gives all information required to develop new applications in GILDAS. It describes i) how to use the SIC command line monitor and the GREG graphical library, and ii) how to implement new GILDAS tasks.

Related documentation

ALMA simulator

The ALMA simulator has been created to evaluate the importance of the ALMA Compact Array (ACA) on the wide field imaging performances of ALMA. All information about the simulator may be found in the following ALMA memos:

  • # 488: Wide use of the simulator by our japonese colleagues to help designing ACA;
  • # 398: The most up-to-date description of the simulator and final results;
  • # 387: Preliminary results;
  • # 386: First state of the simulator.

PdBI additional information

Proposal preparation

useful when double sideband observations of narrow lines have to be planned.

Array operation

  • Amplitude Calibration describes the primary amplitude calibration: atmospheric calibration receiver and telescope dependent parameters. This document also applies for the 30-m calibration.
  • Interferometer Observer's Manual a complete observing manual for the interferometer.
  • Flux measurements details the observing techniques for flux density measurements.
  • Pointing User's Guide details the methods for pointing measurements and describes the POINT program.
  • Trouble Shooting Guide contains a (non-exhaustive) list of potential problems, with their causes and a description of diagnostic tools.

Data calibration

  • Calibration CookBook, a supplement to the CLIC manual, contains simple recipes to calibrate interferometer data.

NIC memos

For reference, even though NIC is now obsolete.

Description of the raw data format

Description is available here.

Calibration issues