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ALADIN(1) Virtual Observatory ALADIN(1)


aladin - interactive software sky atlas


aladin [options...] [filenames...]
aladin -hipsgen|-mocgen [-h] [options...]
aladin -help|-version


aladin is an interactive sky atlas for viewing astronomical images in the online Virtual Observatory (VO) developed by the Centre de Données astronomiques de Strasbourg (CDS). It is possible to superimpose entries from astronomical catalogues or databases with remotely accessed data fetched on demand.

Aladin can also open and save to a large number of astronomical image formats (FITS, HEALPix, JPEG/GIF/PNG/...); and table formats (FITS, VO-Table, CSV/TSV, S-extractor, IPAC-TBL, Skycat, ASCII, ...).

This manual describes only the command line parameters of aladin. The possibilities of the graphical user interface can be discovered with the Help menu once the program is started.


show top-level help
display the Aladin release number
skip internet connectivity tests (off-line usage)
start in full-screen, cinema, preview, or other visual modes.
script commands passed on the command-line
script-mode. Does not use graphical user interface. Equivalent to -noplugin -nohub
disable/enable starting the internal SAMP communcations hub for sharing data with other astronomical applications
disable/enable plugin support

Debugging Options

disable/enable features that currently in beta-test
disable/enable prototype feature. Useful for testing or when performing demonstrations
debugging trace mode
debugging extra verbose mode

HiPS command parameters

The -hipsgen command allows a script-/command-line based Hierarchical Progressive Surveys (HiPS) generation. The options can be given on the command line, or in a config file (param=configfile). Additional parameters may be retrieved with the command aladin -hipsgen -h.

Source image directory (FITS or JPEG|PNG +hhh or HiPS) or unique image or HEALPix map file (required parameter)
HiPS target directory (default $PWD+"HiPS")
Name of the survey (by default, input directory name)
HiPS identifier (syntax: [ivo://]AUTHORITY/internalID)
Name of the person or institute who builds the HiPS
HiPS status (default: public clonableOnce)
List of HDU numbers (0 is the primary HDU - default is 0)
Specifical BLANK value
FITS key to use for removing a sky background, or auto detection or percents of pixel histogram kept (central ex 99, or min max ex 0.3 99.7)
The source images are colored images (jpg or png) and the tiles will be produced in jpeg (resp. png)
Shape of the observations
Margins (in pixels) to ignore in the original observations (N W S E or constant)
Observed regions by files.fov or global polygon (in FITS convention).
Pilot test limited to the nnn first original images.
Debug information from -1 (nothing) to 4 (a lot)
incremental HiPS (keep weight associated to each HiPS pixel)
clear previous computations
Just print process information, but do not execute it.

MOC command parameters

The -mocgen command generates the MOC (Multi Object Coverage Map) corresponding to a collection of images or WCS headers. A MOC is a a coverage map based on HEALPix sky tesselation.

The supported formats are: FITS files, MEF files, jpeg or png files (WCS header in the comment segment), .hhh file (FITS header files without pixels) and .txt simple ASCII file (FITS header as keyword = value basic ASCII lines).

Verbose mode
Scan pixel values instead of using WCS image coverage
Alternate BLANK value (-strict only)
MOC resolution (default 10 => 3.345')
MOC output format (default FITS)
Previous MOC (if additions)
List of concerned FITS extensions
Recursive directory scanning
Output MOC updated continuously rather than generated at the end
Directory of images/headers collection
Output MOC file
Debug trace


Aladin is able to process the following file formats:

FITS (gzipped,RICE,MEF,...), HEALPix maps, JPEG,GIF,PNG
FITS, XML/VOTable, CSV, TSV, S-extractor, IPAC-TBL, Skycat or ASCII tables
Aladin or IDL or DS9 regions, MOCs
HiPS (Hierarchical Progressive Surveys)
Files with "*.aj" extension
Files with "*.ajs" extension


Aladin was written by Pierre Fernique (Aladin Desktop core base & documentations), Thomas Boch (many advanced Aladin Desktop features), Anaïs Oberto (RGB support, HiPS prototypes), François Bonnarel (Image calibration), and Chaitra (TAP,SIAv2 implementation).


Copyright © 1999-2017 Universite de Strasbourg / Centre de Donnees astronomiques de Strasbourg (CDS/CNRS)

Aladin is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3 of the License.

If the Aladin Sky Atlas was helpful for your research work, the following citation would be appreciated: This research has made use of "Aladin sky atlas" developed at CDS, Strasbourg Observatory, France. 2000A&AS..143...33B and 2014ASPC..485..277B.



The user manual is available in PDF format in french language at

An older version is available in english:

Dec 2017