Aladin - Frequently Asked Questions
P.Fernique - April 11th, 2005 - edition 7.0

Authors:

• Pierre Fernique[CDS]: base code
• Thomas Boch [CDS/AVO]: Contours, Filters, DataTree, Crossmatch, ``Show me'' tutorials, column calculator (dev. for AVO project)
• André Schaaff [CDS]: VizieR access, VOTable/XML parsing
• François Bonnarel [CDS]: Image calibration
• François Ochsenbein [CDS]: Coordinate manipulation
• Anais Oberto [CDS]: RGB feature (developed for IDHA project)
• Olivier Bienaymé & Mark Allen & Daniel Egret [CDS]: Documentation

Contributions:

• S.Kale [VO-India]: VOplot plug-in facility
• R.Savalle [CFH]: CFHT FoV
• T.McGlynn [HEASARC]: Colormap adjustement original java code
• T.West: BMP writter original java code
• R.White & P.Dowler: Hdecomp original C code and java code

Copyright:

• ULP/CNRS
• Portions of the code (contours, filters, dataTree, crossmatch, column calculator) have been developed in the framework of the Astrophysical Virtual Observatory (AVO), an EC RTD project 2002-2004
• The RGB feature has been developed in the framework of the IDHA project (ACI GRID of the French Ministere de la Recherche).

Aladin has been choosen as the base core of the Astronomical Virtual Observatory prototype in 2002 and 2003 : "the AVO prototype"

Aladin is also used by other astronomical institutes such as NED (2000), CFH (2001), XMM (2001), CADC (2002) , LEDAS (UK) (2004), IBVS (2005), and ESO (2005) as a visualisation tool for some of their own data.

The release 2.0 in November 2003 integrated the following points:

• Meta data representation: shows image data server results either in list representation or in tree representation, and provides more meta information on images (FoV, available codings...)
• IDHA and SIA compability: allows you to integrate in Aladin IDHA or SIA image servers.
• ExtApp interface: Aladin can interact with external java applications such as VOplot (VO-India) by a simple java interface (see below)
• Autocut ehancement: allows you to reload the original image pixels in order to re-cut the image dynamic.
• Filter popup menu: helps you to write a filter by providing current column names, UCDs syntax...
• Autoscan user directory: creates a meta data representation from a user directory.
• Manual catalog reduction: allows you to calibrate a catalog without coordinates.

The release 1.4 in January 2003 integrated the following points:

• Object filters: allows you to control object overlays (shape, color, size) according to object measurements.
• Manual astrometrical reduction: allows you to recalibrate images.
• Plane stack: illimited number of planes - hierarchical representation by folders.
• Popup menus: frame view popup menu and stack popup menu for a more flexible feature access.
• Megacam FoV: Field of view of the MEGACAM instrument on CFH telescope.

The release 1.3 in June 2002 integrated the following points:

• RGB images: allows you to create an RGB image. An RGB image is a composed colour image built from three images.
• Contours: allows you to draw isocontours ou of a selected image.
• Links to original images: provides a HTML page with links to the original images loaded in Aladin applet or standalone.
• Splittable interface: Allows you to set the object informations in an independent window .
• Flip/flop feature: Allows you to inverse pixel images (top/bottom or left/right) and their associated astrometrical reduction
• Arrow key control: allows you to focus the color mapping and the wen position not only with the mouse but also with the arrow keys.
• LEDA access: Aladin offers access to LEDA (Lyon-Meudon Extragalactic Database).
• FIRST and NVSS access: Aladin offers access to radio images from NRAO.

The release 1.2 in December 2001 integrated the following points:

• 2MASS access: Aladin image server can provide 2MASS images.
• SkyView, SUPERCosmos, DSS mirrors sites: Aladin offers new access to data servers.
• Script mode: Aladin can be controlled by command lines. This method can be a way both to work with Aladin STANDALONE in a batch mode or to pre-configure Aladin APPLET (see script section).
• The manual: in addition to this FAQ, a Aladin manual is available.
• blinking sources: The current source (under the mouse) is blinking to help you see it more easily.
• Low resolution: Aladin image server can provide DSS images in low resolution. So, three resolution are available: the PLATE view (about 5x5 degrees), the LOW resolution (about 1.5x1.5 degrees) and the FULL resolution (about 10x10 arcmin).
• Field of View feature: It is possible to overlay the field of view of some major instruments (presently: CFH12K camera, XMM instruments and WFPC2-HST camera). Rotation of the field can be monitored from the 'Prop.' window.
• Scale plane: on the top of the plane stack, you find a new kind of plane: the scale plane. This plane contains three additional things that you can display on the current view:
  1. the scale: a small line gives the scale of the view;
  2. the coordinate grid (for constant RA and DEC values);
  3. the target: a large cross (+) indicates the object or position used as center in the initial query.
• shortcut commands: when you click in the rectangle indicating the current position (just below the menu), you can submit a "shortcut command" allowing you to query directly data servers. See the corresponding section.
• Coordinate manipulations: to visualize the location of a specific object or position in the current view, you can simply click in the rectangle indicating the position and type the coordinates (or Simbad identifier). After pressing the 'RETURN' key, the current target (large +) will move at the corresponding position in the view. Also if you click on the view, the corresponding position will be automatically memorized in the position rectangle. Move the cursor in the position rectangle to retrieve this position and possibly cut-and-paste into another application.
• Aladin wink: click on the eye at the top of the plane stack to switch on/off the overlay planes.
• Click-and-drag in the measurement window: you can scroll up/down/left/right the contents of the measurement window (at the bottom of the Aladin Interface) just by clicking-and-dragging on it. It allows you to consult more easily long lines and long lists.
• Additional servers: with the Standalone version, users can define their own servers (for images or data). See the corresponding section.

But Aladin offers you an access to most of the astronomical servers over the world.

In the first case, you can run it directly from a browser such as Mozilla or IExplorer. This is the simplest solution. By default, an applet has several security restrictions. However, if the user accept the code certification when Aladin applet is starting, Aladin will run in full mode, otherwise it will run in a restricted mode (no local disk access, no printer access).

The alternative is to download the Java code to run Aladin as a standalone application. In this case, you need not to launch a browser to use Aladin and there is no security restriction.

Aladin developement has particularely taken care of the java performances. So a small Pentium is good or any other recent workstation, Mac, etc.

(*) we don't support Java 1.02 since January 2001 (Aladin release 1.1) and Java 1.1.2 since June 2002 (Aladin release 1.3). However if your work requires this constraint, it is possible to obtain the previous Aladin release by sending an email at question@simbad.u-strasbg.fr.

Aladin APPLET is compatible with basic JVMs (Java 1.1.4. - without SWING package).

However, in some cases, positions could be off up to 4" and can't be used as astrometric positions. The main reasons are:

1. The pixel is 1"7 wide for the STScI images and 0"67 wide for the MAMA images.
2. The error on the position given by the DSS-I calibrations (STScI images) could be of the order of 4" on the plate edges.

If you use the Applet version throught Netscape 4, you can expect to be able to load images with 1024x1024 pixels but not really more. It is due to a memory allocation limitation of the Netscape 4 JVM. You haven't the same limitation with recent browsers.

Too large images are automatically cropped in case of memory limitations.

For the standalone version, if you use the Aladin launcher provided with InstallAnywhere installation, the default memory allocation is 64Mb. If you want to increase this value you can easely patch the InstallAnywhere configuration file. Edit the file Aladin.lax in the installation directory and modify these two following lines according to your needs :

If you use Aladin without the InstallAnywhere launcher, you can also specify manually the memory size required by your JVM. To do that you can play with two parameters of the java command:

• -ms<number>: set the initial Java heap size
• -mx<number>: set the maximum Java heap size

Tip: If you select "8 bits" in the pixel selector, Aladin does not load in memory the full pixels of the visible views. It is a good method to reduce the memory usage.

This control mode can be used interactively via a window console (Menu Tools -> Aladin script console) prompting each command, or via the standard input (standalone version only). So you can used it by redirecting a script file or the standard output of another program (see the PERL example below). In this case, you can use the ``-script'' parameter on the command line hiding the graphic interface.

It is also possible to use it in Applet version in order to launch Aladin in a pre-configured state. See the question Can I launch Aladin Applet with predefined images or data for this purpose.

Tip: You can also pass any script command into the rectangle indicating the current position.

Here is the script command list:

http://aladin.u-strasbg.fr/AladinJava?script=get+Aladin(DSS2),Simbad,NED,VizieR(usno2)+NGC1097;grid+on;sync;reverse

The interface between Aladin and VizieR presents three alternatives for the choice of tables/catalogues. Once you have pushed the ``load'' button, you can select:

• VizieR catalogs: this is the full VizieR access mode:
  1. by just pushing the SUBMIT button, all catalogues having sources in the neighbourhood are retrieved and presented; catalogues in this list can then be selected by a mouse click on their title.
  2. by entering words in the Author, free text... box (e.g. white), the list of catalogues is restricted to those having the specified word(s) in their title and having sources in the target neighbourhood.
  3. by clicking on a selection of keywords, the list of catalogues is restricted to those having all keywords (i.e. keywords are and'ed) and having sources in the target neighbourhood.

• Surveys in VizieR: the largest all-sky surveys available are listed, and any of those can be selected by a mouse click on its title.

• Missions in VizieR: the mission logs available are listed, and any of those can be selected by a mouse click on its title. If images are attached to these logs, buttons will appear in the data line to allows you to download directly preview images in Aladin.

Note: The PNG format is supported only if you have a recent JVM (>=1.4)

Remember that the "get MyData" command syntax is the following:

get MyData(YourUrl[,plane_name][,origin])

plane_name is the name used in the Aladin stack and origin is displayed with the properties associated to this plane. Do not omit to httpencode the command even YourUrl parameter. If the URL contains a comma, you can encode it by the HTTP syntax %2C

Note: The older syntax "get Local(...)" is still supported

Since version 3.0, Aladin is looking for the AlaGlu.dic first in the Aladin installation directory and second from the jar file. Notice that you really have to extract the AlaGlu.dic file and save it into the Aladin installation directory. If you simply update the AlaGlu.dic file directly into the jar file, your modifications will be rejected by the jar loader (signed jar file).

To extract AlaGlu.dic file, you can use Winzip tool or any equivalent tools. You can also use the jar command tool:

• jar xvf Aladin.jar AlaGlu.dic

The servers have to be accessible by a simple URL with a HTTP GET method. The syntax required for these server definitions follows the GLU recommandations. Adapt this short example to your own needs :

• ActionName: Unique identifier
• Description: Server description
• Aladin.Label: Button or menu label
• Aladin.Menu: label of upper-level button (in case of a submenu)
• Aladin.LabelPlane: Template of the plane label. $n will be replaced by the corresponding parameters.
• DistribDomain ALADIN: keep this line ``as is''.
• Owner CDS'aladin: keep this line ``as is''.
• Url: Server url template with $n variables specifying the fields which have to be filled up by the users.
• Param.Description $n=: Description of the field number n
• Param.DataType: Data type of the corresponding parameter. The available formats are: Target(COO[b|d] | RA[b|d] | DE[b|d] | SIMBAD | NED) and Field(RA | DE | SQR | RADIUS) - For COO, RA and DE, b extension is for blank separator instead of ``:'' and d extension for degres instead of sexagesimal representation. It assumes that coordinates are in J2000 frame.
• Param.Value: Default value or list of available values for the corresponding parameter
• ResultDataType Mime(xxx): To specify the data type provided by the server. For images: image/fits - fits file, image/gfits - gzipped fits file, image/hfits - hcompressed fits file, and for data: text/plain, text/tsv or text/csv for data in tab separated value syntax and text/xml for data in XML/astrores syntax (see the corresponding sections).

The servers that you have defined will be accessible by the buttons at the right side of the server selector window.

Firstly, you query the VizieR service for the mission log of the archive (for example, the HST log or the FIRST log) around a target.
Secondly, you select the resulting positions in the view and look at the corresponding data in the measurement window. If you find a button ``Image'' in the data line, click on it to retrieve the corresponding archive image. A new plane will be created automatically in the stack.

** How can I cut-and-paste informations (measurements, positions,...)

Is there a manner to convert object coordinates ?

Additionally, if you click on the data line, the current position is memorized into the position rectangle and you will be able to cut-and-paste it.

Just type the following script command in the ``location rectangle'': ``trace x'' where x can be 1, 2, 3 or off

However, the time required to detect that there is no network varies between a few seconds until more than 1 minute (depending of your JVM). Therefore, you can start Aladin with ``-local'' parameter to force it without network.

Example: lax.nl.java.option.additional=-Djava.security.policy=java.policy

• Remove several views and/or planes at a time: specify several views by clicking on them or several planes by clicking on their name, with the SHIFT key down. After that, press the Del button (without the SHIFT key pressed).
• Remove all views and/or planes: With the SHIFT key down, press the Del button to remove all views. In there is no views, all planes will be removed.
• Select several sources not in the same rectangular area: maintain the SHIFT key down during the selection.
• Open anchors in NEW browser windows: click on the anchors with the SHIFT key down.
• See all the image: click in the Zoom Frame (at the bottom-right of the screen) with the SHIFT key down to automatically adjust the zoom factor in order to see all the image in its view.

• Click on a plane icon to activate (or unactivate) the plane.
• Click on a plane name to select it; then the tool buttons which are authorized for this kind of plane are activated. Maintain the Shift key to select several planes together
• Click and drag the plane icons in the stack to change the order of the display. The first image hides all planes underneath.
• Click and drag the plane icon from the stack to a view panel (especially in multiview mode) to create a new view for this plane (see next section).

A blue border show you the selected view(s) for which an action can be operated (Del, Hist, Zoom, RGB, rsamp). Clic on a view to select it. Maintain the SHIFT key to select several views. You can also press CTRL+A to selected all visible views.

Aladin always tries to center the zoomed views on the last position of the "reticle" (the large magenta cross).

• Automatically:
  Aladin provides a self-extracted contour feature. Select the ``Cont'' tool and follow the instructions.

• Manually:
  To make a contour, use the ``Draw'' button. You have two modes:
  - click-and-drag mode: draw a ``hand-line''
  - click-and-click mode: draw a ``poly-line''. You have to exit the cursor of the view to stop the polyline.

  You can move a manual contour with the ``Select'' tool by clicking-and-dragging one of its control points. It means that you have to select the contour and after that click-and-drag one of these control points (little squares on the contour).

See the documentation available in the filter frame.

You can also pass through the "Tools -> Image astrometrical calibration" menu.

To force an Aladin redisplay, click twice in the stack eye.

In fact, when it is starting, Aladin queries several remote servers to adjust its configuration. It calls the nearest GLU(*) site to add the last available servers and it calls the nearest VizieR site to retrieve the VizieR keyword lists. Before that, Aladin cannot build the server frame.

(*) The GLU is a distributed resource directory allowing Aladin to access transparently data servers. It is a CDS developement.

If you did not see the certification window when Aladin started, you should install a more recent browser. Otherwise, restart your browser and accept the certification.

Thanks to Eric Lafortune for its free obfuscator tool: "Proguard" which reduces Aladin size with a factor of 25%.

Some help if java is disable:

• Explorer: search in "Start (on desktop) -> Control Panel -> Internet options -> Advanced -> Java"
• Netscape 4: search in "Edit -> Preferences -> Advanced -> Enable java"
• Konqueror: search in "Configuration -> Configure Konqueror -> Konqueror browser -> Java -> Always activate java + verify java search path"
• Netscape 6/7, Mozilla on Unix OS: you have to create a symbolic link between the Mozilla/Netscape plugins directory and the java installation plugins so library. For example, for a Blackdown jre 1.4 distribution and Mozilla 1.5, you have to adapt these commands:
  cd /usr/local/mozilla/plugins
  ln -s /usr/local/j2re1.4.1/plugin/i386/mozilla/javaplugin_oji.so
  WARNING: the java machine and the browser have to be compiled with the same GCC version. For example: Mozilla 1.0 -> gcc 2.xx, Mozilla 1.5 -> gcc 3.xx. It means that for Mozilla 1.5 you have to choose a blackdown java distribution for which gcc 3.xx has been used (www.blackdown.com). It is not the case for Sun JDK distribution.

Aladin uses only three fonts: Courier, Helvetica and Times. All implementations should provide them. If this is not the case of your configuration, try to adapt the file font.properties according to your fonts.

You have to install a new JVM machine, and start again the Aladin installation, or your can copy individually Aladin.jar file and run manually by "java -jar Aladin.jar" command.