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Aladin demonstration

This tutorial was developed for Aladin V4 (2007). Aladin homepage: http://aladin.u-strasbg.fr/aladin.gml. See also: http://aladin.u-strasbg.fr/tutorials/

Loading images and tables - Step-by-step

  • Start from http://aladin.u-strasbg.fr/java/nph-aladin.pl?frame=get&id=aladin.jnlp. If Java is installed correctly, the Java standalone version will load. Firewall may be an issue. Otherwise, download the full Aladin version
  • First retrieve data: Click [Load].
  • Take a look at the load menu: Image sources are on the left, catalogs on the right, Others on top.
  • Images:
    • Choose source "All VO" and target e.g. M104. Radius 0 arcmin (Backup 12:40:05,4 -11:37:27,4 )
    • Wait for the results to come in. Select a few images. Make sure SERC and POSSI in included, as well as one 2MASS and IRAF each as example. Then click [Submit]
    • Watch how the data is loaded in Aladin layers at right.
    • Browse through the layers. If necessary, delete some non-interesting or failed ones (right click).
    • Check properties of an example layer, look at the fits header (richt click)
    • Select three layers of choice and create a RGB image: Nice!
    • Try a few of the tools: Zoom in and do a plot using the "dist" tool.
    • Try out colouring an image, display all images with multiview and create a movie (assoc)
    • If suitable, resample, contour and change pixel mapping
  • Let us now try the catalog data retrieval:
    • Click load again, select VO catalogs - VizieR. Select some sample data, e.g. II/246 IR 2MAAS All-Sky Cutri+ 2003
    • Show tabular data overlay. When mouse hovers over a data field, the UCD is shown.
    • Click on details. Open Web page, load additional image, load article
    • Show VoPlot of data.

IDL

See http://eurovotech.org/twiki/bin/view/VOTech/AladinIDL. This Tutorial is based on the updated IDL procedures for Aladin, to be published soon. See IDL site by Iliya Nickelt

  • Configure the IDL Java Bridge correctly so that the aladin jar is in the JVM_PATH. Instead of starting Aladin,
  • start IDL and do a IDL> a=launch_aladin()
  • continue with the demo as given above, retrieve some image data (in this example: Possi) and some tabular data (in this example: II.246@]
  • Retrieve the image data: IDL> get_image, a, 'POSSI*', im, hdr, /verb (ignore a potential readfits error)
  • IDL> tvscl, im>100
  • IDL> plotcut, im>100 ; iLIB routine
  • (do other "scientific" examples here, eg. fit a Gaussian through a y-cut of the disk to measure the angle etc.)
  • Retrieve a table: get_table, col=['RAJ2000', 'DEJ2000', 'Jmag'], ra, dec, mag, plane='II.246*'
  • IDL> ra=reform(double(ra)) & dec=reform(double(dec)) & mags=scale(reform(double(mag)))*255 ; mags scaled to 8bit color values
  • IDL> plot, ra, dec, psym=3 ; pretty booring
  • IDL> loadct, 5 & for i=0, n_elements(ra) DO oplot, [ra[i]], [dec[i]], col=mags[i], psym=4; aha!
  • finish with IDL> stop_aladin, a (or just close the applet...)