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VOSpec Demo

Tutorial including video demo: http://www.euro-vo.org/pub/fc/recipes/VOSpec.html

Manual: http://esavo.esac.esa.int/VOSpecManual/

Start applet http://esavo.esa.int/vospec/ (needs some minutes of patience when starting the first time)

Goal 1: Combine spectra from several VO archives and visualize them together

  • Edit target name NGC3516 and click Go. A Server Selector window opens.
  • Select the VO archives you are interested in or Select All and click Go. A list of available spectra for the requested target will appear in the lower part of the main window.
  • Select the following spectra:
    • From INES choose first and last NGC3516
    • From Far Ultraviolet Spectroscopic Explorer choose 2nd and 3rd NGC3516
    • From Hubble Space Telescope Faint Object Spectrograph first and last one.
    • Click Display. All spectra are displayed together in the main window as soon as the data arrives from the different servers.
  • Doubleclick on a spectrum name in the list below the display area to open an information panel containing the metadata.

Graphic Mode Panel (bottom left in the main window)

  • Click on a coloured square to display one spectrum only.
  • Mark several checkboxes and click View to display a selection of spectra.
  • Select a different graphic mode in the drop down boxes.

Units (Upper left corner of main window) (optional)

  • Select wave and flux unit and mark checkbox to change from logarithmic to linear scaling. Click View.

Redshift and De-reddening:(optional)

  • Edit redshift and mark the checkbox then click View.
  • Mark the checkbox for dereddening and click View. In the new window you select the appropriate reddening law, edit additional parameters and mark the checkbox. Click View again to make the changes visible.

Goal 2: Save spectra to file

  • Select from menu: File - Save As - VOTable ... (extension?)

Goal 3: Load local file

  • Select from menu: File - Open .. (Extension?).
  • In the unit window you can correct the units if necessary. Either choose from the predefined ones or edit your own (including parameters for the dimensional equations!).

Goal 4: Test some analysis features

  • You might want to open a full size plot window before you start analyzing the plots by clicking the icon "Plot Full Size". If you close this window, control is returned to the main window automatically, however you need to refresh the plot by clicking Display again.

Fitting (here: Gaussian line fit)

  • Select a suitable wavelength/energy range in the main display panel by click-dragging the mouse over it.
  • Click on the "Fitting Utilities" icon. A window will open.
  • Go to the Gaussian tab and click Generate to start the caluculation. The parameters of the Gaussian fitting function are displayed in the fitting window, and a plot of the fitting function is superposed to the selected spectrum in the main window.

Line Identification

  • Click on the icon "SLAP"
  • Celect a region around your line of interest by dragging the mouse while pushing its left button. A catalogue selector window will open.
  • Check the line catalogue(s) you want to use, then click Select. In the lower part of the selector window the list of all lines within the marked wavelength range will be displayed.
  • Move the mouse across the plot to display lines with their names.
  • Click on the icon again to exit the SLAP mode.