• Search for images of the bright galaxy M51 in Aladin.
• Try the various image servers: The Aladin image server, Skyview and Sloan Digitial Sky Survey
• Try the 'all VO' access (selecting image servers) - Note the method for selecting images at a given sky location. Clicking in the image puts a tick in the selection boxes of the available data.
• Make a colour composite image using the RGB tool.
• Use the multi-view windows to manage the various images you have in the 'stack'
• Try the 'match' button at the bottom of the image window to align the image for synchronized zooming
• Try the transparency control for viewing images overlaid on each other
• Overlay as SIMBAD identifications using the SIMBAD link in the Server selector window

- Try 'with no filter' for a simple listsing of the IDs
- Try with 'Simbad filter' (colorized) to see how the same info can be presented in detail
(optional - open the 'properties' window for the Simbad plane to see or edit the filter)

• Filtering of sources can also be done interactively with Topcat. Start Topcat, and send the SIMBAD plane to Topcat (right-click on the plane in the stack, and 'Broadcast selected tables to..'
• View the table values in Topcat. Make a plot of the positions and try the area selection tools to select a number of points in the plot. Note how the selected subset may be transmitted back to Aladin to highlight sources from the original Simbad plane.
• Make a subset of the brightest HII regions, and send the table back to Aladin using the Topcat 'Interop' menu
• Search for spectra available in the VO with the 'all VO' button in the server selector window.
• Find spectra available from the Hubble Space Telescope, and view the positions of the spectra (and sometimes thespectral slit aperture) on the image. Make a plane containing all the spectra positions, and cross match these with the positions of the HII regions.
• Start VOSpec ( Web Start: http://esavo.esac.esa.int/webstart/VOSpec.jnlp ) and display some of the spectra, by clicking on the spectra in the server selector window, and 'Load in -> VOSpec'.
• Check VizieR for more detailed catalogues of HII emitting regions in M51. This can be done via Aladinor via the more detailed VizieR interface.
• (Advanced - compile a list of bright HII regions in M51 and query VizieR with this list

-- MarkAllen - 15 Jun 2009