select a result (e.g. POSSII F-DSS2 image at 0.658um with OBS_ID=270) clicking on it, the "Data info frame" window should pop-up with image metadata content
click "Load" to upload the image in Aladin (you can close the "Data info frame")
in the server selector choose the "SkyView" tab to search other M51 images
fields should be already filled up, try to "Submit" for 3 images changing only the "Surveys" field to: VLA First 1.4GHz, H-ALPHA COMP and VLSS
change to "4 panels" view to manage all the downloaded images
menu "View -> 4 panels" or click on the split icons at the bottom of the image display
click one after the other the image planes in the Aladin planes stack to display the images or simply drag and drop the planes on the four panels
try the "match" icon (at image display bottom near split icons) to zoom and/or pan simultaneously the four images (tip: clicking twice will make the icon red and automatically sinchronize also the image orientation)
again in the server selector change tab to "Sloan"
click "Submit" (fields should be already filled correctly)
"mouse over" the results for the five (u,g,r,i,z) filter subsets to show the footprint of the retrieved results over the already loaded images (switch back to 1 panel view if you prefer)
select, by ticking the box on the left of the desired image, the 5 images (1 per filter) that better overlap the galaxy
submit to load them
select the "all VO" tab in the upper "Others" tab list of the server selector
untick "catalogues" and "spectra" server options
check the form fields, submit and wait for answers
"mouse over" the results to see the footprint overlap
click on the image (better in 1 panel view) to see the boxes of the results being selected/unselected if clicked point is contained in them (tip: easier to see in the SDSS results that are the same of the Sloan images already downloaded)
make a colour composite image using the Aladin RGB tool
click the "rgb" icon in the vertical toolbar between image display and planes' stack (or menu "Image -> RGB image builder...")
select from the drop down menus the images for the red, green and blue components and click "Create"
(optionally) use the multi-panel view to display the false color image along with its components or other images and try again the match tool for panning and zooming simultaneously the images
try the transparency tool dragging the slider to see image overlay (at the bottom side of each image plane there's a sliding little rectangular cursor, drag it)
get back to server selector and choose the "Simbad" tab in the "Catalog servers" tab column on the right
given the fields are already filled, select "- no filter -" for "Display filter"
submit to load the catalog in a new Aladin plane
right-click the newly created plane and click "Properties..."
switch through "dedicated filters" to see the various objects superposed to the image
try clicking "This filter on the stack plane for editing" to create a "filter" plane on the stack and see how to handle multiple information on the same image (have a look at the script in the "Advanced Mode" tab)
source filtering can also be done interactively in Topcat (start it), use the SAMP enabled interoperability of the two tools to send the Simbad catalogue to it
right-click the Simbad plane and "Broadcast selected tables to..." topcat (also possible through the "Interop" menu)
in Topcat (should have received the table) click the "Display table cell data" (4th icon from left, or menu "Views -> Table Data") to view table values
plot catalogue positions and try to define a subset to be sent back to Aladin
click "Scatter plot" (or menu "Graphics -> Plot")
use menu "Subsets -> Draw Subsets Region..." (or 9th icon in the icons' bar) and, left mouse button pressed, define a closed region on the plot
use menu "Subsets -> Finish Drawing Region..." (or re-click 9th, 'ticked' icon) to define the subset ("Add" it)
(alternatively use the "column data" display to select rows and define a subset)
in the main Topcat window select the newly created subset using the "Row subset" dropdown menu and send it back to Aladin using "Interop -> Send table to... -> aladin"
get back to Aladin to view the new plane and display its points, if the "table view" in Topcat is open see how SAMP allows row automatic selection and highlighting when clicking on a catalogue point in the Aladin display
(if not the table view keep the Topcat scatter plot opened and look the sinchronization between Aladin and Topcat point selection)
search for more information about HII regions in M51, in the Aladin server selector choose now the "All Vizier" tab
enter "HII" in the "Author, free text..." field and submit
submit one or more catalogues from the results window (e.g. J/ApJ/633/871)
send the table to Topcat to view the full table and/or click the catalog points in Aladin to see full details
(don't discard this Topcat table as we will use it in the last point of this use case)
start VOSpec and display some spectra
in the Aladin server selector choose "all VO" tick only the "spectra" server option and submit
mouse over collapsed server results looking at Aladin image display to see what positions the spectra refer to (one or more "S"s should appear there)
click over a result and, from the "Data info frame" click "Load in..." VOSpec to display the spectrum there
use Topcat to prepare a list of bright HII regions of M51 and query Vizier for more details on them
diplay the table data for the Vizier table (sent before from Aladin)
display the column metadata to identify the luminosity of your choice for the brightness
use a scatter plot to draw a region in a "x" versus luminosity plot to define the wanted "bright" subset
(optionally) send the table to Aladin to see HII regions' positions in M51 (remember to select only the subset in the main Topcat window before broadcasting)
in the column metadata display (pay attention only the "bright" set is displayed) make visible only the RAJ2000 and DEJ2000 columns
from Topcat main window menu use "Save table" to write and ASCII table of the "bright" HII regions' positions defined above
open the saved file to remove the quotes from the positions (unless Vizier will not understand them)
open the Vizier service page: http://vizier.u-strasbg.fr/viz-bin/VizieR
enter "M51" in the "Words matching author's name, word(s) from title, description, etc." field (just under the "light green bar")
check the "Use LISTs of Targets" box on the right and click "Find Catalogues"
select one, some or "All" of the resulting catalogues and click "Query selected catalogues"
at the really bottom of the new page use the file input field to load your saved positions file and click "Submit Query"