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This web site runs actually under twiki and will be saved statically in the comming weeks. If you want to bookmark this web site, please use the following url which will be permanent: http://www.jmmc.fr/VltiSchool2010 One copy of the key informations will also be saved under the European Interferometry web site.

Two lines as a very short Introduction of the Virtual Observatory

The Astronomical Virtual Observatory aims to offer tools to astronomers that breaks down the difficulties of making all work together:

• make data access and discovery easy even if it is too big to fit onto your local machine
• make tools able to make more that the sum of what each of one can do, thanks to the interoperability

This effort is driven by local national and international communities. Please visit the WWW.IVOA.NET web site.

Objective of this tutorial

To give a first overview of VO standards and VO tools, we install onto the local server of the school a copy of one comming catalogue provided by JMMC : Jmmc Stellar Diameter Catalog. This tutorial also uses Topcat and Aladin

Get the catalog content of one particular sky area

1. Launch topcat ( $ topcat-full )
   1. Enter menu: VO -> Cone Search
   2. Copy following ( too long but for demo ) url into field Cone Search URL : http://server.org:8080/jsdc-dsa/SubmitCone?DSACATTAB=jsdc.v1_0b3
   3. Define ( by hand ) RA DEC and search radius

Do some plots

Sky Plot

1. Select your data in the table list of the main topcat window
   1. Enter menu: Graphics -> Sky
   2. Assert that Longitude Axis is ra column and Latitude is dec column
   3. Try the Plot points with radial as well as angular coordinates button and fill the Radial Axis field with 1/plx
   4. Enjoy your cone Search by rotating the plot with the mouse.
   5. Try to add auxiliary axis and some other various features....

You can do bigger or smaller Cone Searches . and use it into the Table Combo box of the plots.

2D Plot

1. Select your data in the table list of the main topcat window and press
   1. Menu: Graphics -> Plot
   2. Fill X Axis with Vmag and Y Axis with Bmag -Vmag

Send data to another VO program

1. Launch Aladin ( $ Aladin ) do not launch the old scisoft aladin version but use Aladin
2. Come back to Topcat
3. Select your data in the table list of the main topcat window
4. Enter menu: Interop -> Send table to... -> aladin
5. Try to select one area into aladin and view the selection into one 2D plot of topcat : this is the simplest interoperability level.

Execute your own script on each star selected into Topcat

1. Select your data in the table list of the main topcat window
2. Define one new Activation Action from the Current Table Properties panel
3. Choose Execute Custum Code and fill with exec("computeVisibility.py",toString(LDD),toString(e_LDD))
4. Click into one row of the table or onto one graphic and read the konsole output

Exercises

Multi Conesearch

How many stars of the JSDC JMMC catalog are located to a maximum distance of 1 degrees of the list of sources already seen in one previous tutorial .

• sources.vot: List of sources into votable format

Note: It is easy to add new coordinates columns in many coord systems :

1. Select your table in the main topcat window
2. Enter Menu Views -> Column info
3. Just add new sky coordinates.

-- Proposed by the JMMC technical team