3. A First Query

To follow the examples, start TOPCAT and select TAP in the VO menu.

In TAP URL: at the bottom of the window, enter http://gaia.ari.uni-heidelberg.de/tap and click ”Use Service”.

At the bottom of the form, at Mode: check “Synchronous” and enter

SELECT TOP 1 1+1 AS result FROM gaiadr1.tgas_source

in the text box, then click “Ok”. This should give you a table with a single 2 in it. If that hasn’t worked complain.Copying and Pasting from http://docs.g-vo.org/adql-gaia is legal.

Note that in the top part of the dialog there’s metadata on the tables exposed by the service (in particular, the names of the tables and the descriptions, units, etc., of the columns). Use that when you construct queries later.

Markus Demleitner

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